Complete Reference · IQ Correlations Atlas · Compiled 2024–2025 · v4 · 57 sections + references

Everything That Correlates
With Intelligence

A comprehensive reference document covering all empirical findings, causal relationships, lifestyle patterns, physical correlates, environmental factors, behavioral tendencies, qualitative observations, and anecdotal clusters associated with IQ — synthesized from primary literature. Effect sizes are approximate. Correlation is not causation except where noted. r-values rounded.

+ correlation with IQ
− correlation with IQ
mixed / nonlinear
causal evidence
qualitative / anecdotal

How to read the colors

Green (+) means higher IQ is associated with more of that trait. Red (−) means higher IQ is associated with less of that trait. Neither color is a value judgment — red does not mean "bad" and green does not mean "good." For example, myopia is a negative health outcome but correlates positively with IQ, so its bar is green. Conversely, binge drinking is harmful but correlates negatively with IQ, so its bar is red. Bar length = approximate effect size. Blue bars = causal evidence regardless of direction.

⚠ Disclaimer

This atlas was compiled with significant AI assistance (Claude, Anthropic). While real studies are cited throughout, some entries may contain hallucinated citations, misattributed findings, or imprecise effect sizes. This is a reference tool and conversation starter, not a peer-reviewed document. Verify any finding against the original source before citing it. Correlation ≠ causation unless explicitly noted. See the GitHub README for full methodology and limitations.

01

Cognitive & Thinking Style

These are the most mechanistically direct correlates — they overlap heavily with what IQ tests actually measure, making some of these partly tautological.
Processing & Speed
Working memory capacity
+
r≈.50-.60
Processing speed
+
r≈.40-.50
Reaction time (faster = higher IQ)
+
r≈.30-.50
Inspection time
+
r≈.30-.45
Finger tapping speed
+
r≈.20-.30
Cognitive flexibility / shifting
+
r≈.30
Reasoning Style
Abstract thinking preference
+
Systems-level thinking
+
Need for cognition (enjoying thinking)
+
Deliberate System 2 engagement
+
Pattern recognition speed
+
Belief updating from evidence
+
Failure Modes
Overcomplicated reasoning errors
+
"Clever sillies" effect (Charlton)
+
Analysis paralysis
+
Overconfidence in own reasoning
+
Common sense deficits (social domain)
~
Resistance to social pressure updating
02

Personality & Traits

Big Five Correlates
Openness to Experience
+
r≈.30-.40strong
Conscientiousness
+
r≈.10-.20
Introversion
+
r≈.15-.20
Agreeableness
r≈−.10
Neuroticism
~
mixed
Extraversion
~
negligible
Other Traits
Intellectual curiosity
+
Cognitive engagement / need for challenge
+
Tolerance for ambiguity
+
Non-conformism
+
Perfectionism (adaptive)
~
Temporal discounting (delayed gratification)
+
Social Personality
Social conformity
Cognitive empathy
+
Affective empathy
~
Psychological neoteny (staying adolescent)
+
Novelty-seeking / boredom proneness
+
Rule-following / authority respect
03

Physical Body Correlates

r≈.25
Brain volume ↔ IQ
16 pts
IQ gap fastest vs slowest walkers
12 pts
IQ gap attractive vs unattractive (UK sample)
r≈.20
Myopia ↔ IQ
Brain & Neurology
Brain volume (MRI measured)
+
r≈.25
White matter myelination quality
+
Cortical thickness trajectory (rate of change)
+
Cortical glucose efficiency (less = smarter)
neural efficiency
Head circumference
+
r≈.19
Nerve conduction velocity
+
Physical Function
Walking speed (gait velocity)
+
r≈.38striking
Grip strength (predicts old-age IQ)
+
Lung capacity (peak expiratory flow)
+
Height
+
r≈.15-.25
Facial attractiveness (contested)
~
contested
Symmetry / developmental stability
+
Eyes & Senses
Myopia (nearsightedness)
+
r≈.20-.25
Myopia (not hyperopia) direction matters
+
pleiotropic
Top IQ quartile: myopia risk 2.4× higher
+
Visual inspection time
+
Handedness
Right-handers vs left-handers (mean IQ)
~
d=−0.07negligible
Left-handers: wider IQ variance (overrep at both tails)
~
Ambidextrous: slightly lower mean IQ
Ambidextrous: higher magical ideation (less lateralized brain)
+
Left-handers: higher verbal IQ vs performance IQ
~
Left-handed college men: ~15% higher earnings
+
one study
04

Lifestyle Patterns

Key Section
Most lifestyle correlates run both directions: high IQ → healthier choices, AND healthier environments → higher IQ. Causality is typically bidirectional. The Mendelian randomization evidence (using genetic variants as instruments) gives the cleanest causal read.
Alcohol — The Paradox
Total alcohol consumption (any drinking)
+
paradox
Likelihood of drinking at all (vs abstaining)
+
OR=1.58
Binge drinking / heavy drinking
Alcohol-related morbidity/mortality
Trying alcohol at all (novelty exploration)
+

The paradox in plain language: Higher-IQ individuals are more likely to drink alcohol at all, but when they drink, they drink less problematically. Lower-IQ individuals who drink are more likely to binge. The U-shaped relationship means very high and very low IQ groups drink the most total alcohol — for opposite reasons (exploration vs. coping).

Smoking
Current smoking status
MR evidence
Smoking initiation
Smoking cessation (quitting)
+
Number of cigarettes per day
Childhood smoke exposure lowers IQ
causal

Mendelian randomization studies support genuine causality here: genetically proxied intelligence reduces smoking likelihood and increases cessation. Brothers who smoke score lower IQ than their non-smoking brothers — controlling for family environment.

Exercise & Physical Activity
Cardiovascular fitness (general)
+
Moderate / less vigorous exercise
+
r≈.17
Vigorous exercise at work/home
~
curvilinear
Exercise during adolescence predicts adult IQ
+
Swedish conscripts: fitness predicts higher IQ
+
Neurogenesis via aerobic exercise
+
mechanism
Diet & Food Habits
Dietary quality score (children)
+
r≈.24
Fish consumption (omega-3 rich)
+
Vegetarianism
+
OR=1.38
Meal skipping (higher IQ, counterintuitively)
+
unexpected
Snacking between meals
+
mixed
Breakfast eating (children)
+
Drugs & Substances
Cannabis lifetime experimentation (not heavy use)
+
novelty
Heavy/chronic cannabis use
~
Stimulant prescription (ADHD medication)
+
2e profile
Drug experimentation in adolescence (UK Biobank)
+
Drug addiction / chronic abuse
Reading & Media
Books read per year
+
Non-fiction reading preference
+
Books in home (children's IQ)
+
Book reading (readers have 20% lower mortality)
+
Television watching (childhood)
Heavy social media use (children)
05

Sleep & Chronotype

Night Owl Correlates
Eveningness (night owl preference)
+
r≈.08
Night owls score 7–13% higher on cognitive tests
+
26,000 UK Biobank
Night owls: higher GMAT scores (MBA students)
+
Night owls: better working memory
+
Morningness: lower cognitive ability
r≈−.04
Academic achievement (morning types outperform despite lower raw IQ)
reversal
Sleep Duration & Quality
Optimal sleep (7–9 hrs) → best cognition
+
causal
Short sleep (<7 hrs) → cognitive impairment
Long sleep (>9 hrs) → lower cognitive scores
High-IQ individuals: later work start times (not biology)
~
MENSA study
Savanna Theory: nocturnal = evolutionarily novel
~
Kanazawa
06

Health, Longevity & Mental Health

Physical Health
All-cause mortality (lower risk)
Longevity / lifespan
+
Cardiovascular disease risk
Obesity / BMI
Stroke / dementia risk
Lower inflammation markers in midlife
Immune & Allergy (Hyper-Brain/Body)
Environmental allergies
+
MENSA: 213%↑
Asthma
+
MENSA: 108%↑
Autoimmune disease
+
MENSA: 84%↑
High IQ (>160): 44% have allergies vs 20% norm
+
UK Biobank: effect weaker in non-MENSA sample
~
sampling bias
Mental Health
Anxiety disorders
+
MENSA: 2×
Depression
~
ADHD (2e profile)
+
Autism spectrum (overlap at high-IQ tail)
+
Bipolar disorder (creative/artistic overlap)
~
Existential depression / meaning crisis
+
qualitative
07

Social Behavior & Sexuality

Social Patterns
Preferring alone time (satisfaction)
+
Social network size (fewer friends)
Friendship depth (deeper, fewer)
+
Loneliness (very high IQ)
+
Social time satisfaction
Gullibility / scam susceptibility
Investment fraud vulnerability (paradox)
+
anecdotal
Sex & Reproduction
Age at first sexual intercourse (later)
+
Number of sexual partners (fewer)
Frequency of sex (less)
Teen virginity rate (higher at top of IQ)
+
Slow life history strategy overall
+
Same-sex behavior experimentation (UK Biobank)
+
exploration
Bisexuality: slightly higher IQ vs straight
+
small
08

Environmental & Causal Factors

Causal Evidence
These are among the most important findings in the entire IQ literature — not correlations but genuine causes, many of them modifiable. Effect sizes are large and implications for public policy are profound.

Lead Exposure — Most Preventable IQ Suppressor

Effect size: Blood lead from 2.4→10 μg/dL: −3.9 IQ points. From 10→20: −1.9 pts. The dose-response curve is steepest at low doses — there is no safe threshold.

Mechanism: Lead crosses the blood-brain barrier, damages hippocampal neurons, disrupts synaptic function. Children absorb 4–5× more lead than adults from the same source.

Policy relevance: Removal of leaded gasoline correlated with measurable IQ gains and crime rate reductions in subsequent generations. Lead remains in soil near major roads and in older housing paint. Disproportionately affects low-income and minority neighborhoods.

Blood lead >10 μg/dL → IQ deficit
causal
Low-level exposure (<7.5 μg/dL) — still significant
no safe threshold

Iodine — Largest Single Modifiable IQ Factor Globally

Effect size: Severe deficiency: up to −15 IQ points. Mild maternal deficiency: reduced reading ability and IQ at age 6.

Mechanism: Iodine → thyroid hormones → brain development. First trimester is most critical. The fetal brain is entirely dependent on maternal thyroid hormone supply during early development.

Historical experiment: US iodization of salt in the 1920s caused measurable IQ gains in previously-deficient regions; iodine-sufficient regions showed no change — a clean natural experiment for causality.

Modern risk: Sea salt, artisanal salt, and reduced table salt use have quietly reduced iodine intake in developed countries. ~50% of women of childbearing age may be mildly deficient.

Deficiency in pregnancy causes child IQ loss
causal
Iodization programs raise population IQ
+
causal
Other Environmental Suppressors
Air pollution / particulate matter
evidence
Childhood secondhand smoke exposure
−2–10%
Fluoride (high exposure, contested)
contested
Prenatal alcohol exposure (FASD)
causal
Hospitalization from infection: −1.76 IQ pts
Green space / nature access (children)
+
Poverty & Bandwidth
Poverty cognitive load: ≈−13 IQ points (functional)
Mani et al.
Financial scarcity depletes executive function
IQ heritability rises as SES equalizes
~
Low SES: fewer books, less stimulation
Each additional year of schooling: +0.6–1 IQ pts
+
causal
09

Nutrition & Micronutrients

Deficiency Effects on IQ
Iodine deficiency
−15 pts
Iron deficiency (early childhood)
Zinc deficiency
Omega-3 / DHA deficiency (maternal)
Vitamin B12 deficiency
Folate / folic acid deficiency
General malnutrition / stunting
causal
Positive Nutritional Factors
DHA supplementation (maternal, FADS2 C-carriers)
+
gene-gated
Fish consumption in childhood
+
Breastfeeding (FADS2 C-allele carriers)
+
+6.8 pts
Breastfeeding (GG homozygotes)
~
≈0 pts
Breastfeeding confounded by maternal IQ
~
confounded
Iodized salt (population-level gain)
+
historic
Developmental Factors
Birth order (first-born advantage)
+
+1 IQ pttrivial
Low birth weight / preterm birth
Mother's age at birth (younger = slight risk)
Mother's IQ (strongest predictor of child IQ)
+
Music lessons at age 6 (piano/voice): +3 IQ pts
+
Twin study: music → no IQ effect (genetic confounder)
~
10,500 twins
10

Hobbies & Interests

Intellectual Hobbies
Reading (non-fiction)
+
Language learning
+
Coding / programming as hobby
+
Collecting & Systems
Taxonomy-based collecting hobbies
+
Musical instrument playing
+
Cat preference over dog ownership
+
proxy
Eclectic, hard-to-categorize hobby mix
+
Social & Cultural
Attending museums, galleries
+
Travel frequency / curiosity about other cultures
+
Dark humor appreciation
+
Philosophy / ethics interest
+
Volunteering / civic engagement
+
Workaholic tendencies
+
11

Music Preferences

The key variable is vocal vs. instrumental, not genre complexity. Preference for instrumental music (classical, jazz, ambient, film scores, smooth jazz) predicts higher IQ. Liking vocal music has no IQ association — many high-IQ people enjoy vocal music too. The signal is in the preference for purely instrumental pieces.

The Kanazawa/Savanna Theory explanation: instrumental music is evolutionarily novel — all ancestral music was vocal. Preferring a non-vocal form requires overriding evolved defaults, which high-IQ individuals do more readily across many domains.

Higher-IQ individuals also use music differently — as cognitive background rather than emotional regulation. Neurotic and non-conscientious individuals use music primarily for emotional self-regulation regardless of IQ.

Positive Correlates
Instrumental music preference
+
key signal
Classical music
+
Jazz
+
Film soundtracks / ambient
+
Big band
+
Minor mode preference
+
Negative / Mixed
Gospel music preference
Rap / hip-hop preference
Rebellious / conventional pop
Complex cognitive use of music
+
Emotional use of music (regulation)
~
Note

Opera (cognitively complex, vocal) shows no IQ correlation — undermining the "complexity" theory. This confirms the vocal/instrumental split, not complexity, is the operative variable. Progressive metal, jazz-fusion, math-rock show positive associations in anecdotal data. Individual variation is massive — IQ is a poor predictor of any specific person's music taste.

12

Politics, Beliefs & Values

Political Knowledge & Style
Political knowledge / factual accuracy
+
Having a political opinion at all
+
Center-right / centrist positions (Brazil sample)
+
Extremism (left or right)
U-shaped
Dogmatic thinking
Nuanced, non-binary political views
+
Social Values
Social liberalism
+
r≈.20-.30
Economic liberalism / free market
~
≈flat
Libertarianism
+
Acceptance of homosexuality
+
r≈−.58 (non-acceptance)
Racial tolerance / prejudice reduction
+
Trust in institutions
~
Religion & Metaphysics
Religiosity (frequency, belief intensity)
r≈−.20-.24
Atheism / agnosticism
+
Analytic thinking overrides intuitive belief
+
Conspiracy belief susceptibility
Superstition / magical thinking
Vegetarianism as ethical choice
+
13

Qualitative Observations & Anecdotal Clusters

Anecdotal
These are drawn from clinicians, teachers, longitudinal observers, and consistent first-person accounts. Not peer-reviewed RCTs — but patterns that appear repeatedly across independent observers. Treat as strong hypotheses, not established facts.
Analysis Paralysis

High-IQ individuals consistently report that simple decisions — what to eat, whether to reply to a message — become cognitively expensive. The more options you can model, the harder it is to commit. This is option paralysis applied to everyday life. The cost-benefit analysis never terminates cleanly.

Reading the Room at the Wrong Speed

Teachers, therapists, and managers consistently observe that high-IQ individuals process content faster than emotional tempo. They resolve the intellectual puzzle before the person has finished wanting to be heard. The effect looks like coldness or dismissiveness but is actually processing speed mismatch.

The Intensity of Boredom

Very high-IQ individuals describe boredom not as mild irritation but as physically aversive — almost painful. A nervous system tuned for high cognitive throughput experiences low-stimulus environments as genuine deprivation. Consistent with the Dabrowskian overexcitability framework.

Memory Paradox

High-IQ individuals often have excellent semantic memory (facts, patterns, arguments) but weaker autobiographical memory (when things happened, what people said). Processing at high abstraction extracts principles rather than encoding episodes. They remember the insight but not the conversation that produced it.

Children's Questions That Skip Steps

Teachers of gifted children consistently report questions that seem random or off-topic — but are actually 3–5 logical steps ahead of where the lesson is. The child has processed the intermediate steps internally and is asking from a different position. Often misread as inattention.

The "I Know I'm Right" Trap

High-IQ individuals update well from evidence but poorly from social pressure. This is sometimes adaptive (intellectual independence) and sometimes catastrophic (being correct while making collaboration impossible). The failure mode is holding a correct position in a way that destroys the relationship.

Psychological Neoteny

Charlton (2009) documented the tendency of highly intelligent people to remain in a state of perpetual novelty-seeking adolescence — declining to settle into conventional adult roles, conventional values, or conventional thinking. A form of sustained openness that can look like arrested development.

The Gifted Child → Disappointed Adult Arc

Longitudinal observers note that children identified as gifted often feel their adult lives don't match the implicit promise. The gifted label creates an expectation of exceptional contribution that most lives — even successful ones — don't fulfill. This specific dissatisfaction has been called "bright line depression."

Asynchronous Development

Gifted children commonly show advanced reasoning in one moment and emotional responses appropriate to their calendar age (not mental age) in the next. Parents and teachers who expect cognitive age to predict emotional age consistently misread these children. The two tracks develop at different rates.

Smart People Are Easier to Con

Financial fraud investigators and con artists consistently note that high-IQ, high-income individuals are disproportionately targeted — and caught. They engage with complex pitches that low-IQ individuals simply ignore, and their confidence in their own analytical ability creates a blind spot for emotional manipulation.

The Longing for Cognitive Peers

One of the most consistent self-reports among very high-IQ adults: the specific loneliness of rarely meeting people who can match their processing pace. It's not that they dislike ordinary people — it's that conversation at a different cognitive register is chronically unsatisfying in the way that running at half speed is physically unsatisfying.

Workaholism Pattern

High-IQ individuals often bury themselves in work — not because of external pressure but because work is one of the few socially acceptable venues for sustained cognitive engagement. Japan (high average IQ) has among the highest annual work hours globally. The work fills the bandwidth that other environments can't.

14

Taboo, Contested & Fringe Findings

Sensitive
These findings are real data points that get suppressed for political reasons — but suppression doesn't make them false. Handle with calibrated skepticism, not blanket rejection. Effect sizes and data quality vary enormously.
Physical Attractiveness (Contested)
UK NCDS: attractive vs unattractive, IQ gap
+
r=.38 (12 pts)
US Add Health sample
+
r=.13
Large twin study: no phenotypic correlation
~
null result
Men: can gauge male IQ from face photos
+
Czech study
Women: cannot gauge IQ from face
~
Mechanism: cross-trait assortative mating or f-factor
~
theoretical
Sexual Orientation & Gender
Gay men: higher IQ than straight men (some studies)
+
small, inconsistent
Bisexuality: higher IQ vs straight (one large sample)
+
Rare sexual orientations: substantially higher IQ
+
β=0.93
Boyhood femininity in straight men → higher IQ
+
Girlhood femininity in straight women → lower IQ
Savanna-IQ: non-heterosexuality as "evolutionarily novel"
~
Kanazawa
Height & Body (Genetic Quality)
Height ↔ IQ correlation
+
r≈.15-.25
Shared genes (pleiotropy) explain most
~
twin modeling
Assortative mating amplifies both traits together
~
Facial symmetry ↔ IQ
+
weak
f-factor hypothesis (general genetic quality)
~
Miller
Flynn Effect & Reversal
IQ rising ~3 pts/decade (20th century)
+
Flynn effect
Flynn effect reversed in Scandinavia (~1990s)
Lead removal contributed to Flynn gains
+
partial
Iodization contributed to Flynn gains
+
partial
Screen time era correlates with reversal
temporal
Verbal / abstract reasoning most affected
15

Giftedness — The Label Problem

What is real: The upper tail of cognitive ability exists, is measurable, and produces genuine developmental consequences. Children at the extreme upper end process information faster, form more complex abstractions, and experience conventional educational environments as genuinely under-stimulating — not as a preference but as a functional mismatch.

What is constructed: The category boundary (IQ 130, top 2%) is entirely arbitrary. There is no discontinuity in the distribution at that point. A child at 128 and one at 132 are cognitively nearly identical. The cut-off is a policy decision masquerading as a biological fact.

The inflation problem: Giftedness definitions have expanded to include creativity, leadership, emotional sensitivity, and artistic talent — creating a category so broad it no longer carves nature at its joints. In practice, gifted programs systematically over-identify white, affluent children and under-identify poor and minority children with identical ability profiles.

Dabrowski's Overexcitabilities — real but misused: The five OEs (psychomotor, sensual, intellectual, imaginational, emotional) describe real phenomenological patterns but are probably better explained by existing personality dimensions (Openness + neuroticism) than by a separate gifted construct. They're useful descriptively; they're abused as identity markers.

Terman's Lesson: His 1,528 high-IQ children became above-average adults — healthier, wealthier, better-adjusted than average. But they did not produce genius. Two children he rejected as "not gifted enough" won Nobel Prizes. High IQ in childhood predicts a better-than-average life trajectory, not exceptional contribution.

The adult gifted identity: For many adults, "gifted" functions as an explanatory framework for alienation, underachievement, and social failure. This is sometimes accurate and sometimes a sophisticated avoidance of more actionable self-examination. The framework can close off: every difficulty becomes evidence of the burden of giftedness.

16

Meta-Findings & Structural Notes

Effect Size Context
IQ → educational attainment
+
r≈.55
GMA → job performance (Schmidt & Hunter 1998)
+
r≈.51 (old)
GMA → job performance (Steel & Fariborzi 2025)
+
r≈.16
IQ → income
+
r≈.30-.40
IQ → longevity
+
r≈.25-.30
IQ heritability (adults)
+
h²≈.70-.80
IQ heritability (children)
+
h²≈.20-.40
Identical twins reared apart IQ correlation
+
r≈.86
Key Structural Facts

IQ explains 20–30% of variance in most life outcomes — the other 70–80% is personality, circumstances, relationships, timing, and luck. It's consequential but not determinative.

System Integrity Hypothesis (Deary): IQ is a proxy for whole-organism biological quality. The correlates with walking speed, grip, lung capacity, longevity, and inflammation all express the same underlying variable: how cleanly the organism's systems operate.

The 2025 job performance bombshell: Steel & Fariborzi showed the classic 0.51–0.65 IQ–job performance correlations were inflated by overcorrection for range restriction. True correlation may be ~0.16. The entire psychometric hiring industry was built on numbers roughly 3× too large.

Gene-environment interplay: IQ is highly heritable AND highly malleable. These are not contradictory. Genes set potentials; environments determine expression. The same child with lead poisoning, iodine deficiency, and poverty versus adequate nutrition and stimulation can differ by 20+ IQ points.

Taleb's critique: In fat-tailed environments (entrepreneurship, creative fields, science), IQ's predictive value collapses. It predicts linear, reliable performance well; it predicts extreme outlier outcomes poorly. The correlation for winning a Nobel Prize is essentially random above ~120 IQ.

17

Vocational Interests & IQ (RIASEC)

Holland's RIASEC framework (Realistic, Investigative, Artistic, Social, Enterprising, Conventional) maps interests onto six types. A meta-analysis of 27 studies (N=55,297) found meaningful but modest relations between interest types and cognitive ability. Ackerman & Heggestad (1997) and Stanek & Ones (2023) supply the primary data here.
RIASEC × g correlations
Investigative interests (science, analysis, research)
+
r≈.20-.30strongest
Artistic interests (writing, music, visual arts)
+
r≈.10-.20
Realistic interests (tools, machines, outdoor)
+
spatial only
Social interests (helping, teaching, caring)
~
≈0
Enterprising interests (leading, persuading)
~
≈0
Conventional interests (data, structure, clerical)
neg w/ Openness
Investigative occupations: highest g requirements
+
O*NET data
Longitudinal & Personality Links
Childhood Openness/Intellect → Investigative career 40 yrs later
+
longitudinal
Childhood Openness/Intellect → Artistic career 40 yrs later
+
longitudinal
Childhood Openness/Intellect → Conventional career
Artistic interests + verbal ability (crystallized)
+
Investigative interests: both fluid AND crystallized g
+
Verbal IQ (not performance IQ) drives most interest–g links
+
2024 finding

What this means in plain language: Higher IQ individuals are drawn to Investigative environments — science, research, philosophy, analysis — and this is the strongest and most replicated interest-intelligence link. Artistic environments (writing, music, visual arts) show a secondary pull. Conventional environments (structured data processing, clerical work) show a mild negative pull. Social and Enterprising show essentially no IQ correlation — interpersonal skill and leadership appetite are orthogonal to g. Crucially, a 40-year longitudinal study showed that childhood Openness/Intellect predicted adult Investigative and Artistic occupations — and negatively predicted Conventional ones — independent of other personality traits.

The verbal asymmetry (2024): Verbal IQ predicts political orientation, civic engagement, and sociopolitical attitudes at twice the rate of performance IQ. This suggests that the social and ideological dimensions of intelligence are more linguistic than spatial — what you do with words shapes your worldview more than what you do with shapes.

18

Personality Facets — Below the Big Five

Stanek & Ones (2023, PNAS) meta-analyzed 60,690 relations between 79 personality and 97 cognitive ability constructs — the largest such analysis ever conducted. Most important finding: the action is at the facet level, not the Big Five domain level. Domain-level correlations conceal and reverse at the facet level. Data from millions of individuals across 3,543 meta-analyses.
Openness facets
Ideas facet — intellectual engagement, love of debate
+
strongest
Fantasy facet — imagination, inner world, vivid daydreaming
+
verbal r
Aesthetics — appreciation of art, music, beauty
+
Feelings — emotional awareness and depth
+
Actions facet — trying new activities, behavioral novelty
~
Values facet — questioning social conventions
+
Agreeableness facets (surprising splits)
Compassion / interpersonal sensitivity (empathy)
+
r=.26moderate
Politeness facet — deference, avoiding confrontation
r=−.22
Cooperation / willingness to collaborate
+
r=.20 (speed)
Modesty — avoiding self-promotion
r=−.17 (fluency)
Aggression / hostility
r≈−.20
Honesty-humility (HEXACO) — overall
~
Extraversion & Neuroticism facets
Activity facet of Extraversion — energy, pace, engagement
+
r=.25 (fluency)
Sociability facet of Extraversion — friendliness, gregariousness
Cheerfulness / positive mood
+
Uneven temper / irritability
notable
Depression facet of Neuroticism
Industriousness (Conscientiousness aspect)
+
r=.32
Cautiousness / routine-seeking
Toughness + provocativeness + leadership (positive!)
+
Kaufman
Orderliness, morality, nurturance, tenderness (negative!)
Kaufman
23 of 45 personality dimensions: zero IQ correlation
~

The key insight from Stanek & Ones (2023): Empathetic, happy, engaged, and compassionate people are more likely to be intelligent than their moody, insensitive counterparts — despite the "tortured genius" stereotype. The moody genius is a narrative artifact; the data points in the opposite direction. Agreeableness overall is weakly or uncorrelated with IQ, but its compassion facet is positively correlated and its politeness facet is negatively correlated — meaning intelligent people tend to care more about others' feelings but less about deferring to hierarchy or avoiding confrontation. This is a subtle but empirically robust split.

On Neuroticism: The overall correlation is weak and contested, but the uneven temper and depression facets specifically predict lower cognitive performance — undermining both the "emotional genius" trope and the idea that neuroticism is systematically intelligence-linked. High general neuroticism appears to interfere with optimal cognitive performance via test anxiety and rumination.

19

Social Impressions — How Others Read Intelligence

These are observations about how high-IQ individuals are perceived by others — the gap between actual intelligence and social impression. Drawn from social psychology, organizational research, and observer studies. Often at odds with internal experience.
The smartest person in the room

High-IQ individuals in group settings are frequently perceived as cold, arrogant, or dismissive — not because they are, but because their faster processing speed creates social asymmetry. They've resolved the problem while others are still framing it. The silence they offer is filled with other people's discomfort. Observers attribute the gap to attitude rather than tempo.

Confident talkers outperform quiet thinkers

Multiple studies find that perceived intelligence — what people in a room think you are — correlates more with confidence and verbal frequency than with actual measured IQ. The person most likely to be seen as intelligent is the one who speaks first and often, not the one who eventually says the most accurate thing. High-IQ individuals who default to listening are consistently underestimated.

The gifted label as social isolation

Research found that students labeled as "gifted" reported that the label made friendships with non-gifted peers harder — not because of ability gaps, but because the label itself created social distance. Being tagged as cognitively different activates in-group/out-group dynamics in children immediately and persistently.

Small talk avoidance misread as antisocial

High-IQ individuals consistently report discomfort with small talk — not from social anxiety but from mismatch in information density. Surface-level exchanges carry very little data, require significant social performance, and offer no learning. Observers read this avoidance as unfriendliness or social deficiency. It is functionally more like selective bandwidth management.

Perceived as socially deficient when statistically isolated

The social perception literature documents that highly intelligent individuals who become lonely — due to small peer networks and cognitive mismatch — are then further perceived as having social deficits that caused the isolation. The causality is inverted in most observers' minds. The isolation usually preceded the perceived deficiency, caused by environment, not vice versa.

Face accuracy — men only

Observers can gauge the real intelligence of men from facial photographs at slightly above-chance accuracy, but this does not replicate for women. The mechanism isn't facial morphology per se — symmetry and averageness correlate with perceived but not actual intelligence — it's something else being read (possibly microexpressions or gaze behavior during photo capture). Entirely absent in women.

First-impression cues (observed correlates)
Speaking rate — faster speech perceived as more intelligent
+
perception only
Vocabulary precision in casual speech
+
Asking sharp follow-up questions (vs. broad questions)
+
Admitting uncertainty openly — underestimated by observers
perception gap
Glasses wearing — perceived intelligence boost
+
perception only
Swearing in speech — perceived as less intelligent by observers
perception ≠ reality
Reality vs. perception gaps
Swearing fluency: positively correlated with verbal IQ
+
Jay & Janschewitz
Swearing frequency: no significant IQ correlation
~
Yale study
Confident speaker perceived as smarter regardless of content
+
social heuristic
Quiet, listening behavior misread as low intelligence
perception error
Self-handicapping language ("I'm not sure, but…") — perceived as dumb
perception error
20

Quirks, Habits & Lifestyle Patterns

This section compiles qualitative observations and smaller empirical studies on specific behavioral habits. Evidence quality varies — some findings are robust (swearing fluency, messy desk creativity), others are single-study or anecdotal. Treat accordingly.
Language & Communication Habits
Taboo/swear word fluency — correlates with overall verbal fluency
+
Jay 2015
Swearing frequency (actual use) — no IQ correlation
~
Yale/Giordano
Vocabulary expansion as active habit — correlated with IQ
+
Talking to self / self-directed speech — aids complex task performance
+
anecdotal
Sarcasm use — higher creativity scores (Harvard/Columbia)
+
single study
Laughing at own jokes alone — "independent thinking" marker
+
observational
Workspace & Focus Habits
Messy desk → more creative, unconventional ideas (judges' rating)
+
Vohs, U.Minnesota
Tidy desk → more conventional, safer ideas
one study
Doodling during listening — 29% better recall than non-doodlers
+
one study, N=40
Fidgeting / physical restlessness — aids focus in high-IQ
+
observational
"Thinkers" more sedentary than non-thinkers (Florida Gulf Coast)
+
small study
Irregular sleep schedules — brain won't stop; erratic but often productive at odd hours
+
observational
Curiosity & Depth Habits
Rabbit hole behavior — obsessive deep-diving into niche topics
+
Accumulating disconnected-looking interests (cross-domain)
+
Asking "why" compulsively — rules must make logical sense
+
Comfort with not knowing — uncertainty as starting point, not threat
+
Revisiting the same problem for weeks/months — patience with ideas
+
Idea generation far exceeding execution capacity
+
observed
Procrastination & Time Patterns
Procrastination — more common in high-IQ ("active procrastination")
+
mixed
Perfectionism as hidden procrastination engine
+
Hyperfocus on chosen problems (hours feel like minutes)
+
Difficulty sustaining attention on unchosen tasks
+
Task priority over comfort — completing at cost of sleep/social
+
Avoiding authority figures who don't justify commands
+
Color discrimination fineness (visual spectrum)
+
Eye movement patterns during problem-solving
+
Contagious yawning susceptibility (perceptual, not empathy)
~
indirect
21

Philosophical Character & Inner Life

These are qualitative descriptions drawn from clinical observations, longitudinal interviews, and consistent self-report patterns across high-IQ populations. Not quantitative correlations — more like the phenomenology of high intelligence. Treat as a coherent portrait, not individual facts.
Beliefs as working hypotheses

One of the most consistent patterns in clinicians who work with high-IQ adults: they hold opinions as provisional, not permanent. When new information arrives, the update is fast and relatively frictionless — not emotionally painful in the way it is for average-IQ individuals. This can look like inconsistency to observers but is actually a form of epistemic hygiene. The flip side: they are sometimes perceived as untrustworthy or "wishy-washy."

Existential depression as cognitive byproduct

Higher intelligence correlates with grappling with questions of meaning, mortality, and cosmic insignificance — not casually, but persistently and sometimes overwhelmingly. The capacity to hold the full frame of one's situation — the randomness of birth, the certainty of death, the scale of the universe relative to an individual life — produces a form of despair that is structurally different from clinical depression. It's described as a tax on awareness.

The "why can't everything be interesting" frustration

A consistent frustration across gifted adults: the gap between the richness of their inner engagement and the flatness of most institutional environments. Jobs, meetings, social gatherings, administrative tasks — designed for median engagement — feel not just boring but slightly insulting. The boredom is experienced as wasted capacity, which produces a specific kind of irritability distinct from simple displeasure.

Self-correction as internal compulsion

High-IQ individuals often report a compulsion to qualify their own statements mid-sentence — to insert caveats, acknowledge exceptions, and undermine their own confident delivery before the listener even has a chance to challenge it. This is related to the "ideas facet" correlation with verbal intelligence: they see the flaws in their own reasoning faster than others do. Socially, this can come across as wishy-washy or neurotic. Epistemically, it's accurate modeling.

Multi-domain curiosity as identity

Many high-IQ adults describe their intellectual curiosity as the stable core of their identity — more fundamental than their career, their relationships, or their opinions. The drive to understand something new is experienced as intrinsically rewarding rather than instrumentally useful. This produces the "rabbit hole" pattern of deep, often economically irrelevant investigation. The value is the understanding, not the application.

Asynchronous development: smart brain, average life

One of the most widely reported subjective experiences of gifted adults: the gap between cognitive age and emotional/social age. They understood Kant at 14 but couldn't manage a rejection without catastrophizing until 30. The intelligence is precocious; the emotional equipment is not. This creates specific forms of suffering that don't fit neatly into either the "successful person" or "struggling person" categories — and that therapists and coaches who don't specialize in high-IQ profiles often completely misread.

Pattern detection as both gift and curse

The same cognitive machinery that allows high-IQ individuals to see connections across disparate domains also produces false positives — perceived patterns in noise, causal stories from correlations, narrative coherence imposed on random events. The very feature that makes them effective at finding real structure also makes them prone to finding structure where none exists. This is the mechanism behind the "intelligent conspiracy theorist" and the high-IQ investor who sees market patterns that don't exist.

Selective intensity over broad engagement

Rather than spreading attention evenly across many interests, high-IQ individuals tend toward deep, sequential obsessions — intensely engaged in one domain for months or years, then switching. The switches can look inexplicable from outside. Inside, they're driven by the feeling that a problem has been "solved enough" — that the most interesting layer has been accessed and the remaining depth doesn't justify continued investment. The characteristic left in the wake is a library of half-explored domains, each of which most people would consider a lifetime's specialization.

The imposter-genius oscillation

Clinicians consistently describe high-IQ adults oscillating between two poles: the private certainty that their perspective is correct (even when they won't say so), and a crippling sense that they are frauds who have fooled everyone into thinking they're competent. The Dunning-Kruger effect partially explains this — the more you know, the more clearly you see the enormous territory you don't know. But it also reflects the mismatch between internal experience (constant doubt, processing cost) and external perception (effortless competence).

Aversion to performing intelligence

A recurring observation: very high-IQ individuals often resist demonstrating intelligence socially, not from modesty but from finding the performance exhausting and the social dynamics it creates unpleasant. Being the "smart one" creates social distance, invites testing behaviors, and attracts the wrong kind of attention. The performance of intelligence is not the same as the exercise of it, and many prefer the latter privately to the former publicly.

Justice sensitivity and moral intensity

Higher IQ correlates with stronger justice sensitivity — a heightened emotional response to unfairness, not just to rules violations but to principle violations. This drives the activism, the moral argumentation, the inability to let injustice go unaddressed in a group setting. It also produces significant interpersonal friction, since the intensity of the moral response is calibrated to the principle, not to the social cost of expressing it.

The "2AM problem" — intrusive thinking that won't stop

Perhaps the most consistent phenomenological report from high-IQ adults across cultures: the inability to turn off the processing when they want to. Problems continue running in background. Solutions arrive mid-shower, mid-conversation, 2 AM while trying to sleep. This is not celebrated as genius — it's experienced as an intrusion. The brain's capacity to continue processing without permission is described as both their greatest asset and their most reliable source of suffering.

22

Rationality & Cognitive Biases

Stanovich
This is arguably the most important corrective in the entire atlas. Keith Stanovich's decades of work show that IQ and rationality are partially dissociable — "dysrationalia" (irrational behavior despite adequate intelligence) is real, measurable, and common. Some biases are reduced by IQ; others are completely independent of it; and a few are actually amplified by higher intelligence.
IQ-Independent Biases
Myside bias (arguing for own position)
~
r≈.00key finding
Bias blind spot (seeing others' biases, not own)
+
amplified
Noncausal base-rate neglect
~
r≈.00
Framing effects (wording changes choices)
weak
Anchoring effects
r≈−.10
IQ-Reduced Biases
Cognitive Reflection Test (overriding intuition)
+
r≈.40-.50
Belief bias in syllogistic reasoning
Conjunction fallacy resistance
+
Sunk cost resistance
+
weak
Scope sensitivity (proportional response)
+
The Dysrationalia Gap
Rationality correlates with IQ overall
+
r≈.40-.60
But gap is large enough for frequent dissociation
~
Metacognitive calibration (knowing what you know)
+
Intellectual humility
~
mixed
"Sophisticated arguer" effect (IQ weaponizes existing beliefs)
+
Stanovich

The Core Paradox

High-IQ individuals are better at most reasoning tasks — they commit fewer logical errors, update more readily from evidence, and detect others' biases more accurately. But on myside bias specifically — the tendency to evaluate evidence in favor of your existing position — intelligence provides essentially zero protection. The correlation is near zero across multiple paradigms.

Worse: because high-IQ people are better arguers, they are better at constructing sophisticated justifications for positions they already hold. Intelligence becomes a tool for defending priors rather than correcting them. Stanovich calls this the "sophisticated arguer" effect. The practical implication: being smart does not make you fair-minded. It makes you a more effective advocate for whatever you already believe.

23

Financial & Economic Behavior

Investment Behavior
Stock market participation (any investing)
+
20% gapFinnish data
Portfolio diversification (more stocks, mutual funds)
+
Sharpe ratio (risk-adjusted returns)
+
Disposition effect resistance (not holding losers)
+
Investment fees paid (lower)
Tech bubble avoidance (sold before crash)
+
Financial Outcomes
Savings rate (after controlling for income)
+
Credit score
+
r≈.30-.40
Bankruptcy rate
Financial literacy score
+
Payday loan / high-interest debt usage
Entrepreneurship (Nonlinear)
Entrepreneurial entry (starting a business)
+
inverted U
Optimal entrepreneurial IQ range
~
~115-130
Very high IQ (140+) → overrepresented in academia, not startups
Tax avoidance sophistication
+

The Finnish military dataset (Grinblatt, Keloharju & Linnainmaa, 2011) is the gold standard here: ~160,000 males with IQ tested at military induction, matched to complete tax and investment records. Stock market participation increases monotonically with IQ — a 20+ percentage point gap between highest and lowest IQ stanines, persisting even among the top 10% wealthiest. High-IQ investors hold more diversified portfolios, pay lower fees, earn higher risk-adjusted returns, and showed better market timing around the dot-com bubble. The effect is not driven by income or wealth — IQ independently predicts financial behavior even among the affluent.

24

Cooperation & Strategic Interaction

Repeated Games
Cooperation in repeated prisoner's dilemma
+
replicated
Convergence to full cooperation (high-IQ groups)
+
Conditional cooperation (cooperate if partner cooperates)
+
Strategic leniency adjustment (less forgiving of low-IQ errors)
+
Strategy implementation errors (fewer trembling-hand mistakes)
Payoff-sensitivity (cooperation is strategic, not automatic)
+
Social Trust & Interaction
Generalized social trust
+
Lie detection accuracy
~
≈nullnull finding
Leadership emergence (perceived as leader)
+
r≈.25-.30
Leadership effectiveness (curvilinear)
~
1.2 SD optimum
Divorce rates
Authoritative parenting style
+

Proto, Rustichini & Sofianos (2019, 2022) — Intelligence and Cooperation

In one of the cleanest experimental demonstrations in behavioral economics, Proto et al. separated participants into IQ-based groups and had them play repeated prisoner's dilemma games. Initial cooperation rates were similar across groups. But over time, high-IQ groups converged toward near-total cooperation, while low-IQ groups declined toward mutual defection.

The mechanism: higher-IQ players made fewer "trembling hand" implementation errors and had better working memory for tracking partner behavior. They adopted conditionally cooperative strategies (cooperate if partner cooperated last round) and stuck to them. Low-IQ players made more execution errors, causing reciprocal punishment spirals. When mixed together, high-IQ players became less lenient — correctly adjusting for the higher error rate of their partners. This has been replicated (2025 replication at 99% power confirmed all findings).

25

Biomarkers & Physiology

Autonomic & Endocrine
Baseline pupil size (larger = higher Gf)
+
r≈.30contested
Cortisol reactivity (inverted U with cognition)
~
curvilinear
Resting heart rate variability (HRV)
+
Blood glucose regulation / HbA1c
+
Insulin sensitivity
+
Neural Signatures
EEG resting alpha frequency (higher)
+
Default mode ↔ frontoparietal network connectivity
+
Global brain connectivity (network flexibility)
+
P300 ERP amplitude (attention allocation)
+
Cellular & Systemic
Telomere length (slower shortening)
+
mediated
Gut microbiome diversity (elderly samples)
+
emerging
Dental health / teeth remaining (old age)
+
Pain sensitivity (lower threshold — more sensitive)
+
preliminary
CRP / inflammatory markers (lower in midlife)

The pupil size controversy: Tsukahara, Harrison & Engle (2016) found that larger baseline pupil size correlates with higher fluid intelligence (r≈.30–.39 in extreme groups), proposed to reflect locus coeruleus-norepinephrine system regulation. However, multiple independent replication attempts have failed (Robison & Brewer, 2022; Unsworth et al., 2019). The original authors argue failures stem from methodological issues (lighting conditions compressing pupil variability). Status: genuinely contested, with the original team and critics both publishing spirited responses. Tag accordingly.

26

Language & Communication

Verbal Production
Vocabulary size
+
r≈.70-.80strongest proxy
Sentence complexity (subordinate clauses)
+
Reading speed (at equivalent comprehension)
+
r≈.30-.40
Spelling ability
+
r≈.30-.40
Humor production (generating original funny responses)
+
Novel metaphor comprehension
+
Written & Digital
Handwriting legibility
teacher reports
Code-switching fluency (bilinguals)
+
Search query specificity (internet)
+
Source credibility evaluation
+
Typing speed
+
r≈.15-.20
27

Crime, Legal & Risk

Criminal Behavior
Criminal conviction rate
r≈−.20
Recidivism rate (re-offending after release)
Juvenile delinquency
White-collar crime sophistication
+
detection bias
Detection avoidance (smarter criminals harder to catch)
+
Safety & Risk
Traffic accident rate
Hazard perception speed
+
Workplace accident rate
Seatbelt use / safety compliance
+
Jury instruction comprehension
+
28

Aging & Cognitive Reserve

Cognitive Reserve
Rate of cognitive decline (slower)
+
Years of functional independence before dementia
+
Alzheimer's pathology protection (none — same plaques)
~
important null
Steepness of cliff once decline begins
+
paradox
"Use it or lose it" responsiveness (Matthew Effect)
+
Developmental Trajectories
Wilson Effect (heritability rises with age → ~.80)
+
Advanced paternal age (>40) → slightly lower offspring IQ
de novo mutations
Birth season (late winter/spring → slightly higher)
+
small
Sibling count (fewer siblings → slightly higher IQ)
resource dilution
Wisdom (Berlin Paradigm) — necessary but not sufficient
+
r≈.30

The cognitive reserve paradox: Higher childhood IQ delays the visible onset of dementia by years — the brain has more functional capacity to lose before impairment becomes noticeable. But it does not protect against the underlying Alzheimer's pathology (same amyloid plaques, same tau tangles). The result: high-IQ individuals appear fine for longer, then sometimes decline more steeply once the reserve is exhausted. The clinical implication is that by the time a high-IQ person fails a cognitive screening test, their brain pathology may be more advanced than in a lower-IQ person who failed the same test earlier.

29

Technology & Digital Behavior

Adoption & Use
Early technology adoption
+
Social media posting frequency
Content consumption (lurking / reading)
+
Information literacy / source evaluation
+
Gaming
Total gaming hours
~
≈flat
Spatial & Navigation
Spatial navigation ability
+
Mental rotation skill
+
Sense of direction (performance IQ, not verbal)
+
30

Environmental Miscellany & Wild Cards

Environmental Suppressors (Additional)
Chronic noise exposure (childhood, near airports)
High altitude chronic hypoxia (>3,500m)
Fluoride (high exposure — far above Western levels)
Choi et al.
Anesthesia exposure in childhood (>3 hrs cumulative)
FDA warning
Phthalate / BPA exposure (prenatal)
emerging
Positive Environmental
Bilingual environment (executive function boost)
+
debated
Adoption into higher-SES family
+
+4-7 ptscausal
Childhood pet ownership (responsibility/stimulation)
~
confounded
Wild Cards
Voice pitch (lower in men → slightly higher IQ)
+
prenatal T
Exotic/unusual pet choices (reptiles, aquaria)
+
novelty proxy
Death anxiety (lower despite lower religiosity)
Aesthetic sensitivity (visual art, nature, design)
+
Motion sickness / vestibular sensitivity
+
anecdotal

31

Childhood & Developmental Milestones

Early Language & Cognition
Earlier first words (profoundly gifted avg: 9 months)
+
Earlier sentence formation (< 24 months → IQ 107 avg at 30)
+
β=−.17
Sight-reading before age 4 (vs 6–7 typical)
+
Early vocabulary explosion
+
Questioning Santa / Tooth Fairy by age 2-3 (IQ >145)
+
Ruf
Motor & Social Milestones
Earlier walking (standing unaided)
+
weaker than language
Earlier social interaction milestones
+
Preference for talking to adults over peers
+
Organizing/sorting objects by category (as toddler)
+
Milestones at 24 months predict ~20% of IQ variance at age 5–6
+
R²≈.20
Childhood Behavioral Patterns
Asynchronous development (adult reasoning, child emotions)
+
Intense curiosity / relentless questioning
+
Existential concerns before age 5 (IQ>145)
+
Teacher misidentification (inattention mistaken for ADHD)
+
Profoundly gifted: 91% talked early (avg first words 9mo)
+
Davidson

Key nuance: Language milestones are the strongest childhood predictor of later IQ — much stronger than motor milestones (Flensborg-Madsen, 2018; N=821, followed to age 20–34). Walking early has a weak association that largely disappears once language and social interaction are controlled for. The strongest childhood signals: early sentence formation, early social interaction, and spontaneous reading. However, some profoundly gifted children are late talkers (Einstein famously didn't speak until age 4). Early milestones at 4–12 months predict almost nothing; milestones at 24 months predict substantially more (~20% of IQ variance at age 5–6).

32

Academic & University Performance

Grades & Achievement
School grades (strongest single predictor)
+
r≈.40-.70
Exam performance at age 16 (UK, Deary et al.)
+
r=.81N=70K
IQ → GPA (university level, range-restricted)
+
r≈.30-.50
IQ × Conscientiousness interaction (C amplifies IQ→GPA link)
+
Years of education attained
+
r≈.55-.70
Dropout & Degree Completion
College dropout rate (lower IQ → higher risk)
At IQ 105: ~50% dropout probability (white US sample)
At IQ 130: still ~10% dropout rate
Average undergrad IQ: ~102 today (was ~119 in 1940s)
−0.2 pts/yr
Average PhD holder IQ: ~125
+
SMPY: What Happens to the Gifted?
Top 1% IQ at 12 → 25% earn doctorates (vs 1% general pop)
+
Top 0.5% → 30% earn doctorates
+
Top 0.01% → 50% earn doctorates
+
Lubinski
Linear benefit within gifted range (no ceiling effect)
+
University Selectivity
University SAT ↔ student IQ
+
r=.37
Student IQ range across universities: <100 to >120
~
Bachelor's degree no longer signals above-average IQ
102 avg
33

Sports, Athletics & Competitive Gaming

Mind Sports & Strategy
Esports & Video Games
National mental sport performance ↔ national IQ
+
r=.7912 games
Physical Sports
Wonderlic score ↔ NFL on-field performance
~
<1%null
Physical sport execution (speed, strength-based)
~
negligible
"Sports IQ" (tactical game knowledge) — different from g
~
Cardiovascular fitness ↔ IQ (see §04)
+

The chess meta-analysis (Burgoyne et al., 2016) found an overall correlation of r≈.24 between cognitive ability and chess skill across all samples. The strongest link is with fluid reasoning (Gf), not crystallized knowledge. Critically, the IQ-chess correlation is stronger in young and amateur players and weakens in elite samples — supporting the idea that IQ provides an initial advantage but practice and deliberate training dominate at expert levels. For esports, a study across 12 competitive games (chess, Go, poker, Scrabble, LoL, Dota 2, CS:GO, etc.) found that national IQ predicted top-player representation at r=.79. Physical sports show essentially zero IQ-performance correlation — the Wonderlic test predicts less than 1% of NFL quarterback career performance.

34

Occupational Sorting & Career Patterns

~130
Avg IQ: Professors, Surgeons
~125
Avg IQ: Lawyers, Engineers
~115
Threshold for most professions
~100
Avg IQ: Trades, Machine Operators
Occupational IQ Hierarchy (Approximate Means)
Professors, researchers, scientists
~130-134
Physicians, surgeons
~125-128
Lawyers
~120-128
Engineers (civil, mechanical)
~120-125
Accountants, pharmacists
~117-120
School teachers, nurses
~115-121
Computer programmers
~116-120
Managers, business executives
~112-122
Policemen, clerks, salesmen
~100-110
Machine operators, welders, electricians
~100-105
Laborers, gardeners, factory workers
~90-95
Career Dynamics
Gravitational sorting (high IQ → complex jobs)
+
Job complexity ↔ mean IQ of workers
+
~28 pt gap
IQ predicts job entry but not performance once selected
~
Goleman
IQ ~115 = threshold for most professional work
~
Above threshold, EQ/personality matter more
~
IQ variance within professions is substantial
~
Credentialism inflates some occupational means (e.g., doctors)
~
35

Fertility, Reproduction & Dysgenics

Sensitive
The Dysgenic Pattern
IQ ↔ number of children (negative)
r≈−.05 to −.20
Effect stronger in women than men
+15 IQ pts → 21–25% lower odds of parenthood (women)
Kanazawa
Lifetime childlessness (higher IQ women)
+
Estimated genotypic decline: ~0.6–0.9 IQ pts/generation
Retherford/Sewell
National IQ ↔ national fertility (cross-country)
r=−.73
Mechanisms & Nuances
Mediated primarily by education (path analysis)
~
Higher IQ → later age at first birth → smaller fertility window
"Deficit fertility" — high IQ women want more children than they have
~
Polygenic scores for g negatively predict fertility
genetic
Flynn Effect historically offset genotypic decline
+
Flynn Effect now reversing in some countries (Norway, etc.)
Bratsberg

The paradox: Higher IQ reliably predicts having fewer children. This is one of the most politically toxic findings in the field. The mechanism is not biology — it's that higher IQ delays education, delays marriage, and delays reproduction, compressing the fertility window (especially for women). Polygenic score studies confirm the pattern has a genetic component: alleles associated with higher cognitive ability are becoming less frequent. The Flynn Effect (rising phenotypic IQ from environmental improvements) historically masked this, but the Flynn Effect has now reversed in several countries. Whether this represents a genuine long-term problem depends on contested assumptions about the relative contributions of genetic vs. environmental factors to population-level intelligence.

36

Assortative Mating & Relationships

Spousal IQ Similarity
Spouse IQ correlation (average across studies)
+
r≈.40-.45robust
Comparable to sibling IQ similarity
~
Due to initial selection, not convergence over time
~
Mascie-Taylor
Phenotypic assortment > social homogamy
~
Intelligence is "most important trait" in mate selection surveys
+
IQ assortment accounts for 15–20% of population IQ variance
~
Jensen, 1998
Partner Perception & Illusions
People overestimate own IQ by ~30 pts
+
People overestimate partner IQ by ~36–38 pts
+
Women predict partner IQ with r=.30 accuracy
+
Men predict partner IQ with r=.19 accuracy
+
IQ compatibility ↔ relationship satisfaction
~
≈nullsurprising
IQ tolerance zone: own IQ ±20 points
~
Jensen est.
37

Humor — Expanded

Production vs Appreciation
Humor production (generating original jokes)
+
stronger than appreciation
Humor comprehension (getting the joke)
+
Humor appreciation (rating funniness)
+
weaker
Comedians score higher on verbal IQ than students
+
Greengross
Humor as "heritable fitness indicator" (mate selection)
+
Humor Types by IQ
Sarcasm/irony comprehension
+
Satire appreciation
+
Dark/black humor (Willinger — already covered)
+
Wordplay / puns (verbal IQ loading)
+
Slapstick / physical comedy
~
no link
Gifted children: advanced humor as early identifier
+
Holt, 1995

The production/appreciation split matters. Creating original humor correlates much more strongly with intelligence than simply appreciating it. Greengross & Miller (2011) tested comedians against college students: comedians scored higher on both humor production and verbal IQ. The IQ link is strongest for verbally complex forms — sarcasm, irony, satire, wordplay — and essentially absent for slapstick or physical comedy. Sarcasm comprehension requires cognitive effort to decode the contradiction between literal and intended meaning (Gino, Harvard). Gifted children are consistently identified by teachers as having "advanced humor" — Holt (1995) confirmed gifted students recognize and produce more incongruity-based and wordplay jokes. Humor also functions as a "fitness indicator" in mate selection: both sexes rate funny people as more attractive and more intelligent.

38

Happiness, Life Satisfaction & Wellbeing

The Positive Path
Life satisfaction (positive but mostly indirect)
+
mediated
Lower IQ → lower happiness (clearest at bottom)
N=6,870
Socioeconomic + health factors mediate 50% of link
~
National IQ ↔ happiness inequality (less unequal)
r=−.50
The Dark Side at the Top
More socializing → lower satisfaction in high-IQ (reversed)
Li & Kanazawa
Terman cohort: not happier; same divorce/suicide rates
~
Loneliness ↔ cognitive decline (bidirectional)
Perfectionism → chronic self-disappointment
+
39

Creativity & Divergent Thinking

Intelligence ↔ DT (Meta-Analysis)
Overall correlation (849 effects, N=34,610)
+
r=.25
DT originality scores specifically
+
r≈.31-.37
Threshold theory (IQ ~120 needed, then plateau)
~
debated
g vs Gf vs Gc — no difference in DT correlation
~
Older samples → stronger IQ-creativity link
+
Sarcasm & Abstract Thought
Sarcasm exposure → 3× creative task performance
+
Harvard/Columbia
Irony use ↔ cognitive flexibility + nonverbal IQ
+
Sarcasm exposure: 75% solved task vs 25% control
+
Decoding literal vs intended meaning requires abstraction
+
40

Income vs. Wealth: The Zagorsky Paradox

$234–616
Income per IQ point/year
r=.30
IQ ↔ income
r=.16
IQ ↔ wealth
6%
IQ 125+ maxed credit cards

Zagorsky (2007) — "Your IQ Has No Relationship to Your Wealth"

Using 7,403 participants from the NLSY79 tracked for 25 years: IQ predicts income ($234–616 per IQ point annually, surviving all controls). But IQ→wealth is statistically indistinguishable from zero. People with IQ 105 have higher average net worth than those with IQ 110. Even IQ 125+ individuals report maxing credit cards (6%), missing payments (11%), and filing bankruptcy at non-trivial rates. Smart people earn more but don't keep more.

"If you look at university parking lots, you don't see Rolls Royces. You see old, low-value vehicles." — Jay Zagorsky, Ohio State. The skills that generate income (reasoning, verbal ability) are not the skills that generate wealth (frugality, patience, impulse control).

41

Temporal Discounting & Future Orientation

Delay Discounting
Steeper temporal discounting (lower IQ = more impatient)
replicated
IQ-discounting link exceeds personality or other cognitive variables
+
Genetic overlap: discounting ↔ childhood IQ (GWAS)
rg=−.63genetic
Genetic overlap: discounting ↔ years of education
rg=−.67
High IQ + steep discounting → alcohol problems
+
paradox
Future Time Perspective
Future time perspective ↔ delay of gratification
+
Episodic future thinking (mental time travel)
+
Date framing reduces discounting vs delay framing
~
Marshmallow test predictive power (partly an IQ proxy)
+
weaker replications
Self-control peaks in middle adulthood (U-curve across lifespan)
~

The genetic evidence is striking: Sanchez-Roige et al. (2018) found via GWAS that the genetic signature of temporal discounting overlaps with childhood IQ at rg=−.63 and with college attainment at rg=−.93. This means the genes that make you impatient with future rewards substantially overlap with the genes that lower cognitive ability. The IQ-discounting correlation exceeds the correlation of discounting with any personality trait. The marshmallow test's predictive power, once thought to reflect pure self-control, is now understood as partly an IQ test in disguise — children who wait longer tend to be smarter, and the cognitive ability partly drives both the waiting and the later life outcomes.

42

Impostor Syndrome & Self-Perception

Impostor Phenomenon
Impostor feelings prevalent in high-achieving populations
+
Impostor ↔ maladaptive perfectionism (strong link)
+
Impostor ↔ neuroticism (strongest Big Five predictor)
+
Two responses: over-preparation OR procrastination
+
Gifted children: early awareness of being "different"
+
Self-Estimation of IQ
Men overestimate own IQ (~5 pts)
+
Women underestimate own IQ
Partners overestimate each other's IQ (+36-38 pts!)
+
Gignac
Dunning-Kruger: low performers overestimate most
High performers slightly underestimate (false consensus)

The impostor-IQ link is indirect but powerful: Impostor syndrome is not caused by high IQ per se, but it concentrates in high-achieving populations where IQ tends to be elevated. The core mechanism: high standards (from genuine competence) + maladaptive perfectionism + attribution of success to luck rather than ability = chronic self-doubt despite objective evidence of capability. Clance & Imes (1978) first described this in high-achieving women. It intensifies during transitions (starting university, new job, promotion) — precisely when high-ability people first encounter cognitive peers and lose the "smartest in the room" identity formed in childhood. The over-preparation/procrastination split maps onto two coping responses: working obsessively to prevent exposure, or delaying to have an excuse for imperfection.

43

Morality, Fairness & Prosocial Behavior

Moral Reasoning
Kohlberg moral reasoning stage
+
Utilitarian moral judgments (trolley-type problems)
+
Moral complexity tolerance (rejecting black/white)
+
Charitable giving (after controlling for income)
~
≈flat
Prosocial Behavior
Strategic cooperation (see §24)
+
Fair offers in ultimatum games
+
Volunteering / civic participation
+
Voter turnout
+
The Manipulation Side
Machiavellianism (strategic social manipulation)
~
r≈.00
Psychopathy (no IQ correlation at population level)
~
r≈.00
White-collar crime (IQ needed for opportunity)
+
Sophisticated rationalization of unethical behavior
+
44

College Majors & Fields of Study

~133
Physics & Astronomy
~130
Mathematical Sciences
~129
Philosophy
~102
Education / Early Childhood
Estimated IQ by Major (GRE/SAT-Derived)
Physics & Astronomy
~133
Mathematical Sciences
~130
Philosophy
~129
Materials Engineering
~129
Economics
~128
Computer Science
~124
Chemistry / Biological Sciences
~120-124
Political Science / History
~115-120
Psychology / Sociology
~110-115
Business / Administration
~108-112
Education / Early Childhood
~102-105
Key Patterns
STEM fields ↔ highest composite scores
+
Physics top on BOTH verbal + quantitative
+
unique
Philosophy: top verbal, above-average quantitative
+
Education: ~1 SD below Physics on both GRE sections
~16 pts gap
Quantitative SAT ↔ gender ratio (R²=.74; fewer women)
Olson
Within-major variance > between-major variance
~
caveat

The SAT/GRE-to-IQ conversion caveat: These estimates are derived from standardized test scores (GRE, SAT) converted to IQ equivalents using established correlations (SAT↔IQ r≈.80; GRE↔IQ r≈.70). The key finding is that Physics students are uniquely dominant — they score highest on both verbal and quantitative sections, not just math. Philosophy students rank near the top on verbal (often #1 or #2) and above average on quantitative, making them the strongest "verbal intelligence" field. The ~16-point IQ gap between Education and Math/Statistics majors (Wai & Kanaya, 2024) is striking and has implications for whether societies draw teachers from their highest-ability pools. The Olson analysis found that the apparent "IQ" ranking of majors is driven almost entirely by quantitative SAT scores (R²=.74), not verbal, which means these rankings partly reflect preference for quantitative work rather than overall cognitive ability.

45

Lucid Dreaming, Metacognition & Insight

Emerging
Lucid Dreaming
Lucid dreamers: larger anterior prefrontal cortex
+
MPI Berlin
Lucid dreamers: higher waking metacognitive ability
+
Lucid dreamers: 25% more insight puzzles solved
+
Bourke & Shaw
Lucid dreamers: better reality monitoring
+
Lucid dreaming ↔ IQ (direct correlation)
~
not established
Metacognition & Self-Reflection
Metacognitive monitoring accuracy ↔ IQ
+
Anterior prefrontal cortex volume (shared substrate)
+
Self-reflection in everyday life (lucid dreamers higher)
+
Dream bizarreness awareness ↔ cognitive flexibility
+
Conflict resolution efficiency ↔ trait lucidity
+

The link is metacognition, not IQ directly. Filevich et al. (2015, Max Planck) found that frequent lucid dreamers have larger anterior prefrontal cortex volume and show higher prefrontal activation during metacognitive tasks while awake. Bourke & Shaw found lucid dreamers solve 25% more insight problems. The connection to intelligence is indirect but structurally grounded: the same brain region (BA9/10) supports both lucid dreaming and metacognitive monitoring, and metacognition correlates with fluid intelligence. No study has found a direct IQ↔lucid dreaming frequency correlation, but the shared neural substrate suggests intelligence, lucid dreaming, and metacognition share common biological infrastructure.

46

Romance, Dating & Mate Selection

Assortative Mating
Spousal IQ correlation (strongest trait after attitudes)
+
r≈.40-.45Jensen
Cognitive ability: among strongest mating assortment variables
+
Initial assortment (not convergence over time)
+
Mascie-Taylor
Cross-trait: women's attractiveness → husband's IQ
+
Cross-trait: men's attractiveness → wife's IQ (no link)
~
≈null
What People Want vs What They Choose
Women state preference for intelligence (strong)
+
Men state preference for attractiveness (strong)
+
Stated preferences ↔ actual choices (poor match!)
~
speed-dating
Speed-dating: men chose on looks, women on total package
~
Both sexes reject less intelligent mates
More intelligent than you ≠ more desirable than equally intelligent
~
ceiling
Relationship Outcomes
IQ-matched couples: more stable marriages
+
Partners overestimate each other's IQ (+36-38 pts)
+
Gignac
Humor production as fitness indicator in mate selection
+
Large IQ gap within couple → lower satisfaction
clinical
Genetic influence on mate choice ≈ zero
~
Zietsch N>20K

The cross-trait mating finding: Physically attractive women tend to marry more intelligent men, but physically attractive men do NOT marry more intelligent women. This asymmetry reflects sexual strategies theory — women can "trade" attractiveness for male intelligence/resources, but the reverse trade is weaker. Both sexes use a "likes-attract" rule (prefer similar IQ), but reject less intelligent mates more strongly than they prefer more intelligent ones. Intelligence above your own level is not more attractive — it just needs to be "enough." Speed-dating research (PNAS, 2007) showed that people's stated preferences barely predict their actual choices — men chose on looks regardless of what they said; women were more selective overall but chose on "total package" rather than any single trait.

47

Economics, Sociology & Public Policy

National / Macro-Level
National IQ ↔ GDP per capita
+
r≈.70Lynn/Vanhanen
National IQ ↔ economic growth (Bayesian robust)
+
Jones/Schneider
National IQ ↔ institutional quality / rule of law
+
National IQ ↔ happiness inequality (lower)
r=−.50
Smart fraction theory (top 5% drives national innovation)
+
Individual-Level Sociology
IQ ↔ social mobility (upward)
+
IQ ↔ civic participation / voting
+
IQ ↔ welfare dependency (negative)
Non-cognitive skills compensate for lower IQ (Heckman)
~
Nobel
Conscientiousness → grades: nearly as strong as IQ
+
Poropat
Scandinavian Conscript Data (Beyond Sweden)
Norwegian conscripts: Flynn effect reversed post-1975
Bratsberg
Danish conscripts: infection → −1.76 IQ pts
Finnish conscripts: IQ → stock market behavior (§23)
+
Norwegian reversal: environmental, not genetic
~
within-family
Norwegian schooling reform → IQ gain (causal)
+
+1-5 pts
German-Language Findings (Translated)
GMA → job performance (German meta): r≈.30-.50
+
DIW/SOEP: personality + IQ jointly predict education
+
Non-cognitive traits boost cognitive development (Cunha & Heckman)
+
causal
BIS model (Jäger): g = integral of cognitive abilities
+
Reaction time ↔ IQ (Neubauer, Austrian data)
Neubauer
48

Games, Hobbies & Leisure — Expanded

Board & Card Games
Chess ↔ IQ (meta-analysis, youth strongest)
+
r≈.24
Go (weaker than chess; pattern over calculation)
+
Bridge (bidding = Bayesian inference under uncertainty)
+
Poker (probability + opponent modeling + EQ)
+
Scrabble (vocabulary + board strategy)
+
Video Games (Expanded)
MOBA (LoL, Dota 2) rank ↔ Gf
+
r≈.30-.40
RTS (StarCraft) ↔ cognitive speed + multitasking
+
Puzzle games (Portal, The Witness) ↔ spatial IQ
+
Complex simulation games (Factorio, KSP)
+
anecdotal
FPS/action (reflex-dominant) ↔ IQ
~
weak
Total gaming hours ↔ IQ (flat — genre matters, not time)
~
Leisure & Consumption
Preference for complex narrative (books, film, TV)
+
Wikipedia editing and knowledge contribution
+
proxy
Crossword / Sudoku / logic puzzle engagement
+
Reality TV watching
anecdotal
Documentary preference
+
Podcast listening (long-form informational)
+
proxy
49

Military, Armed Forces & Combat

Training & Job Performance
ASVAB ↔ IQ correlation
+
r≈.80-.90
AFQT → training success (corrected)
+
r≈.60
AFQT → hands-on job proficiency (HOPT)
+
ρ=.44Cucina 2024
Aptitude area score → HOPT (job-family specific)
+
ρ=.55
High-ability recruits learn 2-5× faster in training
+
Validity stable across experience levels (no decay)
+
Officer Selection & Leadership
WWI: 1.5M recruits tested; A/B grades → officer candidates
+
WWII AGCT: 12M recruits; classification by cognitive grade
+
U.S. officers avg IQ: ~108-115 (0.5-1.0 SD above pop)
+
Senior generals/admirals: estimated ~115-130
+
Minimum AFQT for enlistment ≈ IQ 83
U.S. law bars enlistment of bottom 10% (IQ <83)
policy

The Military as the World's Largest IQ Dataset

The U.S. military has tested more people's cognitive ability than any other institution in history — 1.5 million in WWI, 12 million in WWII, and roughly 1 million per year today via the ASVAB. The ASVAB correlates .80–.90 with standard IQ tests and predicts hands-on job proficiency at ρ=.44–.55 (Cucina et al., 2024) — notably higher than the civilian job performance estimates currently under debate (ρ=.22–.51). The military finding is stronger because the criterion (actually performing job tasks under observation) is more objective than civilian supervisory ratings.

Policy implication: U.S. law (10 U.S.C. §520) prohibits enlistment of individuals scoring below the 10th percentile on the AFQT (~IQ 83). This is one of the few public policies worldwide that explicitly uses cognitive ability as a legal threshold. The 1991 Gulf War demonstrated that units with higher average AFQT scores performed measurably better in combat effectiveness metrics.

50

Consumer Behavior, Marketing & Persuasion

Purchasing & Decision-Making
Resistance to advertising persuasion techniques
+
Scarcity/urgency heuristic susceptibility
Product research depth before purchasing
+
Comparison shopping / price sensitivity
+
Susceptibility to financial scams
~
complex ↔ sophistication
Brand & Loyalty
Cognitive (vs emotional) brand evaluation
+
Brand loyalty based on quality assessment (not habit)
+
Older consumers: affect > cognition in loyalty
Willingness to pay premium for quality (high-price items)
+
Management & Organization
Managerial cognitive ability → team performance
+
CEO IQ → firm performance (curvilinear — see §24)
~
1.2 SD optimum
EQ > IQ for management success (once IQ ≥ 115)
~
Goleman
Cognitive ability 5× more predictive than EQ (sales)
+
Grant
Entrepreneurship: IQ helps entry, personality drives success
~

The IQ vs EQ debate in business, resolved: Both matter, but for different things. Adam Grant's study of sales performance found cognitive ability was 5× more predictive than emotional intelligence — higher-ability salespeople generated $195K annual revenue vs $109K for lower-ability ones, and EQ added nothing after controlling for cognitive ability. But Goleman's framework holds for management: once you're above the ~115 IQ threshold needed to enter a profession, emotional intelligence, social skills, and drive determine who rises. The "three-factor model" (cognitive ability + social skills + drive) is "fundamentally compensatory" — exceptional social skills can partially offset average IQ. The military data confirms this: officer promotion beyond lieutenant depends more on leadership and political skill than raw cognitive ability.

51

Specific Policy Views & Moral Attitudes

Intelligence interacts with ideology in complex ways. Verbal IQ is ~2× stronger than performance IQ in predicting political attitudes (Edwards et al., 2024). The "argument advantage" model (PNAS Nexus, 2023) explains why: higher verbal ability helps people understand whichever side has stronger arguments in public discourse, regardless of left/right framing.
Higher IQ → More Support
Gay marriage / LGBTQ+ rights
+
Free speech protections
+
Drug legalization / marijuana
+
Deregulation / free markets
+
libertarian
Euthanasia / right to die
+
Higher IQ → Less Support
Death penalty
Strict immigration restrictions
Authoritarianism
strongest
Censorship
Prayer in schools / theocracy
Complex / Context-Dependent
Gun control
~
anti-reg
Abortion
+
argument-adv
Economic conservatism
~
two pathways
Context-dependent: IQ tracks prevailing intellectual norms
~
52

Drink & Food Preferences

Beverage Preferences
Wine preference over beer/spirits
+
OR=2.8Danish
Wine drinking ↔ education + income
+
Perceived IQ drops when seen drinking alcohol
imbibing idiot
Coffee consumption
~
weak
Food Preferences
Vegetarianism (childhood IQ → adult choice)
+
OR=1.38
Higher dietary quality score
+
Preference for novel / exotic cuisine
+
Kanazawa
Fruit and vegetable consumption
+
bidirectional
53

Social Dynamics, Hierarchy & Group Behavior

Status & Hierarchy
Status attainment in groups
+
Occupational prestige attainment
+
Social dominance orientation
Strategic social calibration in groups
+
Interpersonal Dynamics
Socializing frequency → satisfaction (inverted for high IQ)
Cognitive empathy (theory of mind)
+
Processing speed → social misalignment
+
Manipulation detection (simple: better; complex: paradox)
~
Conflict & Communication
Argument sophistication (but not fairness)
+
Winning arguments at relationship cost
+
clinical
Preference for deep over wide social networks
+
54

Emotional Intelligence, Affect & Inner Life

EQ vs IQ
Ability-based EI ↔ IQ (moderate positive)
+
r≈.20-.30
Self-report EI ↔ IQ (near zero)
~
r≈.00
EQ vs IQ for job performance (depends on role)
~
Emotion perception loads on g; emotion management does not
~
Emotional Intensity & Regulation
Dabrowski overexcitability (emotional intensity)
+
Karpinski
Rumination / overthinking
+
Worry about abstract / distal threats
+
Cognitive reappraisal ability
+
55

Crowd-Sourced, Novel & Contested Findings

Sources: ClearerThinking.org empirical study (N=3,691, 40 IQ claims tested, 62 intelligence tasks, 2024–2025), Reddit/Twitter discussions, and notable skeptical critiques.
ClearerThinking.org Study (N=3,691)
Higher IQ → better time-use alignment with ideals
+
IQ predictive across full distribution (not just left tail)
+
refutes Taleb
Higher IQ → less confident about solving societal problems
Dunning-Kruger
IQ ↔ perfectionism (no correlation — myth busted)
~
r≈.00
IQ → high school grades (stronger than college grades)
+
Positive manifold confirmed (62 diverse tasks)
+
IQ ↔ actively open-minded thinking (r=.43 — strongest)
+
r=.43ClearerThinking
65% of Americans think they are above-average intelligence
+
Men overestimate IQ by 5-15 pts; women underestimate
~
The Skeptics: Taleb & Critics
Taleb: IQ is 'pseudoscientific swindle'
polemic
Fat tails argument: correlations inflate in-sample
~
Richardson: IQ-job validity is methodological artifact
Brown, Wai & Chabris rebuttal (2025)
~
disputed
Music training → IQ: genetic confounder (myth busted)
~
10,500 twins
Reddit / Twitter / Forum-Sourced
Social alienation in group settings (self-reported)
+
anecdotal
IQ tests feel easier after college (self-reported)
+
anecdotal
Gifted kid burnout / underachievement pattern
+
anecdotal
Public intellectual IQ estimates (Kirkegaard, N=584)
~
poll
Aella Chaos Survey (tech/rationalist demographics)
~
self-selected
Classical music ↔ IQ: disappears after SES controls
~
confounded
Expert survey on IQ: field is 83% male, 54% liberal
~
Methodological Cautions
All IQ correlations are ~20% attenuated by measurement error
~
Large N makes tiny correlations 'significant' (be cautious)
~
Within-group variance > between-group variance (always)
~
critical
Absence of correlation ≠ absence of relationship
~
From Substack & Medium
Positive manifold weakening over time (Oberleiter 2024)
new
IQ ↔ toxicity (r≈-.15 to -.20)
Self-assessed IQ ↔ actual IQ (r=.30, meta-analysis)
+
Extraversion 'activity' facet → positive IQ link
+
Neuroscience & Positive Psychology
Mutualist model: g as emergent network
~
Growth mindset: real but small effect (d≈.08)
+
overhyped
Brain criticality and cognitive optimization
~
theoretical
Neuroplasticity: real but limited transfer
~
Dunedin Study (N=1,037, birth→age 52)
Childhood IQ → pace of biological aging
+
longitudinal
Brain-age at 45: ranges 24-72 yrs (linked to childhood IQ)
+
β=−.17
Early death (before 45) → lower childhood IQ (p=.04)
mortality
Childhood lead → IQ loss + lower SES at age 38
JAMA
Japanese & East Asian Cognitive Science
Flynn effect in Japan: now plateauing/reversing
Cognitive function → work performance (Japanese data)
+
56

Harvard Grant Study & Longitudinal Life Outcomes

The world's longest longitudinal study of adult development. 268 Harvard sophomores followed from 1938 to present (85+ years). Vaillant (1977, 2002) directed the study for decades; Waldinger & Schulz continue it today. Key finding: warm relationships, not IQ, are the #1 predictor of healthy aging.
IQ vs Other Predictors
IQ did NOT predict life satisfaction (defenses did)
~
85-year study
Mature defense mechanisms > IQ for life outcomes
~
Warm relationships > IQ for health at age 80
~
Waldinger
IQ-matched men diverged based on coping style
~
Education predicts aging beyond IQ and SES
+
PsyPost & Recent Findings (2024-2025)
Childhood IQ ↔ longevity: shared genetics (rg=.35)
+
genetic
Higher IQ → more accurate lifespan predictions
+
Genetic link: higher IQ ↔ sexlessness (GWAS)
+
UK Biobank
Gifted are NOT hyper-empathic (myth challenged)
~
2025 review
IQ readable from male faces, not female faces
+
men only
Polygenic scores predict IQ at r≈.25
+
57

Public Intellectuals & Commentary on IQ

Rob Henderson
Social norms compensate for lower IQ
~
Luxury beliefs: IQ enables elite rationalization
+
Lower IQ → stronger parasocial celebrity beliefs
IQ shredders: cities attract smart non-reproducers
Steve Stewart-Williams
Better schools → wider ability gaps (not narrower)
+
Intelligent people are equally prejudiced (different targets)
~
Compassion ↔ IQ positive; politeness ↔ IQ negative
~
PNAS
Specific abilities genetically independent of g
+
747K twins
Psychology Today & Popular Science
Twins apart converge; unrelated siblings diverge
+
twin study
Genes boosting IQ simultaneously reduce psychopathology
+
Military members are smarter than civilian peers
+
IQ is necessary but not sufficient (Warne)
~

58

References & Key Sources

Selected primary sources for claims made in this document. Ordered by topic. Effect sizes and r-values in the document are rounded. Full texts available via DOI or PubMed. Where findings are contested, multiple sources are listed. The "2025 job performance" finding should be treated as preliminary pending full peer review.
Cognitive & Brain

Sheppard, L.D., & Vernon, P.A. (2008). Intelligence and speed of information-processing: A review of 50 years of research. Personality and Individual Differences, 44(3), 535–551.

Pietschnig, J., et al. (2015). Meta-analytic investigation of the relationship between brain volume and intelligence. Neuroscience & Biobehavioral Reviews, 55, 254–294.

Haier, R.J., et al. (1988). Cortical glucose metabolic rate correlates of abstract reasoning and attention studied with positron emission tomography. Intelligence, 12(2), 199–217. [Neural efficiency hypothesis]

Shaw, P., et al. (2006). Intellectual ability and cortical development in children and adolescents. Nature, 440(7084), 676–679.

Gignac, G.E., & Bates, T.C. (2017). Brain volume and intelligence: The moderating role of intelligence measurement quality. Intelligence, 64, 18–29.

Personality

Ackerman, P.L., & Heggestad, E.D. (1997). Intelligence, personality, and interests: Evidence for overlapping traits. Psychological Bulletin, 121(2), 219–245.

DeYoung, C.G., et al. (2014). Openness to experience, intellect, and cognitive ability. Journal of Personality Assessment, 96(1), 46–52.

Furnham, A. (2001). Self-estimates of intelligence: Culture and gender difference in self and other estimates of both general (g) and multiple intelligences. Personality and Individual Differences, 31(8), 1381–1405.

Charlton, B.G. (2009). Clever sillies: Why high IQ people tend to be deficient in common sense. Medical Hypotheses, 73(6), 867–870.

Physical & Body

Rasmussen, L.J.H., et al. (2019). Association of neurocognitive and physical function with gait speed in midlife. JAMA Network Open, 2(10), e1913123. [Walking speed + IQ, 45-year-olds, r=.38]

Ball, H., et al. (2024). Adolescent IQ and performance-based measures of physical function in old age: a 54-year longitudinal study. Journals of Gerontology: Series B, 80(10). [Grip, lung capacity]

Ntolka, E., & Papadatou-Pastou, M. (2018). Right-handers have negligibly higher IQ scores than left-handers: Systematic review and meta-analyses. Neuroscience & Biobehavioral Reviews, 84, 376–393.

Saw, S.M., et al. (2004). IQ and the association with myopia in children. Investigative Ophthalmology & Visual Science, 45(9), 2943–2948.

Williams, K.M., et al. (2017). Phenotypic and genotypic correlation between myopia and intelligence. Scientific Reports, 7, 45977.

Kanazawa, S. (2011). Intelligence and physical attractiveness. Intelligence, 39(1), 7–14. [UK NCDS, r=.38]

Mitchem, D.G., et al. (2015). No relationship between intelligence and facial attractiveness in a large, genetically informative sample. Evolution and Human Behavior, 36(3), 240–247. [Null result, twin study]

Sleep & Chronotype

Preckel, F., et al. (2011). Chronotype, cognitive abilities, and academic achievement: A meta-analytic investigation. Learning and Individual Differences, 21(5), 483–492. [r=.08 eveningness/IQ]

Piffer, D., et al. (2014). Night owls have higher GMAT scores than early morning types in a top-ranked MBA program. Intelligence, 47, 107–112.

West, R., & Ma, D. (2024). Sleep duration, chronotype, health and lifestyle factors affect cognition: A UK Biobank cross-sectional study. BMJ Public Health. DOI:10.1136/bmjph-2024-001000. [N=26,000; night owls 7–13.5% higher scores]

Kanazawa, S., & Perina, K. (2009). Why night owls are more intelligent. Personality and Individual Differences, 47(7), 685–690. [Savanna-IQ hypothesis]

Giampietro, M., & Cavallera, G.M. (2007). Morning and evening types and creative thinking. Personality and Individual Differences, 42(3), 453–463.

Lifestyle — Alcohol, Smoking, Exercise

Sjölund, S., et al. (2015). IQ and level of alcohol consumption — findings from a national survey of Swedish conscripts. Alcoholism: Clinical and Experimental Research, 39(3), 548–555.

Batty, G.D., et al. (2018). Intelligence in youth and health behaviours in middle age. Intelligence, 69, 71–78. [National Longitudinal Survey; alcohol, smoking, exercise, diet]

Davies, N.M., et al. (2019). Within-family Mendelian randomization study of education and alcohol consumption. European Journal of Epidemiology, 34, 741–750.

Liu, X., et al. (2023). Can intelligence affect alcohol-, smoking-, and physical activity-related behaviors? A Mendelian randomization study. Journal of Intelligence, 11(2), 29.

Åberg, M.A.I., et al. (2009). Cardiovascular fitness is associated with cognition in young adulthood. PNAS, 106(49), 20906–20911. [Swedish conscripts; fitness → IQ, university]

Gale, C.R., et al. (2007). IQ in childhood and vegetarianism in adulthood: 1970 British cohort study. BMJ, 334(7587), 245. [OR=1.38 per SD IQ]

Health, Mental Health & Immune

Calvin, C.M., et al. (2017). Childhood intelligence in relation to major causes of death in 68 year follow-up: prospective population study. BMJ, 357, j2708.

Deary, I.J., et al. (2010). The neuroscience of human intelligence differences. Nature Reviews Neuroscience, 11(3), 201–211.

Karpinski, R.I., et al. (2018). High intelligence: A risk factor for psychological and physiological overexcitabilities. Intelligence, 66, 8–23. [MENSA study, N=3,715; allergies, anxiety, ADHD]

Maier, S.J., et al. (2023). High intelligence is not associated with a greater propensity for mental health disorders. European Psychiatry, 66(1). [UK Biobank, N=261,701; replication/rebuttal of Karpinski]

Benrós, M.E., et al. (2015). Infections can affect cognitive ability — the largest study of its kind. Aarhus University / PLOS ONE. [Hospitalization from infection: −1.76 IQ pts]

Social, Sexual & Life History

Halpern, C.T., et al. (2000). Smart teens don't have sex (or kiss much either). Journal of Adolescent Health, 26(3), 213–225.

Harden, K.P., & Mendle, J. (2011). Why don't smart teens have sex? A behavioral genetic approach. Child Development, 82(3), 1026–1040.

Li, N.P., & Kanazawa, S. (2016). Country roads, take me home… to my friends: How intelligence, population density, and friendship affect modern happiness. British Journal of Psychology, 107(4), 675–697. [High IQ + solitude + satisfaction]

Kanazawa, S. (2010). Why more intelligent people are more likely to be liberal, atheist, and sexually exclusive. Social Psychology Quarterly, 73(1), 33–57.

Lead, Iodine & Environmental Causation

Lanphear, B.P., et al. (2005). Low-level environmental lead exposure and children's intellectual function: An international pooled analysis. Environmental Health Perspectives, 113(7), 894–899. [N=1,333; no safe threshold]

Needleman, H.L., et al. (1990). The long-term effects of exposure to low doses of lead in childhood. New England Journal of Medicine, 322(2), 83–88.

Feyrer, J., Politi, D., & Weil, D.N. (2017). The cognitive effects of micronutrient deficiency: Evidence from salt iodization in the United States. Journal of the European Economic Association, 15(2), 355–387. [Historic natural experiment]

Zimmermann, M.B. (2009). Iodine deficiency. Endocrine Reviews, 30(4), 376–408.

Mani, A., et al. (2013). Poverty impedes cognitive function. Science, 341(6149), 976–980. [Bandwidth tax ≈ −13 IQ pts functional]

Reyes, J.W. (2007). Environmental policy as social policy? The impact of childhood lead exposure on crime. B.E. Journal of Economic Analysis & Policy, 7(1). [Lead removal → crime decline]

Nutrition & Developmental

Caspi, A., et al. (2007). Moderation of breastfeeding effects on the IQ by genetic variation in fatty acid metabolism. PNAS, 104(47), 18860–18865. [FADS2 gene; +6.8 IQ pts in C-carriers]

Victora, C.G., et al. (2015). Association between breastfeeding and intelligence, educational attainment, and income at 30 years of age: A prospective birth cohort study. Lancet Global Health, 3(4), e199–e205. [Brazil; +4 IQ pts at 30 years]

Damian, R.I., & Roberts, B.W. (2015). The associations of birth order with personality and intelligence in a representative sample of US high school students. Journal of Research in Personality, 58, 96–105. [N=377,000; +1 IQ pt firstborn]

Grantham-McGregor, S., & Ani, C. (2001). A review of studies on the effect of iron deficiency on cognitive development in children. Journal of Nutrition, 131(2), 649S–668S.

Vocational Interests & RIASEC

Ackerman, P.L., & Heggestad, E.D. (1997). Intelligence, personality, and interests: Evidence for overlapping traits. Psychological Bulletin, 121(2), 219–245. [RIASEC × IQ; foundational meta-analysis]

Stanek, K.C., & Ones, D.S. (2023). Meta-analytic relations between personality and cognitive ability. PNAS, 120(23), e2212794120. [60,690 relations; 3,543 meta-analyses; millions of participants; facet-level analysis]

Denissen, J.J.A., et al. (2011). Predicting adult occupational environments from gender and childhood personality traits. Journal of Applied Psychology, 96(1), 155–165. [40-year longitudinal; Openness → Investigative/Artistic occupations]

Bergold, S., & Steinmayr, R. (2015). Interests and intelligence: A meta-analysis. Intelligence, 50, 154–167. [N=55,297; RIASEC × g meta-analysis]

Edwards, T., et al. (2024). Predicting political beliefs with polygenic scores for cognitive performance and educational attainment. Intelligence, 104, 101831. [Within-family causal design; verbal IQ 2× stronger than performance IQ]

Personality Facets & Quirks

Stanek, K.C., & Ones, D.S. (2023). Meta-analytic relations between personality and cognitive ability. PNAS, 120(23), e2212794120. [Compassion r=.26; politeness r=−.22; activity facet r=.25; industriousness r=.32; depression facet → lower IQ]

Jay, T., & Janschewitz, K. (2015). Taboo word fluency and knowledge of slurs and general pejoratives: Deconstructing the poverty-of-vocabulary myth. Language Sciences, 52, 251–259. [Swearing fluency = verbal fluency; Jay's 40-year corpus of swearing research]

Vohs, K.D., et al. (2013). Physical order produces healthy choices, generosity, and conventionality, whereas disorder produces creativity. Psychological Science, 24(9), 1860–1867. [Messy desk → more creative ideas]

Andrade, J. (2010). What does doodling do? Applied Cognitive Psychology, 24(1), 100–106. [Doodling → 29% better recall, N=40]

Willinger, U., et al. (2017). Cognitive and emotional demands of black humour processing: The role of intelligence, aggressiveness and mood. Cognitive Processing, 18(2), 159–167. [Dark humor + high verbal and nonverbal IQ]

Gers, T., et al. (2023). The relation of personality and intelligence: What can the Brunswik symmetry principle tell us? Journal of Intelligence, 7(2). [Facet-level Openness × verbal reasoning: Ideas facet strongest link]

Social Impressions

Luftig, R.L., & Nichols, M.L. (1990). Assessing the social status and peer relationships of learning disabled students in mainstreamed settings. Learning Disability Research, 5(1), 3–10. [Gifted label → friendship difficulties]

Borkenau, P., et al. (2004). A process model of the perception of personality. Psychological Review, 111(3), 764–778. [First impressions; accuracy vs. bias in intelligence judgments]

Kleisner, K., et al. (2014). Perceived intelligence is associated with measured intelligence in men but not women. PLOS ONE, 9(3), e81237. [Face-based intelligence accuracy; male only]

Bailey, R.C., DiGiacomo, R.J., & Zinser, O. (1976). Length of male and female friendship and perceived intelligence in self and friend. Journal of Personality Assessment, 40, 635–640. [Perception of intelligence in close relationships]

Proyer, R.T., et al. (2012). Positive perception of others by individuals with high intelligence: Evidence for a more prosocial orientation. Personality and Individual Differences, 52, 669–673.

Kanazawa, S., & Perina, K. (2012). Why more intelligent individuals like classical music. Journal of Behavioral Decision Making, 25(3), 264–275. [N=1,500; instrumental preference → IQ]

Rentfrow, P.J., & Gosling, S.D. (2003). The do re mi's of everyday life: The structure and personality correlates of music preferences. Journal of Personality and Social Psychology, 84(6), 1236–1256.

Willinger, U., et al. (2017). Cognitive and emotional demands of black humour processing: The role of intelligence, aggressiveness and mood. Cognitive Processing, 18(2), 159–167. [Dark humor + IQ]

Waters, A.J., et al. (2015). Chess skill and working memory. Intelligence, 49, 95–100. [Chess ↔ IQ, r≈.25-.35]

Schellenberg, E.G. (2004). Music lessons enhance IQ. Psychological Science, 15(8), 511–514. [+3 IQ pts piano/voice at age 6]

Politics, Religion & Values

Lynn, R., Harvey, J., & Nyborg, H. (2009). Average intelligence predicts atheism rates across 137 nations. Intelligence, 37(1), 11–15. [r≈−.20-.24 religiosity/IQ]

Souza, G.H.S., & Cribari-Neto, F. (2015). Intelligence, religiosity and homosexuality non-acceptance: Empirical evidence. Intelligence, 52, 63–70. [National IQ ↔ acceptance, r=−.58]

Kemmelmeier, M. (2008). Is there a relationship between political orientation and cognitive ability? A test of three hypotheses in two studies. Personality and Individual Differences, 45(8), 767–772.

Stankov, L. (2009). Conservatism and cognitive ability. Intelligence, 37(3), 294–304.

Meta, Flynn Effect & Job Performance

Flynn, J.R. (2007). What Is Intelligence?: Beyond the Flynn Effect. Cambridge University Press.

Bratsberg, B., & Rogeberg, O. (2018). Flynn effect and its reversal are both environmentally caused. PNAS, 115(26), 6674–6678. [Norwegian reversal]

Schmidt, F.L., & Hunter, J.E. (1998). The validity and utility of selection methods in personnel psychology. Psychological Bulletin, 124(2), 262–274. [Classic r=.51 job performance estimate]

Steel, P., & Fariborzi, H. (2025). Strong decrease in predictive validity of IQ tests for work performance. Discussed in Progress Focused (July 2024). [Revised to r≈.16; Steel & Fariborzi, 2025 — note: prelim, confirm publication details]

Strenze, T. (2007). Intelligence and socioeconomic success: A meta-analytic review of longitudinal research. Intelligence, 35(5), 401–426. [IQ → income, r≈.30-.40]

Bouchard, T.J. Jr. (2013). The Wilson Effect: The increase in heritability of IQ with age. Twin Research and Human Genetics, 16(5), 923–930. [Adult heritability ≈ .80]

Deary, I.J. (2012). Intelligence. Annual Review of Psychology, 63, 453–482. [System integrity hypothesis]

Rationality, Biases & Dysrationalia

Stanovich, K.E., West, R.F., & Toplak, M.E. (2013). Myside bias, rational thinking, and intelligence. Current Directions in Psychological Science, 22(4), 259–264. [Myside bias r≈.00 with IQ]

Stanovich, K.E. (2009). What Intelligence Tests Miss: The Psychology of Rational Thought. Yale University Press.

Stanovich, K.E. (2021). The Bias That Divides Us: The Science and Politics of Myside Thinking. MIT Press.

Frederick, S. (2005). Cognitive reflection and decision making. Journal of Economic Perspectives, 19(4), 25–42. [CRT; r≈.40-.50 with IQ]

West, R.F., Meserve, R.J., & Stanovich, K.E. (2012). Cognitive sophistication does not attenuate the bias blind spot. Journal of Personality and Social Psychology, 103(3), 506–519.

Financial & Economic Behavior

Grinblatt, M., Keloharju, M., & Linnainmaa, J.T. (2011). IQ and stock market participation. Journal of Finance, 66(6), 2121–2164. [N≈160,000 Finnish males; 20% participation gap]

Grinblatt, M., Keloharju, M., & Linnainmaa, J.T. (2012). IQ, trading behavior, and performance. Journal of Financial Economics, 104(2), 339–362. [High-IQ: less disposition effect, better Sharpe ratios]

Agarwal, S., & Mazumder, B. (2013). Cognitive abilities and household financial decision making. American Economic Journal: Applied Economics, 5(1), 193–207.

Cooperation & Game Theory

Proto, E., Rustichini, A., & Sofianos, A. (2019). Intelligence, personality, and gains from cooperation in repeated interactions. Journal of Political Economy, 127(3), 1351–1390.

Proto, E., Rustichini, A., & Sofianos, A. (2022). Intelligence, errors and strategic choices in the repeated prisoners' dilemma. Review of Economic Studies. [High-IQ groups converge to full cooperation; replicated 2025]

Jones, G. (2008). Are smarter groups more cooperative? Evidence from prisoner's dilemma experiments, 1959–2003. Journal of Economic Behavior & Organization, 68(3-4), 489–497.

Antonakis, J., House, R.J., & Simonton, D.K. (2017). Can super smart leaders suffer from too much of a good thing? The curvilinear effect of intelligence on perceived leadership behavior. Journal of Applied Psychology, 102(7), 1003–1021. [Optimal leader IQ ≈ 1.2 SD above group]

Biomarkers, Pupil Size & Neural Signatures

Tsukahara, J.S., Harrison, T.L., & Engle, R.W. (2016). The relationship between baseline pupil size and intelligence. Cognitive Psychology, 91, 109–123. [r≈.30-.39 extreme groups; locus coeruleus hypothesis]

Tsukahara, J.S., & Engle, R.W. (2021). Is baseline pupil size related to cognitive ability? Yes (under proper lighting conditions). Cognition, 211, 104643.

Unsworth, N., Miller, A.L., & Robison, M.K. (2023). Baseline pupil diameter does not correlate with fluid intelligence. Psychonomic Bulletin & Review. [Replication failure; methodological debate]

Kokkinakis, A.V., et al. (2017). Exploring the relationship between video game expertise and fluid intelligence. PLOS ONE, 12(11), e0186621. [MOBA skill ↔ Gf, r≈.30-.40]

Stansfeld, S.A., et al. (2005). Aircraft and road traffic noise and children's cognition and health. Lancet, 365(9475), 1942–1949. [Chronic noise → lower reading/IQ]

Childhood, Academic, Sports & Occupational

Flensborg-Madsen, T., & Mortensen, E.L. (2018). Associations of early developmental milestones with adult intelligence. Child Development, 89(2), 638–648. [N=821; language milestones β=−.17; 20% variance at 24m]

Deary, I.J., Strand, S., Smith, P., & Fernandes, C. (2007). Intelligence and educational achievement. Intelligence, 35(1), 13–21. [N=70,000; r=.81 IQ ↔ GCSE scores at 16]

Lubinski, D., & Benbow, C.P. (2006). Study of Mathematically Precocious Youth after 35 years. Perspectives on Psychological Science, 1(4), 316–345. [Top 0.01%: 50% doctorates; linear benefit within gifted]

Coyle, T.R., & Pillow, D.R. (2008). SAT and ACT predict college GPA after removing g. Intelligence, 36(6), 719–729.

Burgoyne, A.P., et al. (2016). The relationship between cognitive ability and chess skill: A comprehensive meta-analysis. Intelligence, 59, 72–83. [Overall r≈.24; strongest with Gf; weaker in experts]

Kokkinakis, A.V., et al. (2017). Exploring the relationship between video game expertise and fluid intelligence. PLOS ONE, 12(11), e0186621. [MOBA rank ↔ Gf]

Kirkegaard, E.O.W. (2019). Is national mental sport ability a sign of intelligence? Mankind Quarterly, 59(3). [12 games; r=.79 national IQ ↔ top player representation]

Hauser, R.M. (2002). Meritocracy, cognitive ability, and the sources of occupational success. CDE Working Paper No. 98-07 (revised).

Wai, J., & Kanaya, T. (2024). Meta-analysis: On average, undergraduate students' intelligence is merely average. ScienceOpen Preprints. [Average undergrad IQ ≈ 102; −0.2 pts/year decline]

Ruf, D. (2005). Losing Our Minds: Gifted Children Left Behind. Great Potential Press. [Five levels of giftedness; milestone timetables]

Fertility, Assortative Mating & Humor

Retherford, R.D., & Sewell, W.H. (1988). Intelligence and family size reconsidered. Social Biology, 35(1-2), 1–40. [N=9,000; decline of .81 IQ pts/generation; .57 after heritability correction]

Lynn, R., & Van Court, M. (2004). New evidence of dysgenic fertility for intelligence in the United States. Intelligence, 32(2), 193–201. [Consistently negative 1900–1979 cohorts; .90 pts/gen]

Kanazawa, S. (2014). Intelligence and childlessness. Social Science Research, 48, 157–170. [+15 IQ pts → 21–25% lower odds of parenthood in women]

Lynn, R. (2011). Dysgenics: Genetic Deterioration in Modern Populations. 2nd ed. Ulster Institute for Social Research.

Kong, A., et al. (2017). Selection against variants in the genome associated with educational attainment. PNAS, 114(5), E727–E732. [Polygenic scores for g declining across generations in Iceland]

Mascie-Taylor, C.G.N. (1989). Spouse similarity for IQ and personality and convergence. Behavior Genetics, 19(2), 223–227. [r≈.40–.45 spousal IQ; no convergence; initial assortment only]

Jensen, A.R. (1998). The g Factor: The Science of Mental Ability. Praeger. [Spousal IQ r≈.45 across 43 studies; 15–20% variance from assortative mating]

Gignac, G.E., et al. (2019). People tend to overestimate their romantic partner's intelligence even more than their own. Intelligence, 73, 41–51. [218 couples; +30 pts self, +36–38 pts partner]

Greengross, G., & Miller, G. (2011). Humor ability reveals intelligence, predicts mating success, and is higher in males. Intelligence, 39(4), 188–192. [Comedians > students on verbal IQ and humor production]

Holt, D. (1995). The relationship between humor and giftedness. [Gifted students: more incongruity-based and wordplay jokes]

Gino, F., & Galinsky, A. (2015). Sarcasm, creativity, and the brain. Harvard Business School Working Paper. [Sarcasm requires overcoming literal/intended contradiction → activates creative thinking]

Happiness, Creativity, Income & Wealth

Ali, A., et al. (2013). The relationship between happiness and intelligent quotient: The contribution of socio-economic and clinical factors. Psychological Medicine, 43(6), 1303–1312. [N=6,870; IQ 70–99 lowest happiness; mediators reduce link 50%]

Li, N.P., & Kanazawa, S. (2016). Country roads, take me home… to my friends: How intelligence, population density, and friendship affect modern happiness. British Journal of Psychology, 107(4), 675–697. [High IQ + socializing = lower satisfaction]

Nikolaev, B., & McGee, J.J. (2016). Relative verbal intelligence and happiness. Intelligence, 59, 1–7. [National IQ ↔ happiness inequality r=−.50]

Zagorsky, J.L. (2007). Do you have to be smart to be rich? The impact of IQ on wealth, income and financial distress. Intelligence, 35(5), 489–501. [N=7,403; IQ→income r≈.30; IQ→wealth ≈0; $234–616/IQ pt/yr]

Hauck, W., & Thomas, J. (1972). The relationship of humor to intelligence, creativity, and intentional and incidental learning. Journal of Experimental Education, 40(4), 52–55. [Children: humor-IQ r=.91; humor-creativity r=.89]

Benedek, M., et al. (2021). The relationship between intelligence and divergent thinking — a meta-analytic update. Journal of Intelligence, 9(2), 23. [849 effects, N=34,610; r=.25 overall; DT originality r≈.31-.37]

Kałowski, P., et al. (2023). Irony use and cognitive correlates. [Irony ↔ creativity, cognitive flexibility, nonverbal IQ, mindfulness]

Robson, D. (2015). The surprising downsides of being clever. BBC Future. [Summary of Terman's longitudinal findings on gifted unhappiness]

Raghunathari, R. (2016). If You're So Smart, Why Aren't You Happy? Portfolio/Penguin. [Autonomy, mastery, relationships as happiness mediators]

Temporal Discounting, Impostor Syndrome & Morality

Sanchez-Roige, S., et al. (2018). Genome-wide association study of delay discounting in 23,217 adult research participants identifies an association with NCAM1. Nature Neuroscience, 21(1), 16–18. [Genetic overlap: discounting ↔ childhood IQ rg=−.63; ↔ education rg=−.67]

Keidel, K., et al. (2021). Individual differences in intertemporal choice. Frontiers in Psychology, 12, 643670. [Comprehensive review; IQ-discounting effect exceeds personality effects]

Shoda, Y., Mischel, W., & Peake, P.K. (1990). Predicting adolescent cognitive and self-regulatory competencies from preschool delay of gratification. Developmental Psychology, 26(6), 978–986. [Original marshmallow test follow-up]

Clance, P.R., & Imes, S.A. (1978). The impostor phenomenon in high-achieving women: Dynamics and therapeutic intervention. Psychotherapy: Theory, Research & Practice, 15(3), 241–247.

Bravata, D.M., et al. (2020). Prevalence, predictors, and treatment of impostor syndrome: A systematic review. Journal of General Internal Medicine, 35(4), 1252–1275.

Furnham, A. (2001). Self-estimates of intelligence: Culture and gender difference. Personality and Individual Differences, 31(8), 1381–1405. [Men overestimate, women underestimate own IQ]

Kruger, J., & Dunning, D. (1999). Unskilled and unaware of it. Journal of Personality and Social Psychology, 77(6), 1121–1134. [Dunning-Kruger effect]

College Majors, Lucid Dreaming & Metacognition

Educational Testing Service (ETS). GRE scores by intended graduate major field (2017–2020). [Physics & Astronomy highest composite; Education ~1 SD below on both verbal and quantitative]

College Board (2021). SAT scores of college-bound seniors by intended major. [Mathematics/Statistics SAT Total 117.9 IQ equivalent vs Education 101.6]

Frey, M.C., & Detterman, D.K. (2004). Scholastic assessment or g? The relationship between the SAT and general cognitive ability. Psychological Science, 15(6), 373–378. [SAT ↔ g correlation r≈.82]

Olson, R. (2014). Average IQ of students by college major and gender ratio. [Quantitative SAT drives apparent IQ ranking; R²=.74 with gender ratio]

Filevich, E., Dresler, M., Brick, T.R., & Kühn, S. (2015). Metacognitive mechanisms underlying lucid dreaming. Journal of Neuroscience, 35(3), 1082–1088. [Larger aPFC in lucid dreamers; higher metacognitive activation]

Bourke, P., & Shaw, H. (2014). Spontaneous lucid dreaming frequency and waking insight. Dreaming, 24(2), 152–159. [Lucid dreamers solve 25% more insight puzzles]

Lubinski, D., & Benbow, C.P. (2006). Study of Mathematically Precocious Youth. [High V+Q scorers disproportionately enter physics]

University Majors, EI/ToM & German Research

ETS (2020). GRE Scores by Intended Graduate Major. Educational Testing Service. [Physics/Astronomy top both Verbal & Quantitative]

College Board (2021). SAT Suite of Assessments Annual Report. [Math/Stats ~118 IQ vs Education ~102 IQ; ~16pt gap]

Olson, R. (2014). Average IQ of students by college major and gender ratio. [Quantitative SAT drives hierarchy R²=.74]

Schulte, M.J., et al. (2004). Emotional intelligence: Not much more than g and personality. Personality and Individual Differences, 37(5), 1059–1068. [EI ↔ g r=.45]

Baker, C.A., et al. (2014). Reading the Mind in the Eyes: A meta-analysis. [RMET ↔ IQ r=.24]

Nguyen, N.N., et al. (2020). A meta-analytic investigation of the relationship between EI and emotional manipulation. SAGE Open.

Heil, C. (2021). Hochbegabte Erwachsene [Gifted Adults]. Psychotherapie Heil. [N=87; IQ 130–144; fast thinking r=.24; logical ability r=.31; 88.9% no school support]

Rost, D.H. (2000). Hochbegabte und hochleistende Jugendliche. Waxmann. [Marburger Hochbegabtenprojekt; g as central variable]

Heller, K.A. (2001). Münchner Hochbegabtenuntersuchung. [Munich Model of Giftedness; multidimensional]

Gross, M.U.M. (2006). Exceptionally gifted children: Long-term outcomes of academic acceleration and nonacceleration. Journal for the Education of the Gifted, 29(4), 404–429. [IQ >160; acceleration → higher life satisfaction]

Metzen, D., Genç, E., et al. (2023). Structural architecture and brain network efficiency links polygenic scores to intelligence. Human Brain Mapping. [Ruhr-Universität Bochum; genes → brain networks → IQ pathway]

University Majors, g-Factor & Job Validity

ETS (2020). GRE scores by intended graduate major field. Educational Testing Service. [Physics/Astronomy top composite; Education ~1 SD below Math/Stats]

College Board (2021). SAT scores by intended college major. [Nationally representative sample SAT Total = 1010]

Wai, J., & Kanaya, T. (2024). Meta-analysis: On average, undergraduate students’ intelligence is merely average. ScienceOpen Preprints.

Frey, M.C., & Detterman, D.K. (2004). Scholastic assessment or g? The relationship between the Scholastic Assessment Test and general cognitive ability. Psychological Science, 15(6), 373–378. [SAT ↔ g r≈.82]

Breit, M., et al. (2024). The stability of cognitive abilities: A meta-analytic review of longitudinal studies. Psychological Bulletin, 150(4), 399–439. [r=.67 over 59 years; r=.54 over 79 years]

Sackett, P.R., et al. (2022). Revisiting meta-analytic estimates of validity in personnel selection. Journal of Applied Psychology, 107(11), 2040–2068. [Revised GMA→job to ρ=.31]

Sackett, P.R., et al. (2024). [New meta-analysis ρ=.22]

Berry, C.M., et al. (2024). Insights from an updated personnel selection meta-analytic matrix. Journal of Applied Psychology. [Excluding GMA: little validity loss, large adverse impact reduction]

Hambrick, D.Z., et al. (2024). The validity of general cognitive ability predicting job-specific performance is stable across different levels of job experience. Journal of Applied Psychology, 109(3), 437–455.

Sjöberg, A., & Sjöberg, S. (2025). General cognitive ability and job performance in personnel selection in Sweden: A meta-analysis. [observed r=.19, corrected ρ=.32]

Stanek, K.C., & Ones, D.S. (2023). Meta-analytic relations between personality and cognitive ability. PNAS, 120(23), e2212794120. [60,690 relations; 3,543 meta-analyses; millions of participants]

Romance, Economics, Policy & Cross-Cultural

Horwitz, T.B., et al. (2023). Evidence of correlations between human partners based on systematic reviews and meta-analyses of 22 traits. Nature Human Behaviour, 7, 1169–1183. [~23,000 pairs; cognitive ability among strongest assortment variables]

Zietsch, B.P., et al. (2011). Variation in human mate choice: Simultaneously investigating heritability, parental influence, sexual imprinting, and assortative mating. American Naturalist, 177(5), 605–616. [N>20,000; near-zero genetic influence on mate choice itself]

Todd, P.M., et al. (2007). Different cognitive processes underlie human mate choices and mate preferences. PNAS, 104(38), 15011–15016. [Speed-dating: stated preferences ≠ actual choices]

Gignac, G.E., et al. (2019). People tend to overestimate their romantic partner’s intelligence. Intelligence, 73, 41–51. [218 couples; +36–38 pts partner overestimation]

Lynn, R., & Vanhanen, T. (2002). IQ and the Wealth of Nations. Praeger. [National IQ ↔ GDP r≈.70; contested methodology]

Jones, G., & Schneider, W.J. (2006). Intelligence, human capital, and economic growth: A Bayesian averaging of classical estimates approach. Journal of Economic Growth, 11(1), 71–93. [IQ = “best predictor” across 67+ variables]

Heckman, J.J. (2006). Skill formation and the economics of investing in disadvantaged children. Science, 312(5782), 1900–1902. [Non-cognitive skills compensate for lower IQ; Nobel laureate]

Poropat, A.E. (2009). A meta-analysis of the five-factor model of personality and academic performance. Psychological Bulletin, 135(2), 322–338. [Conscientiousness ↔ GPA nearly = IQ ↔ GPA]

Neubauer, A.C., & Knorr, E. (1998). Three paper-and-pencil tests for speed of information processing. Personality and Individual Differences, 25(3), 521–531. [Reaction time ↔ IQ r≈−.30 to −.40]

Spitzer, M. (2018). Zur Erforschung menschlicher Intelligenz. Nervenheilkunde, 37(9), 617–633. [Norwegian Flynn reversal; school reform +1–5 IQ pts; German-language review]

Kokkinakis, A.V., et al. (2017). Exploring the relationship between video game expertise and fluid intelligence. PLOS ONE, 12(11), e0186621. [MOBA rank ↔ Gf]

Policy Views, Drink/Food, Social Dynamics, EI, Novel Findings

Erceg, N., Greenberg, S., & Cobeta, B. (2024). What’s really true about intelligence and IQ? We empirically tested 40 claims. ClearerThinking.org. [N=3,691; 62 tasks; 40 claims tested]

PNAS Nexus (2023). Cognitive ability and ideology join forces in the culture war: A model of opinion formation. [Argument advantage model]

Onraet, E., et al. (2015). The association of cognitive ability with right-wing ideological attitudes and prejudice: A meta-analytic review. European Journal of Personality, 29, 599–621. [67 studies, N>84K]

Edwards, T., et al. (2024). Predicting political beliefs with polygenic scores for cognitive performance and educational attainment. Intelligence. [Within-family design; polygenic scores → social liberalism]

Mortensen, E.L., et al. (2005). Intelligence in relation to later beverage preference and alcohol intake. Addiction, 100(10), 1445–1452. [Danish cohort N=1,800; wine preference OR=2.8]

Rick, S., & Schweitzer, M. (2012). The imbibing idiot bias. Journal of Consumer Psychology, 23(2), 212–219. [Holding alcohol → perceived as less intelligent]

Li, N.P., & Kanazawa, S. (2016). Country roads, take me home… to my friends: How intelligence, population density, and friendship affect modern happiness. British Journal of Psychology, 107(4), 675–697.

Taleb, N.N. (2019/2025). IQ is largely a pseudoscientific swindle. Medium/INCERTO. [Fat tails argument; R² critique]

Richardson, K. (2015). Does IQ really predict job performance? PMC. [Critique of range restriction corrections and supervisor ratings]

Dunedin Study & Longitudinal Sources

Schaefer, J.D., et al. (2016). Early-life intelligence predicts midlife biological age. Journal of Gerontology B, 71(6), 968–977.

Elliott, M.L., et al. (2021). Brain-age in midlife is associated with accelerated biological aging and cognitive decline. Molecular Psychiatry, 26, 3829–3838.

Moffitt, T.E., et al. (2011). A gradient of childhood self-control predicts health, wealth, and public safety. PNAS, 108(7), 2693–2698.

Richmond-Rakerd, L.S., et al. (2021). Childhood self-control forecasts the pace of midlife aging. PNAS, 118(3), e2010211118.

Reuben, A., et al. (2017). Association of childhood blood lead levels with cognitive function and socioeconomic status at age 38. JAMA, 317(12), 1244–1251.

Caspi, A., et al. (2016). Childhood forecasting of a small segment of the population with large economic burden. Nature Human Behaviour, 1, 0005.

Harvard Grant Study, Rob Henderson

Vaillant, G.E. (1977). Adaptation to Life. Harvard University Press. [Grant Study: defense mechanisms > IQ for life outcomes]

Vaillant, G.E. (2002). Aging Well. Little, Brown. [Education predicts healthy aging beyond IQ and SES]

Waldinger, R.J., & Schulz, M.S. (2023). The Good Life: Lessons from the World’s Longest Scientific Study of Happiness. Simon & Schuster. [Warm relationships > IQ for health at 80]

Henderson, R. (2023). Nobody is a prisoner of their IQ. Rob Henderson’s Newsletter. [Social norms compensate for lower IQ; luxury beliefs concept]

Note on citation completeness (v4): This atlas now spans 55 substantive sections (including translated German research from Heil 2021, Rost, Heller, and Metzen/Genç 2023) plus references. r-values and effect sizes are rounded approximations. Contested and preliminary findings are tagged throughout. The fertility/dysgenics section (§35) contains findings that are politically controversial but empirically well-documented. The Zagorsky income/wealth paradox (§40) is one of the most counter-intuitive findings in the literature: IQ predicts income but not wealth. The happiness section (§38) reveals that Terman's gifted cohort (mean IQ 150) was not significantly happier than average over 35 years of follow-up. The creativity meta-analysis (§39, N=34,610) finds r=.25 overall with DT originality scores reaching r≈.37 — and sarcasm exposure tripling creative task performance in experimental settings. The atlas draws from over 25 major longitudinal datasets across 15+ countries. Bar widths remain illustrative approximations. Some entries (voice pitch, exotic pets, motion sickness) are speculative inclusions flagged accordingly.
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