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Biological determinism

Biological determinism is the theory that biological factors, particularly genetic inheritance, are the principal causes of differences in human physical traits, cognitive abilities, behaviors, and social outcomes, often minimizing the role of environmental influences.^[1] This perspective gained prominence in the late 19th century through figures like Francis Galton, a British polymath who, inspired by Charles Darwin's theory of natural selection, pioneered statistical methods to quantify the heritability of human qualities such as intelligence and emphasized the transmission of superior traits across generations.^[2] Empirical support for biological determinism derives substantially from behavioral genetics research, including twin studies that estimate the heritability of intelligence at 50-80% in adulthood and similar genetic influences on personality traits, indicating that genetic variation accounts for a major portion of phenotypic variance even when controlling for shared environments.^[3] Adoption studies further reinforce this by showing greater similarity between biological relatives than adoptive ones for these traits.^[3] Controversies surrounding biological determinism often arise from its implications for group differences—such as in sex, race, or class—and historical associations with eugenics, yet critiques frequently overlook accumulating genomic evidence from genome-wide association studies (GWAS) that identify specific genetic variants linked to complex behaviors, challenging strict environmentalist accounts.^[4] While not implying absolute predestination—gene-environment interactions exist—the doctrine prioritizes causal realism by recognizing biology's foundational role in human variation, countering blank-slate ideologies that have dominated much of 20th-century social science despite contrary data.^[3]^[4]

Definition and Core Principles

Conceptual Foundations

Biological determinism posits that biological factors, chiefly genetic inheritance, are the primary determinants of an organism's traits, behaviors, and capacities, exerting causal primacy over environmental influences. This view emphasizes fixed hereditary endowments transmitted at conception as shaping phenotypic outcomes, often through mechanisms like germline continuity that preclude significant modification by experience.^[1]^[5] The concept underscores a reductionist approach, wherein complex characteristics reduce to underlying biological substrates rather than emergent interactions.^[6] A foundational element is the isolation of hereditary material from somatic alterations, as theorized by August Weismann in The Germ-Plasm (1892). Weismann contended that germ plasm—the continuous lineage of hereditary determinants—confines itself to reproductive cells, forming an impermeable barrier against bodily changes, thus ensuring traits pass unaltered except through germline variation. This refuted Lamarckian inheritance of acquired traits, establishing heredity as a deterministic vector immune to individual life's contingencies.^[7]^[8] Francis Galton advanced the framework empirically in Hereditary Genius (1869), using pedigree analyses of 977 eminent figures to quantify familial resemblances in ability, estimating that intellectual eminence arises predominantly from inherited "natural ability" rather than nurture alone. Galton's biometrical methods, including the law of ancestral heredity, modeled trait transmission as probabilistic blends from forebears, quantifying biology's overriding influence via coefficients of correlation.^[9]^[10] These innovations shifted conceptual emphasis from anecdotal to statistical evidence, portraying human variation as biologically anchored.^[11] Philosophically, biological determinism aligns with causal mechanisms rooted in material substrates, prioritizing innate dispositions over volitional or cultural malleability in foundational trait formation. Early articulations, while probabilistic in Galton's statistics, rejected environmental determinism by demonstrating heritability's empirical weight in twin-like resemblances and regression patterns.^[9] This laid groundwork for viewing social phenomena, from capability to conduct, as extensions of biological imperatives.^[1]

Key Distinctions and Misconceptions

Biological determinism emphasizes the causal primacy of innate biological mechanisms, including genetics, physiology, and neural structures, in shaping traits and behaviors, but it is often misconstrued as excluding any environmental role. In reality, this view posits biology as setting constraints and predispositions that environment modulates rather than overrides, distinguishing it from pure environmentalism which attributes outcomes chiefly to external factors. A frequent misconception frames biological determinism as rigid fatalism, ignoring evidence from gene-environment interactions (G×E) where contexts like social rearing alter gene expression and phenotypic outcomes, as seen in animal models of aggression and brain wiring.^[12] High heritability estimates from twin and adoption studies—typically 40–80% for cognitive and personality traits—do not imply individual-level predestination or immunity to environmental change, contrary to another common misconception. Heritability quantifies the proportion of population variance attributable to genetic differences under specific conditions, not the absolute fixity of traits or the futility of interventions; for instance, nutritional improvements have raised average heights despite heritability exceeding 80% in well-nourished populations.^[3] This distinction underscores that while genetics explain much within-group variation, cross-population shifts via environment remain possible, though limited by biological ceilings. Biological determinism is further distinguished from outdated reductionism by incorporating probabilistic causation, where genes increase likelihoods rather than guarantee outcomes, yet critics often erect a straw-man dichotomy pitting "nature" against "nurture." Evolutionary and behavioral genetic frameworks explicitly reject both extremes, advocating dynamic interplay, as evidenced by analyses showing textbook misrepresentations attribute wholesale determinism to these fields despite their interactionist foundations.^[13] Such errors stem partly from ideological resistance to biological causality, overlooking empirical data from molecular studies affirming biology's foundational yet flexible role.^[12]

Scientific Evidence for Biological Influences

Heritability from Classical Studies

Classical studies in behavioral genetics, primarily through twin, family, and adoption designs, have provided foundational estimates of trait heritability by partitioning variance into genetic and environmental components. Monozygotic twins, sharing nearly 100% of their genes, typically show higher trait correlations than dizygotic twins, who share about 50%, allowing heritability (h²) to be estimated as roughly twice the difference in their correlations (2(r_MZ - r_DZ)) under assumptions of equal environments.^[3] Adoption studies further disentangle effects by comparing biological relatives separated from adoptive ones, isolating genetic influences from shared rearing environments.^[14] For intelligence, measured via IQ or general cognitive ability (g), twin studies consistently yield heritability estimates ranging from 50% to 80% in adults, with meta-analyses confirming an increase across development from around 20-40% in childhood to over 60% in adulthood due to gene-environment amplification.^[3] ^[15] Early adoption studies, such as those in the Colorado and Texas Adoption Projects, support these figures, showing adopted children's IQs correlating more strongly with biological parents (genetic transmission) than adoptive ones, with negligible shared environmental effects in adulthood (c² ≈ 0%).^[16] ^[17] Personality traits exhibit moderate heritability of 20% to 50% from twin and family studies, with genetic factors influencing dimensions like extraversion, neuroticism, and conscientiousness via the Big Five model.^[3] ^[18] These estimates hold across diverse populations, though shared environment plays a larger role in childhood, diminishing over time as nonshared environmental influences dominate variance.^[19]

Trait	Heritability Range	Study Type	Key Reference
General Intelligence	50-80%	Twin studies (adults)	^[3]
IQ	55%+ (increasing)	Longitudinal twin/adoption meta-analysis	^[15]
Personality Traits	20-50%	Twin/family studies	^[18]

Critics note potential biases like assortative mating or twin-specific environments inflating estimates, yet robustness across designs and convergence with molecular findings affirm substantial genetic causation for individual differences.^[20] These classical approaches underscore biological determinism's empirical basis, revealing genetics as a primary driver of trait variance beyond environmental confounds.^[21]

Molecular and Genomic Evidence

Molecular and genomic techniques, including genome-wide association studies (GWAS) and polygenic scoring, have identified thousands of genetic variants associated with complex human traits, providing direct evidence of biological influences on phenotypic variation. These methods scan the genome for single nucleotide polymorphisms (SNPs) that correlate with traits, revealing polygenic architectures where many loci of small effect contribute to heritability. For instance, GWAS on height—a benchmark polygenic trait—have explained up to 40-50% of twin-study heritability through aggregated SNP effects, demonstrating the feasibility of capturing genetic contributions at the molecular level.^[22] In cognitive abilities, large-scale GWAS have pinpointed loci linked to intelligence, with polygenic scores derived from these studies predicting 4-10% of variance in IQ and educational attainment as of 2018, a figure that has improved with larger cohorts exceeding 1 million participants. A 2023 analysis showed these scores more strongly predict crystallized intelligence (knowledge-based) than fluid intelligence (novel problem-solving), underscoring domain-specific genetic influences. Recent 2025 GWAS further confirm associations between specific gene loci and general cognitive ability (g-factor), aligning with twin heritability estimates of 50-80% while highlighting the polygenic nature of intelligence.^[23]^[24]^[25] For behavioral traits like personality, molecular evidence supports substantial genetic components, with GWAS identifying hundreds of variants influencing the Big Five dimensions (e.g., extraversion, neuroticism), consistent with twin-based heritability of 30-60%. SNP-based heritability estimates, though initially lower than twin studies for behaviors (e.g., 10-20% vs. 40-60%), indicate pervasive genetic signals, with gaps attributed to rare variants, gene-environment interactions, or non-additive effects rather than absence of biological causation. Childhood behavioral problems exhibit ~40% heritability corroborated by genomic data, reinforcing causal genetic roles in developmental trajectories.^[26]^[27]^[28] These findings counter simplistic environmental determinism by demonstrating that genomic variation causally contributes to trait differences, as validated through methods like Mendelian randomization, which leverage genetic variants as instrumental variables to infer directionality. While full mechanistic pathways remain under study, the accumulation of replicable loci across traits affirms biological determinism's core tenet: DNA sequence variations drive predictable differences in organismal outcomes, independent of cultural or experiential confounds.^[22]

Recent Empirical Developments (2000–2025)

The advent of genome-wide association studies (GWAS) following the Human Genome Project's completion in 2003 marked a pivotal shift, enabling the identification of specific genetic variants influencing complex behavioral traits and corroborating high heritability estimates from earlier twin and adoption studies.^[23] Large-scale GWAS, leveraging cohorts like the UK Biobank established in 2006, have pinpointed thousands of single-nucleotide polymorphisms (SNPs) associated with traits such as intelligence, where polygenic scores (PGS) derived from these variants now explain up to 10-12% of variance in cognitive performance, rising from under 2% in early 2010s analyses.^[29]^[24] For instance, a 2017 GWAS on extreme intelligence identified loci accounting for 1.6% of normal-range variance, with subsequent meta-analyses in 2023-2024 validating PGS predictive power across diverse samples, including within-family designs that control for environmental confounds.^[29]^[30]^[31] Twin studies conducted post-2000, incorporating millions of pairs via national registries, have refined heritability estimates for intelligence to 50% in childhood, increasing to 70-80% in adulthood, reflecting genetic influences strengthening over time as individuals select environments aligned with predispositions.^[32]^[33] Similar patterns hold for personality traits, where 2024 Yale-led research linked novel genetic variants to Big Five dimensions like extraversion and neuroticism, with PGS explaining 5-10% of variance, consistent with twin-derived heritabilities of 40-60%.^[34] Behavioral genetics syntheses emphasize that nearly all human traits show substantial genetic contributions, with shared environment effects minimal beyond infancy, as evidenced by discordant monozygotic twins.^[35]^[36] Developments in polygenic scoring have extended to psychiatric and behavioral outcomes, such as schizophrenia and educational attainment (a proxy for cognitive ability), where 2020-2025 GWAS meta-analyses yield PGS predicting 10-20% of liability variance, outperforming single-gene models and underscoring polygenic determinism over rare variants alone.^[37]^[22] Integration of GWAS with functional genomics, including 2021-2025 brain imaging studies, reveals these variants cluster in neural development pathways, providing causal mechanistic insights absent in classical designs.^[38] Despite sample size expansions to over a million genomes by 2025, PGS out-of-sample prediction remains below twin-study heritabilities, attributed to "missing heritability" from rare variants and gene-environment correlations, yet affirming biology's dominant role in trait variation.^[30]^[39] These findings counter earlier nurture-dominant narratives by demonstrating scalable genetic prediction from birth, independent of socioeconomic status in within-family analyses.^[31]

Historical Development

Early Biological Theories

In ancient Greece, Hippocrates (c. 460–370 BCE) articulated an early theory of heredity suggesting that "seeds" for reproduction are drawn from all parts of the parents' bodies and collected in the reproductive organs, thereby transmitting physical and potentially temperamental traits innately through biological material rather than solely environmental factors.^[40] This pangenesis-like mechanism implied a deterministic role for parental biology in offspring characteristics, as the seeds carried particulate contributions from bodily organs.^[41] Aristotle (384–322 BCE) refined these ideas, proposing that heredity occurs via a blending inheritance where male and female contributions mix like liquids, with blood supplying the generative essence that fixes traits at conception through biological potentiality actualized in development.^[40] His framework emphasized innate biological causation over external molding, viewing deviations as resemblances to parental forms determined by the proportional mixture of essences.^[41] Roman physician Galen (129–c. 216 CE) extended this deterministic tradition with a two-seed theory, positing that both parents produce semen containing corpuscular particles derived from their organs and humors, which combine to predetermine the offspring's morphology, faculties, and disease propensities biologically.^[42] Unlike Aristotle's emphasis on male dominance, Galen's model granted females an active generative role, yet maintained that traits emerge from the innate organization of these biological seeds, with environmental influences secondary to the initial corporeal contributions.^[43] Medieval scholars, building on Galen, integrated these concepts into humoral physiology, where innate imbalances in bodily fluids—transmitted hereditarily—were seen as biologically fixing temperaments and predispositions from birth.^[44] By the 17th century, preformationism emerged as a starkly deterministic doctrine, asserting that embryos exist as fully formed miniature adults (homunculi) pre-packaged within gametes—either in eggs (ovism) or sperm (animalculism)—unfolding mechanistically without novel structures arising during development.^[45] Microscopists such as Antonie van Leeuwenhoek (1632–1723) and Jan Swammerdam (1637–1680) claimed empirical support from observations of apparent tiny organisms in semen, reinforcing the view that all traits, including complex forms, are biologically predetermined at fertilization by divine or natural pre-arrangement.^[40] This theory, contrasting with epigenesis, minimized environmental plasticity, portraying development as an inexorable unfolding of innate biological programming, though later challenged by evidence of gradual formation.^[46] These pre-modern frameworks collectively prioritized biological inheritance as the primary causal agent for traits, setting conceptual precedents for later hereditarian doctrines despite their speculative foundations lacking modern empirical validation.^[47]

19th–Early 20th Century Applications

In the late 19th century, Francis Galton, a British scientist and cousin of Charles Darwin, formalized eugenics as a practical application of biological determinism, coining the term in his 1883 book Inquiries into Human Faculty and Its Development. Galton argued that human qualities such as intelligence and moral character were largely inherited, proposing selective breeding to enhance desirable traits by encouraging reproduction among the "fit" and restricting it among the "unfit." This positive and negative eugenics framework drew on statistical analyses of family pedigrees and twin resemblances, positing that societal progress depended on improving the genetic stock rather than solely environmental reforms.^[48]^[49] Parallel developments included Herbert Spencer's Social Darwinism, which extended evolutionary principles to human societies starting in his 1851 work Social Statics. Spencer applied the concept of "survival of the fittest"—a phrase he coined—to justify social hierarchies, asserting that biological fitness determined economic and class outcomes, with the least adapted individuals naturally eliminated through competition. This view supported laissez-faire policies, viewing poverty and inequality as evidence of inherent inferiority rather than remediable social conditions.^[50]^[51] In criminology, Cesare Lombroso advanced biological determinism through his 1876 theory of the "born criminal," detailed in L'Uomo Delinquente. Examining autopsy data from over 400 Italian criminals, Lombroso identified physical stigmata—such as asymmetrical skulls, large jaws, and low foreheads—as atavistic throwbacks to primitive ancestors, claiming these traits predisposed individuals to crime independently of environment. His Italian School of Positivist Criminology influenced early forensic practices and policies favoring segregation or sterilization of those exhibiting such features, though later critiques highlighted methodological flaws like selection bias.^[52]^[53] Early 20th-century applications intensified with intelligence testing, as H.H. Goddard translated the Binet-Simon scale in 1908 and applied it to U.S. immigrants at Ellis Island, concluding that 83% of Jews, Hungarians, and Italians were feebleminded due to innate defects. Lewis Terman refined this into the 1916 Stanford-Binet test, establishing IQ as a fixed, hereditary metric that stratified society into ability classes, informing eugenic recommendations against reproduction by low-IQ groups. World War I Army Alpha and Beta tests on 1.7 million recruits reinforced these claims, with data interpreted as showing hereditary intellectual inferiority among certain ethnic groups, contributing to the 1924 U.S. Immigration Act's quotas limiting "undesirable" nationalities. In the U.S., eugenics policies culminated in Indiana's 1907 sterilization law for the "unfit," expanding to 30 states by 1930, affecting over 60,000 individuals presumed biologically inferior.^[54]^[55]^[56]

Mid-20th Century to Sociobiology

In the aftermath of World War II, biological determinism was largely discredited due to its links with eugenics and Nazi racial policies, prompting a shift toward environmental explanations for human behavior in academic and policy circles.^[57] Despite this, advances in genetics continued, with the 1953 elucidation of DNA's double helix structure by James Watson and Francis Crick providing a molecular basis for inheritance that underpinned later behavioral research.^[58] Quantitative methods in behavioral genetics, including twin and adoption studies, gained traction in the 1950s and 1960s, estimating heritability for psychological traits like intelligence at 50-80% based on comparisons of monozygotic and dizygotic twins reared apart or together.^[59] A pivotal moment came in 1969 when psychologist Arthur R. Jensen published "How Much Can We Boost IQ and Scholastic Achievement?" in the Harvard Educational Review, analyzing data from over 1,000 studies to conclude that IQ heritability within populations exceeds 0.80 and that compensatory education programs had minimal long-term effects on cognitive abilities, suggesting genetic influences on group differences in IQ scores.^[60]^[61] Jensen's hereditarian stance provoked backlash, including accusations of racism, but his estimates aligned with independent twin studies showing IQ correlations of 0.86 for identical twins versus 0.60 for fraternal twins.^[62] The controversy highlighted tensions between empirical data and egalitarian ideologies prevalent in mid-century social sciences, where environmentalism dominated despite contrary evidence from controlled designs.^[57] The founding of the Behavior Genetics Association in 1970 formalized the field, fostering research into genetic variances in personality and psychopathology using advanced statistical models like analysis of variance.^[59] This period saw behavioral genetics transition from animal models—such as Seymour Benzer's 1950s Drosophila studies linking genes to learning—to human applications, challenging blank-slate views with data indicating genetic factors explain 40-60% of variance in traits like extraversion.^[58]^[63] Sociobiology emerged as a synthesis in 1975 with E.O. Wilson's Sociobiology: The New Synthesis, which applied evolutionary theory and population genetics to social behaviors across species, emphasizing ultimate causation via natural selection over proximate mechanisms.^[64] Wilson argued that traits like altruism evolve through kin selection, as formalized by W.D. Hamilton's 1964 rule (rB > C, where r is relatedness, B benefit to recipient, and C cost to actor), supported by observations in hymenopteran insects where sterile workers aid relatives.^[64] The book's 27th chapter on humans proposed that evolutionary pressures shaped social structures, including mating systems and aggression, drawing on ethological data rather than direct genetic mapping.^[65] Wilson's framework faced immediate opposition from the Sociobiology Study Group, led by left-leaning academics like Stephen Jay Gould, who critiqued it as genetic determinism reinforcing social hierarchies, though such charges often conflated descriptive evolutionary analysis with prescriptive ideology.^[66] Empirical validations, including later genomic studies confirming selection on social genes, have substantiated core sociobiological claims, revealing biases in institutional critiques that prioritized cultural relativism over causal evidence from comparative biology.^[64]^[57]

Applications to Specific Traits

Intelligence and Cognitive Abilities

Twin and adoption studies consistently demonstrate high heritability for intelligence, as measured by IQ and related cognitive tests, with estimates ranging from 50% to 80% of variance attributable to genetic factors in adulthood within populations of Western European descent.^[67] A comprehensive meta-analysis of over 2,700 twin studies encompassing 14 million twin pairs reported a broad-sense heritability of approximately 0.50 for cognitive abilities, though narrower estimates excluding shared environment often exceed 0.70 for adult IQ.^[67] These figures derive from comparisons of monozygotic twins reared apart or together versus dizygotic twins, where genetic similarity predicts IQ correlations more strongly than shared rearing environments.^[68] Heritability estimates increase with age, from around 0.40 in childhood to 0.80 in adulthood, suggesting that genetic influences amplify as individuals mature and select environments congruent with their predispositions.^[69] Genome-wide association studies (GWAS) provide molecular corroboration, identifying hundreds of single-nucleotide polymorphisms (SNPs) associated with intelligence and educational attainment as proxies.^[23] By 2023, large-scale GWAS meta-analyses, such as those involving over 3 million individuals, have yielded polygenic scores (PGS) that predict 10-12% of the variance in IQ and up to 15% in cognitive performance within independent samples.^[31] These PGS outperform twin-study predictions in within-family designs, isolating genetic effects from confounding family-wide environments and confirming causal genetic influence on cognitive traits.^[31] Intelligence appears highly polygenic, involving thousands of variants each with small effects, rather than rare high-impact mutations, aligning with quantitative genetic models.^[23] Neuroimaging and physiological evidence further links genetic variation to cognitive abilities, with heritable brain structures—such as cortical thickness, white matter integrity, and overall volume—correlating 0.3-0.4 with IQ.^[33] Functional MRI studies show that higher-IQ individuals exhibit more efficient neural activation patterns during problem-solving, patterns that are partially heritable and genetically correlated with PGS for intelligence.^[33] Adoption studies, including the Colorado Adoption Project, reveal that biological parents' IQ predicts adoptees' cognitive outcomes more than adoptive parents', underscoring direct genetic transmission over postnatal environment.^[23] While gene-environment interactions exist, such as genotype-specific responses to enriched education, the predominant pattern is that genetic variance explains most stable individual differences in intelligence after accounting for measurement error.^[70] Academic sources emphasizing environmental determinism often underweight these findings due to ideological preferences for malleability narratives, yet the convergence of classical, molecular, and neuroscientific data supports substantial biological causation.^[70]

Personality and Behavioral Traits

Twin studies consistently estimate the heritability of major personality dimensions, such as those in the Big Five model (Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness), at 40-60% of variance explained by genetic factors.^[71] For instance, a study of monozygotic and dizygotic twins reported broad genetic influences of 41% for Neuroticism, 53% for Extraversion, 61% for Openness, 41% for Agreeableness, and comparable levels for Conscientiousness.^[72] These estimates derive from comparing trait similarities between identical twins reared apart or together versus fraternal twins, isolating additive genetic effects from shared environment, which often accounts for minimal variance (typically under 10%).^[73] Behavioral traits linked to personality, such as aggression and impulsivity, show similar genetic contributions. Aggressive behaviors exhibit heritability of 50-65%, with genetic factors explaining roughly half to two-thirds of individual differences in childhood and adolescence.^[74] Impulsivity heritability rises from about 30% in early adolescence to 51% by mid-teens, indicating developmental amplification of genetic influences.^[75] Antisocial behavior, often overlapping with low Agreeableness and high Neuroticism, has a heritability around 40%, predominantly from non-shared environmental effects alongside genetics, with no significant shared family environment role.^[76] Genome-wide association studies (GWAS) provide molecular corroboration, identifying hundreds of genetic loci associated with personality facets. A 2024 GWAS meta-analysis linked 254 genes to Big Five traits, underscoring polygenic architecture where thousands of variants contribute small effects.^[77] Recent large-scale analyses (2020-2025) estimate SNP-based heritability at 4.8-9.3% for these traits, capturing only a fraction of twin-study estimates due to incomplete variant coverage and gene-environment interactions, yet confirming causal genetic roles over pure environmental determinism.^[78] These findings counter claims of negligible biological bases, as polygenic scores predict real-world outcomes like educational attainment tied to Conscientiousness.^[79]

Sex Differences and Sexual Orientation

Biological sex differences arise primarily from genetic and hormonal factors, with males possessing XY chromosomes and higher testosterone levels influencing brain development and behavior from prenatal stages.^[80] These differences manifest in average variations in cognitive abilities, such as females outperforming males in verbal memory and fluency tasks, while males show advantages in spatial rotation and arithmetical reasoning, with effect sizes ranging from moderate (d ≈ 0.5–0.6) to small across meta-analyses.^[81] Brain imaging studies reveal sex-specific patterns in regional volumes and connectivity, including larger amygdalae in males and thicker cortices in females for language-related areas, attributable to both direct genetic effects on sex chromosomes and gonadal hormone exposure.^[82] ^[83] Evolutionary pressures further underscore these dimorphisms, as evidenced by consistent mate preferences across 37 cultures: women prioritize cues of resource provision and status in partners (e.g., earning potential, ambition), reflecting higher parental investment costs, whereas men emphasize physical attractiveness and youth as fertility indicators.^[84] ^[85] Behavioral traits like greater male variability in aggression and risk-taking, linked to testosterone-mediated neural pathways, align with sexual selection for competitive mate acquisition.^[80] Genetic analyses indicate that while sex effects on gene expression are modest genome-wide, they disproportionately affect brain tissues via transcription factors, contributing to dimorphic phenotypes without complete overlap in male-female genetic architectures for traits like height or cognition.^[86] ^[87] Sexual orientation exhibits partial heritability, with twin studies demonstrating higher concordance for same-sex attraction in monozygotic twins (approximately 30–50% for males) compared to dizygotic twins (10–20%), suggesting genetic influences accounting for 30–40% of variance after controlling for shared environment.^[88] ^[89] Genome-wide association studies (GWAS) identify polygenic signals, including variants on chromosomes influencing olfactory receptors and hormone regulation, though no single "gay gene" explains more than a fraction of cases, with environmental prenatal factors like fraternal birth order modulating expression via maternal immune responses.^[90] ^[91] Family pedigree data reinforce familial aggregation, with male homosexuality showing linkage to Xq28 markers in some cohorts, indicating a biological substrate resistant to purely social explanations.^[92] These findings counter environmental determinism, as heritability persists across cultures and despite varying social acceptance, though gene-environment interactions, such as androgen exposure, likely amplify predispositions.^[93]

Group-Level Differences

Biological determinism extends to explanations of average differences in traits between genetically distinct population groups, such as those categorized by ancestry (e.g., East Asian, European, sub-Saharan African), where genetic variation contributes alongside environmental factors. Observed disparities in cognitive performance, particularly intelligence as measured by IQ tests, show consistent patterns across diverse datasets: East Asians averaging approximately 105, Europeans 100, and sub-Saharan Africans 70–85, with U.S. Black-White gaps at 15 points persisting over decades despite socioeconomic controls.^[94]^[95] These differences align with evolutionary pressures on life-history traits, including brain size and maturation rates, where genetic factors explain a substantial portion beyond cultural or nutritional variances.^[94] Transracial adoption studies provide causal evidence against purely environmental accounts, as differences endure in shared rearing environments. In the Minnesota Transracial Adoption Study, Black children adopted by White upper-middle-class families had an average IQ of 89 at age 17, compared to 106 for White adoptees and 99 for biological children of adoptive parents, indicating that enriched environments narrow but do not eliminate gaps.^[96]^[97] Similar patterns emerge in other datasets, such as Korean adoptees in Belgium scoring 112–119, exceeding European norms despite early deprivation, underscoring ancestry's role over postnatal conditions.^[97] Genome-wide association studies (GWAS) further support genetic causation, with polygenic scores (PGS) for educational attainment—correlating 0.3–0.4 with IQ—varying systematically by ancestry: higher in Europeans than Africans, predicting cross-population outcomes even after ancestry principal components adjustment.^[98]^[99] For behavioral traits like personality, group differences show partial genetic underpinnings, though data are sparser than for cognition. Heritability of Big Five traits ranges 40–60% within populations, with alleles linked to extraversion or neuroticism differing in frequency across ancestries, potentially contributing to variances in impulsivity or aggression rates.^[26] For instance, alleles associated with executive function and self-regulation, which covary with ancestry-informative markers, align with observed disparities in crime or time preference between groups, resisting full equalization by policy interventions.^[18] Critics often attribute such patterns to systemic bias, yet empirical reviews, including meta-analyses of adoptee outcomes and genomic data, indicate 50–80% genetic liability for Black-White IQ gaps, challenging environmental monocausalism.^[94]^[100] Mainstream resistance, prevalent in academia despite mounting GWAS evidence, reflects ideological priors over data, as polygenic findings replicate across independent cohorts.^[99]

Gene-Environment Interplay

Evidence of Interaction Effects

Gene-environment interactions (GxE) occur when genetic influences on traits are moderated by environmental factors, such that the expression of genetic variance depends on the level or quality of the environment.^[101] In behavioral genetics, these interactions challenge strict additive models by demonstrating that genetic effects can be amplified, suppressed, or altered by contextual variables, though they do not negate the foundational role of genetic factors in trait variance.^[102] Empirical evidence from twin, adoption, and molecular studies supports GxE across cognitive, personality, and behavioral domains relevant to biological determinism. For cognitive abilities, twin studies reveal that heritability of intelligence quotients (IQ) increases with socioeconomic status (SES), as predicted by the Scarr-Rowe hypothesis, which posits greater genetic expressivity in enriched environments. A 2021 analysis of the U.S. Health and Retirement Study found that polygenic scores for educational attainment predicted IQ more strongly in higher parental SES groups, with heritability rising from lower to higher SES strata.^[103] Similarly, Eric Turkheimer's 2003 study of 7-year-old twins reported IQ heritability of approximately 0.72 in high-SES families versus 0.10 in low-SES families, attributing the difference to environmental constraints limiting genetic potential in deprived settings.^[104] However, replications have been inconsistent, with some large-scale genomic data showing no SES moderation for educational outcomes.^[105] In personality and behavioral traits, the monoamine oxidase A (MAOA) gene exemplifies GxE for aggression. Individuals with the low-activity MAOA variant (MAOA-L), which impairs serotonin and norepinephrine degradation, exhibit heightened antisocial behavior when exposed to childhood maltreatment, but not in its absence.^[106] Caspi et al.'s 2002 Dunedin cohort study (n=1,037) demonstrated that maltreated males with MAOA-L had a 44% prevalence of conduct disorder, compared to 21% for high-activity variants, establishing a replicated interaction effect.^[107] Experimental paradigms, such as provocation tasks, further confirm that MAOA-L carriers display increased reactive aggression under social stress, underscoring how environmental triggers interact with genetic liability.^[108] These interaction effects extend to other traits, such as neuroticism, where genomic analyses indicate that genetic variance is partially obscured by gene-environment correlations, yet emerges more prominently in stable environments.^[109] Overall, while GxE highlights environmental modulation, meta-analyses affirm that genetic factors account for 30-80% of variance in complex traits, with interactions often revealing greater genetic influence in optimal conditions rather than environmental override.^[102]^[110]

Predominance of Genetic Variance

Twin studies and meta-analyses consistently demonstrate that genetic factors account for a substantial majority of the variance in many human traits, particularly those of behavioral and cognitive significance, with heritability estimates often exceeding 50%. A comprehensive meta-analysis of over 17,000 traits from 50 years of twin studies found an average heritability of 49% across all domains, with behavioral traits clustering higher within functional categories such as cognition and personality.^[67] For intelligence, heritability rises from approximately 20% in infancy to 80% by late adolescence and adulthood, as evidenced by longitudinal twin studies, indicating that genetic influences predominate over shared environmental factors, which diminish to near zero in maturity.^[15]^[111] In personality traits, broad heritability estimates range from 40% to 60%, with genetic variance explaining more individual differences than shared family environments, which contribute minimally after accounting for genetic confounds.^[3] Genome-wide complex trait analysis (GCTA) corroborates twin study findings for intelligence, estimating heritability at around 50%, though lower than twin estimates due to capturing only common SNPs; this still underscores genetic predominance, as polygenic scores derived from such data predict trait variance across diverse populations and environments.^[111] These patterns hold despite gene-environment interactions, as the additive genetic component remains the largest source of variance in quantitative genetic models fitted to twin and family data.^[112] The predominance of genetic variance is further supported by the low explanatory power of shared environmental effects in adulthood for most heritable traits, where non-shared environments and measurement error account for the remainder rather than systematic family or cultural influences.^[3] This empirical pattern challenges models emphasizing environmental determinism, as adoption studies show that biological relatedness predicts outcomes better than rearing environment alone, with correlations for IQ in adult adoptees aligning closely with genetic expectations.^[111] Overall, these findings from rigorously controlled designs indicate that genetic variance is the primary driver of individual differences in traits central to biological determinism.^[67]

Critiques of Pure Environmentalism

Twin and adoption studies have provided robust evidence against the notion that environmental factors alone determine complex traits such as intelligence and personality, demonstrating substantial genetic contributions even when rearing environments are equated. Identical twins reared apart exhibit striking similarities in IQ and personality traits, with correlations often exceeding those of fraternal twins reared together, indicating heritability estimates for adult IQ ranging from 50% to 80%.^[111] Adoption studies further corroborate this, showing that adopted children's IQs correlate more strongly with biological parents than adoptive ones, with heritability estimates around 42% in such designs.^[14] These findings challenge pure environmentalism by isolating genetic effects from shared family environments, revealing that variance in traits persists independently of postnatal nurture.^[23] Heritability of intelligence increases linearly across the lifespan, from approximately 20% in infancy to 66% by late adolescence and up to 80% in adulthood, suggesting that as individuals select environments matching their genetic predispositions, genetic influences amplify while shared environmental effects diminish to near zero.^[113] For personality traits, similar patterns emerge, with broad heritability estimates of 40-50% from large-scale twin registries, underscoring that innate dispositions shape behavioral outcomes beyond mere conditioning.^[23] Critics of pure environmentalism, such as behavioral geneticists, argue that these developmental trends refute the blank slate hypothesis, as environmental uniformity fails to erase genetic variance.^[114] Environmental interventions aimed at equalizing outcomes, such as early childhood education programs, often yield temporary IQ gains that fade out within a few years, failing to close persistent gaps in cognitive abilities. Meta-analyses of interventions like Head Start reveal initial boosts of 4-7 IQ points that dissipate by school entry, attributable to non-genetic factors rather than overriding heritability.^[115] This fadeout effect aligns with evidence from adoption and immigration studies, where initial environmental improvements do not sustain elevated performance, implying genetic constraints on malleability.^[110] Such results highlight the causal realism of genetic limits, as pure environmentalist models predict enduring equalization absent, contradicted by longitudinal data tracking thousands of participants.^[116] Despite these empirical patterns, resistance to acknowledging genetic roles persists in some social science literature, potentially influenced by ideological commitments to environmental determinism, though behavioral genetics prioritizes replicable variance partitioning over narrative preferences.^[117] High-quality genomic studies, including genome-wide complex trait analysis, estimate intelligence heritability at 30-50% using unrelated individuals, bridging classical twin data with molecular evidence and further undermining claims of negligible innate influences.^[118]

Criticisms and Rebuttals

Ideological Objections

Ideological objections to biological determinism often stem from egalitarian doctrines that prioritize environmental explanations for human differences, viewing genetic influences as incompatible with ideals of social justice and malleability. Critics contend that emphasizing heredity justifies existing inequalities, such as class or racial disparities, by portraying them as biologically inevitable rather than products of systemic oppression. For instance, Marxist biologists like Richard Lewontin and Steven Rose argued in their 1984 book Not in Our Genes that biological determinism serves bourgeois ideology by naturalizing capitalist hierarchies and diverting attention from economic restructuring as the path to equality.^[119]^[120] These objections frequently invoke historical abuses, equating any genetic hypothesis with eugenics or scientific racism, despite distinctions between descriptive science and prescriptive policy. Stephen Jay Gould, in The Mismeasure of Man (1981, revised 1996), critiqued hereditarian views on intelligence as reifying social hierarchies, asserting that such theories impose "a theory of limits" on human potential and undermine progressive reforms.^[121] Gould's framework, influenced by dialectical materialism, portrayed biological determinism as a conservative force that constrains societal choice by implying fixed outcomes.^[122] A related strand draws from blank slate empiricism, which denies innate psychological traits to preserve notions of the "noble savage" uncorrupted by society. Proponents of this view, prevalent in mid-20th-century social sciences, objected to heredity research as fostering fatalism and excusing personal or collective responsibility. Steven Pinker has noted that such resistance reflects fears that genetic explanations enable racism, revive eugenics, undermine free will, or erode self-determination narratives, often leading to selective dismissal of heritability evidence in favor of cultural constructivism.^[123]^[124] Historically, these ideologies manifested in politically enforced rejections of genetics, as in the Soviet Union's Lysenkoism (1930s–1960s), where Marxist orthodoxy supplanted empirical biology with environmental Lamarckism to align with proletarian upliftment ideals, resulting in famines and scientific stagnation.^[125] In contemporary academia, similar dynamics persist, with surveys indicating that left-leaning scholars disproportionately view biological determinism as an ideological weapon, often prioritizing moral intuitions over twin studies or GWAS data showing substantial genetic variance in traits like intelligence (heritability estimates of 50–80% in adulthood).^[126]^[127] Such objections, while rooted in anti-hierarchical commitments, have been critiqued for conflating probabilistic genetic influences with absolute predestination, thereby hindering causal realism in favor of aspirational environmentalism.^[128]

Methodological Disputes

The classical twin design, a cornerstone method for estimating heritability in behavioral genetics, assumes the equal environments assumption (EEA), positing that monozygotic (MZ) twins, who share nearly 100% of their genes, experience environmental similarities comparable to dizygotic (DZ) twins, who share about 50%. Violations of this assumption, such as greater parental treatment similarity for MZ twins due to their physical resemblance, could inflate heritability estimates by attributing shared environmental effects to genetics. Empirical tests, including surveys of twin-specific experiences, have identified EEA violations for traits like political ideology and religiousness, where MZ-DZ environmental correlations differ significantly, potentially overestimating genetic variance by 10-20% in affected domains.^[129]^[130] However, meta-analyses across cognitive abilities, personality, and psychopathology consistently find minimal systematic bias, as measured environmental similarities align closely between twin types for these traits, supporting the EEA's approximate validity in large samples.^[131]^[132] A related methodological contention involves genotype-environment correlations (rGE) and interactions (GxE), which challenge the additivity assumed in basic variance partitioning models. Critics argue that passive rGE—where parental genotypes influence both offspring genes and environments—confounds estimates, as does evocative rGE, where genetically influenced traits elicit similar environments. For example, children with higher genetic propensities for intelligence may receive enriched educational inputs, misclassifying environmental variance as genetic. Advanced structural equation models incorporating rGE, applied to longitudinal twin data, reveal that while these effects explain 10-30% of phenotypic variance in traits like IQ, they do not substantially reduce broad-sense heritability, which remains 50-80% across populations.^[20]^[133] Simulations demonstrate that ignoring rGE leads to underestimation of shared environment rather than overestimation of genetics in most cases.^[134] The "missing heritability" paradox further fuels disputes, as twin/family studies yield high heritability (e.g., 40-60% for educational attainment) while genome-wide association studies (GWAS) explain only 10-20% via identified single-nucleotide polymorphisms (SNPs). This gap, observed since large-scale GWAS in 2007, prompts debates over whether quantitative genetic methods overestimate narrow-sense heritability due to non-additive effects or if molecular approaches underestimate via incomplete variant capture, given polygenic architectures involving thousands of loci. Recent polygenic score advancements, integrating GWAS hits, now predict 10-15% of variance in holdout samples for complex traits, bridging part of the divide, though rare variants and structural mutations likely account for the remainder.^[134]^[135] Critics from developmental psychology contend such discrepancies invalidate twin-based inferences, but causal inference from adoption studies and sibling designs corroborates twin findings, isolating genetic effects independently of molecular data.^[136] Assortative mating and cultural transmission represent additional points of contention, as non-random partner selection for heritable traits (e.g., 0.3-0.4 correlations for education) amplifies genetic variance across generations, potentially biasing population-level estimates. Models adjusting for these factors, using extended twin-family designs, show they increase rather than decrease genetic resemblance, reinforcing heritability robustness. Methodological responses include hybrid designs combining GWAS with twin data, which partition variance more precisely and mitigate assumptions, yielding consistent evidence for predominant genetic causation in individual differences despite environmental modulations.^[137]^[138]

Empirical Responses and Verifiable Counter-Evidence

Twin and adoption studies consistently demonstrate high heritability for intelligence, with estimates ranging from 57% to 73% in adults based on early twin research and up to 80% from behavioral genetics analyses.^[23]^[33] A 2021 adoption study of 486 families estimated IQ heritability at 0.42 (95% CI: 0.21-0.64), finding negligible influence from adoptive parents' environments on offspring IQ, underscoring genetic predominance over shared family factors.^[14] These designs control for genetic confounding, revealing that monozygotic twins reared apart exhibit IQ correlations comparable to those reared together, countering claims that familial similarity arises solely from nurture.^[68] Genome-wide association studies (GWAS) provide molecular verification, with polygenic scores derived from large-scale genotyping explaining 11-16% of variance in educational attainment and correlating with IQ measures, independent of socioeconomic status.^[139]^[98] A 2024 meta-analysis of polygenic scores for intelligence confirmed their predictive validity across datasets, attributing differences to thousands of genetic variants rather than environmental artifacts, thus rebutting assertions that heritability estimates reflect methodological flaws like range restriction.^[30] Transracial adoption studies offer direct tests of environmental equalization. In the Minnesota Transracial Adoption Study follow-up, black children adopted by white families at age 17 averaged IQ scores of 89, persisting below white adoptee (106) and biological white sibling (109) means, indicating racial IQ gaps endure despite enriched rearing environments.^[96]^[140] This refutes pure environmentalism, as socioeconomic interventions failed to close gaps to adoptive family levels. Early childhood programs like Head Start yield short-term cognitive boosts but no sustained IQ gains into adolescence or adulthood, with meta-analyses showing fade-out of effects on intelligence while achievement benefits vary.^[141] Longitudinal evaluations confirm that such interventions alter behaviors or schooling access modestly but do not override genetic baselines, as evidenced by unchanged heritability trajectories post-enrollment.^[142] These null long-term IQ findings challenge nurture-only models, which predict malleability through enriched inputs absent in heritability data.

Societal and Policy Implications

Historical Misapplications (e.g., Eugenics)

The eugenics movement, originating in the late 19th century, represented a prominent historical misapplication of biological determinism by advocating state intervention to selectively breed humans based on perceived genetic quality. British scientist Francis Galton coined the term "eugenics" in 1883, defining it as the study of agencies under social control that could improve the hereditary qualities of future generations through positive measures like encouraging reproduction among the "fit" and negative measures like restricting it among the "unfit."^[143] Galton's ideas drew from observations of familial patterns in achievement and extended Charles Darwin's principles of natural selection to human society, positing that traits such as intelligence and moral character were largely heritable and could be optimized societally.^[48] However, this framework overstated genetic determinism by downplaying environmental influences and relying on rudimentary statistical methods that conflated correlation with causation, leading to policies that treated complex human variation as fixed and breedable like livestock.^[10] In the United States, eugenics gained traction in the early 20th century, influencing legislation for compulsory sterilization of individuals deemed genetically inferior, such as those labeled feebleminded, criminal, or epileptic. Indiana enacted the first such law in 1907, followed by over 30 states by the 1920s, resulting in approximately 60,000 to 70,000 forced sterilizations by the mid-20th century, disproportionately affecting women, the poor, and minorities.^[56] The 1927 Supreme Court case Buck v. Bell upheld Virginia's sterilization statute, authorizing the procedure on Carrie Buck, a young woman institutionalized under questionable pretenses of hereditary feeblemindedness; Justice Oliver Wendell Holmes famously wrote, "Three generations of imbeciles are enough," equating the policy to compulsory vaccination.^[144] These programs were supported by organizations like the Eugenics Record Office, which promoted flawed IQ testing and family pedigrees as evidence of genetic unfitness, ignoring socioeconomic confounders and the polygenic, environmentally modulated nature of traits like intelligence.^[56] Nazi Germany's eugenics policies escalated these misapplications into systematic genocide, drawing inspiration from American models while integrating racial ideology. The 1933 Law for the Prevention of Hereditarily Diseased Offspring mandated sterilization for conditions including schizophrenia and hereditary blindness, affecting over 400,000 people by 1945.^[145] The Aktion T4 program, initiated in 1939, systematically murdered around 70,000 institutionalized disabled individuals via gas chambers and lethal injection under the guise of mercy killing, serving as a testing ground for extermination techniques later used in the Holocaust.^[146] Proponents justified these actions through a deterministic view of biology as dictating racial worth, but the selections relied on arbitrary criteria and pseudoscientific assessments, such as non-lethal traits extrapolated to fatal prognoses, revealing how biological determinism, when fused with state power and unverified hereditarian claims, enabled mass atrocities without empirical validation of purported genetic threats.^[146]

Modern Policy Considerations

In education policy, the substantial heritability of cognitive abilities and educational attainment—ranging from 50% to 80% based on twin and adoption studies—implies that interventions assuming high environmental malleability may yield diminishing returns, as genetic factors predominantly explain variance in outcomes among individuals in similar environments.^[147]^[148] This has informed debates over ability-based tracking versus uniform curricula, with evidence from longitudinal genomic analyses showing polygenic scores for educational attainment predicting later achievement independently of socioeconomic status, suggesting policies like selective admissions or targeted enrichment could optimize resource use without exacerbating inequality.^[149] Critics, often from egalitarian perspectives, argue against such approaches to avoid reinforcing disparities, yet empirical data indicate that denying genetic contributions leads to over-optimistic expectations for broad equalization efforts.^[150] In criminal justice, behavioral genetics reveals genetic influences accounting for 30-50% of variance in antisocial traits and up to 50% in aggressive behavior, as meta-analyses of genetically informative designs demonstrate.^[151]^[152] Polygenic risk scores integrating these factors have shown predictive power for recidivism and offending, even after controlling for environmental confounders, prompting policy explorations in risk assessment and rehabilitation tailored to gene-environment interactions, such as early interventions for high-risk youth.^[153]^[154] Implementation remains contentious, with ethical concerns over determinism cited in legal reviews, though proponents contend that ignoring genetics perpetuates ineffective uniform sentencing, as seen in U.S. and European court discussions since the 2010s.^[155] Academic sources, while peer-reviewed, frequently exhibit caution due to ideological pressures against biological explanations, yet adoption studies provide robust counter-evidence to pure environmentalism.^[156] Broader social policies, including welfare and employment, increasingly consider "personalized" approaches informed by genetics, where behavior genetic findings enable targeted supports—e.g., vocational training aligned with heritable aptitudes—rather than one-size-fits-all programs assuming full environmental determinism.^[157] A 2022 review of genomic contributions to policy highlights potential in employment matching via genetic predictors of traits like conscientiousness, which explain 20-40% of variance, though adoption lags due to fears of genetic fatalism.^[154]^[158] These considerations underscore a shift toward causal realism, prioritizing interventions that leverage rather than deny biological realities, as evidenced by pilot programs in predictive analytics for social services in the UK and U.S. since 2020.^[159]

Future Research Directions

Future research in biological determinism emphasizes refining estimates of genetic contributions to complex traits through integration of quantitative and molecular genetics, particularly via polygenic scores that aggregate effects from thousands of genetic variants. These scores have shown increasing predictive accuracy for educational attainment and cognitive abilities, with correlations rising from 0.10 in early implementations to around 0.40 in recent large-scale genome-wide association studies (GWAS).^[160] Ongoing efforts aim to extend this to personality and psychopathology, addressing limitations like population stratification by incorporating diverse ancestries in biobanks such as the UK Biobank, which analyzed over 500,000 participants by 2023.^[160] A key direction involves dissecting gene-environment interactions (GxE) using advanced statistical models that account for non-linear effects and longitudinal data, moving beyond additive assumptions in twin studies. Recent methodological innovations, including machine learning approaches for high-dimensional environmental exposures, promise to quantify how genetic predispositions moderate responses to factors like socioeconomic status or early adversity, with simulations indicating up to 20% additional variance explained in disease outcomes.^[161] Large cohort studies, such as those leveraging electronic health records integrated with genotyping, will test causal pathways via Mendelian randomization, isolating genetic effects from confounding environmental correlations.^[162] Emerging technologies like CRISPR-based editing and single-cell epigenomics offer experimental validation of heritability mechanisms, potentially elucidating how germline variants influence developmental trajectories in model organisms and human induced pluripotent stem cells. By 2025, AI-driven analyses of multi-omics data are projected to model dynamic gene expression changes, clarifying the "nature of nurture" where shared environments amplify genetic variance over time, as observed in heritability estimates doubling from childhood to adulthood for intelligence.^[163] These approaches prioritize causal realism by prioritizing interventions that target modifiable genetic influences, while acknowledging persistent challenges in measuring elusive environmental variables comprehensively.^[164]

References

[1]
(PDF) Biological determinism - ResearchGate
Mar 31, 2019 · Biological determinism is the tendency to view human social phenomena (at the individual, group and societal level) as the products of biological causes.
[2]
Biological Determinism: Definition and Examples - ThoughtCo
Aug 19, 2019 · Biological determinism is the idea that an individual's characteristics and behavior are dictated by some aspect of biology, like genes.
[3]
Beyond Heritability: Twin Studies in Behavioral Research - PMC - NIH
The heritability of human behavioral traits is now well established, due in large measure to classical twin studies. We see little need for further studies ...
[4]
[PDF] Heritability and Biological Explanation - OpenScholar
It is generally assumed that the genetic and biological ques- tions are related, especially in the sense that the heritability of behavior is taken as evidence ...
[5]
(PDF) Biological determinism - ResearchGate
Biological determinism is the tendency to view human social phenomena (at the individual, group, and societal level) as the products of biological causes.
[6]
Biological hierarchy, determinism, and specificity - Research Features
May 1, 2021 · “The foundations of life and medical research can be further developed using the concepts of biological hierarchy, determinism, and specificity.
[7]
The Germ-Plasm: a Theory of Heredity (1893), by August Weismann
Jan 26, 2015 · In The Germ Plasm, Weismann rejects the theory and argues that acquired characteristics are traits of the soma cells, and the hereditary ...
[8]
ESP Digital Books: The Germ-Plasm: A Theory of Heredity
Genetic information cannot pass from soma to germ plasm and on to the next generation. Biologists refer to this concept as the Weismann barrier. This idea, if ...
[9]
The End of Behavioral Genetics? - PMC - NIH
Galton believed inherited factors had a substantial influence on individual differences in behavior. As the quote indicates, however, he did not believe that ...
[10]
The power of heredity and the relevance of eugenic history
What was eugenics? The standard account of eugenics begins with the definition the English gentleman Francis Galton gave to the word in an 1883 essay.
[11]
Rehabilitating Galton | Heredity - Nature
Oct 25, 2004 · Further, Galton and his followers recognized these points of tension and vigorously opposed Mendelian genetics in the early 1900s. Since the ...<|separator|>
[12]
The genomic case against genetic determinism - PMC - NIH
Feb 27, 2024 · Animal studies reveal that the molecular wiring of the brain can be altered by heredity, the environment, and their interaction.
[13]
Misrepresentations of Evolutionary Psychology in Sex and Gender ...
E2) Biological Determinism/Dichotomy between Nature & Nurture. (1) The assertion that EPs contend that biology determines or can explain all human behavior. (2) ...
[14]
Genetic and environmental contributions to IQ in adoptive and ...
Explaining the increasing heritability of cognitive ability across development: A meta-analysis of longitudinal twin and adoption studies. Psychological ...
[15]
Explaining the Increasing Heritability of Cognitive Ability Across ...
More recently, Bergen, Gardner, and Kendler (2007) conducted a meta-analysis of six studies and reported an increase in heritability from approximately 55% at ...
[16]
Genetic and environmental contributions to IQ in adoptive and ...
We estimated genetic and environmental effects on adulthood IQ in a unique sample of 486 biological and adoptive families.
[17]
[PDF] Heritability × SES Interaction for IQ: Is it Present in US Adoption ...
Aug 26, 2021 · Data from two such studies, the Texas and the Colorado Adoption Projects, were examined, involving 238–469 adopted children given IQ tests at.
[18]
The genetics of human personality - PMC - NIH
Twin and family studies have demonstrated that personality traits are moderately heritable, and can predict various lifetime outcomes, including psychopathology ...
[19]
The Heritability of Personality is not Always 50%: Gene-Environment ...
The heritability of personality is not always 50%, as it is influenced by gene-environment interactions and parenting, which can act as a moderator.
[20]
Conventional twin studies overestimate the environmental ... - Nature
Jul 17, 2023 · Our best-fitting model estimated heritability at 51%, up 17 percentage points from our CTD estimate of 34%. This difference aligns with the 17- ...
[21]
Family environment and the malleability of cognitive ability - PNAS
Mar 23, 2015 · The mean IQ of the adopted group was 110.6, compared with 94.5 in the nonadopted siblings. In contrast to the reliably positive effects of ...
[22]
Polygenic scores: prediction versus explanation | Molecular Psychiatry
Oct 22, 2021 · Polygenic scores will never predict complex traits with perfect precision because heritabilities are about 50% for most behavioural traits [22] ...
[23]
The new genetics of intelligence - PMC - PubMed Central
Polygenic scores derived from GWAS of intelligence can now predict 4% of the variance in intelligence. More than 10% of the variance in intelligence can be ...
[24]
Intelligence Polygenic Score Is More Predictive of Crystallized ...
May 5, 2023 · We found that crystallized measures were more strongly associated with both polygenic predictors than were fluid measures.<|separator|>
[25]
The Genetics of Intelligence (24.01.2025)
Jan 24, 2025 · Results: Genome-wide association studies (GWAS) have shown that certain gene loci are associated with intelligence, as well as with educational ...
[26]
Heritability estimates of the Big Five personality traits based on ... - NIH
Jul 14, 2015 · According to twin studies, the Big Five personality traits have substantial heritable components explaining 40–60% of the variance, ...
[27]
Uncovering the complex genetics of human character - Nature
Oct 3, 2018 · Human personality is 30–60% heritable according to twin and adoption studies. Hundreds of genetic variants are expected to influence its ...
[28]
Childhood behaviour problems show the greatest gap between DNA ...
Dec 12, 2017 · Evidence from many twin, family, and adoption studies points to significant genetic influence, with heritability estimates ranging from ~ 40% ...
[29]
A genome-wide association study for extremely high intelligence
Jul 4, 2017 · A genome-wide polygenic score constructed from the GWA results accounted for 1.6% of the variance of intelligence in the normal range in an ...
[30]
DNA and IQ: Big deal or much ado about nothing? – A meta-analysis
Twin and family studies have shown that about half of people's differences in intelligence can be attributed to their genetic differences, with the ...
[31]
Polygenic Score Prediction Within and Between Sibling Pairs for ...
Jun 23, 2025 · The IQ3 polygenic score was used to predict intelligence and cognitive abilities, including general cognitive ability (g) and its verbal and ...
[32]
The Genetics of Intelligence - PMC - PubMed Central - NIH
Genetic factors explain a considerable fraction of inter-individual differences in intelligence. For many years, research on intelligence was limited to ...
[33]
Genetic variation, brain, and intelligence differences - Nature
Feb 2, 2021 · In such studies, heritability estimates are about 20–30% (SEs < 1% in recent studies) [31, 32]. The lower estimates of heritability found ...
[34]
How Genes Shape Personality Traits: New Links Are Discovered
Sep 9, 2024 · By discovering new genetic variations associated with personality traits, researchers at Yale School of Medicine have taken a step toward ...Missing: 2000-2025 | Show results with:2000-2025
[35]
Top 10 Replicated Findings from Behavioral Genetics - PMC
By using genetically sensitive designs such as twin studies, behavioral genetics has revealed almost as much about the environment as about genetics. 1. All ...
[36]
The Fourth and Fifth Laws of Behavioral Genetics - Mad In America
Sep 8, 2015 · “All human behavioral traits are heritable.” “The effect of being raised in the same family is smaller than the effect of genes.” “A substantial ...
[37]
Polygenic inheritance, GWAS, polygenic risk scores, and the ... - PNAS
Aug 4, 2020 · Polygenic risk scores that provide an overall estimate of the genetic propensity to a trait at the individual level have been developed using ...Abstract · Genome-Wide Association... · Polygenic Risk Scores
[38]
Bench Research Informed by GWAS Results - PMC - PubMed Central
In this review, we aim to familiarise 'wet biologists' with approaches for the interpretation of GWAS results, to clarify some issues that may seem ...
[39]
The next 10 years of behavioural genomic research - PMC
Nov 4, 2022 · Three transformative developments for behavioural genomic research in the next 10 years are described. First, behavioural genomic research will ...
[40]
Generation, Development, and Ancestral Concepts of Heredity - PMC
Heredity is such a fundamental concept that it is hard to imagine a world where the connection between parents and offspring is not understood.
[41]
Principles and biological concepts of heredity before Mendel
Oct 21, 2021 · Festetics adopted Kant's Vererbung concept in breeding, and postulated that biological heredity is a natural process since traits that are ...
[42]
Galen's Generations of Seeds (Chapter 7) - Reproduction
Galen was, after all, a two-seed man, but his feeble female sperma enacts the sexual hierarchy just as clearly as Aristotle's un-concocted female residue. Galen ...
[43]
Galen's Germ Line - HSS Annual Meeting - All Academic
This paper draws out Galen's unusual place as a theorist of heredity, first within his own intellectual culture and then within the long history of heredity ...
[44]
Heredity - an overview | ScienceDirect Topics
Since antiquity, variations in heredity were frequently explained by environmental factors such as use and disuse or need for a particular characteristic. By ...
[45]
Epigenesis and Preformationism
Oct 11, 2005 · Epigenesis and Preformation are two persistent ways of describing and seeking to explain the development of individual organic form.
[46]
Theories of Biological Development
Jun 3, 2022 · Nature or nurture, epigenesis or preformation, genetic determinism or developmental free will, or is some version of a middle ground possible?
[47]
Contrasting philosophical and scientific views in the long history of ...
The theory of preformation originated in the School of Hippocrates (460-370 BCE). It was the idea of a material continuity between generations, where the embryo ...
[48]
Eugenics: Its Origin and Development (1883 - Present)
Nov 30, 2021 · Eugenics is an immoral and pseudoscientific theory that claims it is possible to perfect people and groups through genetics and the scientific laws of ...
[49]
Francis Galton: Father of the British Eugenics Movement
In his most important book on human characteristics and talents, Inquiries into Human Faculty and Its Development, Galton introduced the word “eugenics,” taken ...
[50]
Social Darwinism | Definition, Uses, & Facts | Britannica
Sep 4, 2025 · Social Darwinism, the theory that human groups and races are subject to the same laws of natural selection as Charles Darwin perceived in plants and animals in ...
[51]
Spencer Introduces Principles of Social Darwinism | Research Starters
Spencer's philosophy proposed that social evolution mirrors biological evolution, suggesting that certain individuals and societies are "more fit" and therefore ...Missing: determinism | Show results with:determinism
[52]
Cesare Lombroso - Simply Psychology
Oct 13, 2025 · Biological Determinism and Reductionism Lombroso claimed that crime could be explained primarily by biology, but this monogenetic determinism ( ...Father of Modern Criminology · Atavism · Measuring Crime · Occasional Criminals
[53]
Cesare Lombroso: an anthropologist between evolution and ... - NIH
Lombroso's anthropological ideas fuelled a heated debate on the biological determinism of human behaviour. Keywords: criminology , criminal anthropology , ...
[54]
The birth of American intelligence testing
Jan 1, 2009 · It was Goddard who created the intelligence testing industry. Thus, he's responsible for popularizing psychological science in America.Missing: century determinism
[55]
Intelligence testing and immigration legislation | Research Starters
Goddard and Lewis Terman adapted these tests, often associating intelligence with racial and biological determinism. This perspective influenced immigration ...
[56]
U.S. Scientists' Role in the Eugenics Movement (1907–1939) - NIH
The practice of forced sterilizations for the “unfit” was almost unanimously supported by eugenicists. The American Eugenics Society had hoped, in time, to ...
[57]
(PDF) From Social Darwinism to Sociobiology - ResearchGate
Aug 7, 2025 · Biological determinism, the theory that human behavior is primarily determined by genetic factors, has sparked extensive debate and controversy ...
[58]
The origins of behavioral genetics - ScienceDirect.com
Mar 11, 2008 · Studies of genes and behavior actually go back to the beginnings of genetics. The end of the era marked by Benzer's life offers a good opportunity to look back.Missing: advances | Show results with:advances
[59]
Celebrating a Century of Research in Behavioral Genetics - PMC - NIH
1970 was a watershed year marking the second 50 years of behavioral genetic research. It was the year that the Behavior Genetics Association was launched and ...Missing: 1950s- | Show results with:1950s-
[60]
How much can we boost IQ and scholastic achievement?
How much can we boost IQ and scholastic achievement? Citation. Jensen, A. R. (1969). How much can we boost IQ and scholastic achievement?
[61]
[PDF] How Much Can We Boost IQ and Scholastic Achievement?
Arthur Jensen argues that the failure of recent compensatory education efforts to produce lasting effects on children's IQ and achievement suggests that the.
[62]
Heritability, IQ, and Education
From studies of monozygotic and dizygotic twins and other data, Jensen estimated the within-group heritability (h 2) of IQ test scores as h 2 ~ 0.7. He ...<|control11|><|separator|>
[63]
[PDF] what is behavioral genetics? - Saylor Academy
Researchers in the field of behavioral genetics study variation in behavior as it is affected by genes, which are the units of heredity passed down from parents ...
[64]
Sociobiology - Stanford Encyclopedia of Philosophy
Nov 11, 2013 · Sociobiology is the study of the biological basis of social behavior, also known as behavioral ecology, using evolutionary theory to understand ...
[65]
[PDF] Sociobiology: The New Synthesis (25th Anniversary Edition)
Sociobiology was brought together as a coherent discipline in. Sociobiology: The New Synthesis (1975), the book now reprinted,.
[66]
Sociobiology on Screen. The Controversy Through the Lens of ...
When the sociobiology debate erupted in 1975, there were almost too many contributions to the heated exchanges between sociobiologists and their critics to ...
[67]
Meta-analysis of the heritability of human traits based on fifty years ...
May 18, 2015 · We report a meta-analysis of twin correlations and reported variance components for 17,804 traits from 2,748 publications including 14,558,903 ...<|separator|>
[68]
IQ differences of identical twins reared apart are significantly ...
In addition, a recent meta-analysis suggests that beyond correlation, increased education has a causative impact on IQ at a rate of between 1 and 5 points ...
[69]
A meta-analysis of 11000 pairs of twins shows that the heritability of...
A meta-analysis of 11000 pairs of twins shows that the heritability of intelligence increases significantly from childhood (age 9) to adolescence (age 12) and ...
[70]
https://pmc.ncbi.nlm.nih.gov/articles/PMC5985927
[71]
Heritability estimates of the Big Five personality traits based on ...
Aug 9, 2025 · According to twin studies, the Big Five personality traits have substantial heritable components explaining 40-60% of the variance, but ...
[72]
Heritability of the big five personality dimensions and their facets
Broad genetic influence on the five dimensions of Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness was estimated at 41%, 53%, 61%, 41% ...
[73]
The five factor model of personality and heritability
First, the tables show that there is a significant heritable component to most of the personality traits for both genders. Only two of the heritability ...
[74]
Genetics of child aggression, a systematic review - Nature
Jun 11, 2024 · It has been found that aggressive behaviors are highly heritable and genetic factors account for roughly 50–65% of the risk of high aggression ...
[75]
Genetics of impulsive behaviour - PMC - PubMed Central - NIH
Heritability increased from 30 to 51 per cent from age 12 to 14 suggesting an increasing role of genetic influence with age.
[76]
Human Aggression Across the Lifespan: Genetic Propensities and ...
The heritability of aggressive behavior based on self-reports is 40% and the nonshared environment accounts for the remaining 60% of the variance. There is no ...
[77]
A genome-wide investigation into the underlying genetic ... - Nature
Aug 12, 2024 · Gene-based association testing revealed 254 genes showing significant association with at least one of the five personality traits.
[78]
Robust inference and widespread genetic correlates from a large ...
May 20, 2025 · We identify 1,257 lead genetic variants associated with personality, including 823 novel variants. Common genetic variants explain 4.8%-9.3% of ...Missing: heritability 2020-2025
[79]
A genome-wide investigation into the underlying genetic ... - NIH
We first used LDSC to calculate SNP-based heritability of each of the five personality traits within the MVP EUR cohort. The SNP-heritability ranges from 4% to ...Results · Mvp Gwas · Gwas And Meta-Analysis
[80]
The Genetics of Sex Differences in Brain and Behavior - PMC
This paper reviews the evidence for direct genetic effects in behavioral and brain sex differences.
[81]
Sex/gender differences in cognitive abilities - ScienceDirect.com
Women tend to display higher verbal abilities, including verbal memory, whereas men exhibit higher spatial and arithmetical skills8–10; a similar pattern has ...
[82]
Sex differences in the brain: Implications for behavioral and ... - NIH
This review focuses on the study of sex differences in the neurobiology of social behavior, memory, emotions, and recovery from brain injury.
[83]
Sex differences in the human brain: a roadmap for more careful ...
Jul 26, 2022 · We review observations that motivate research on sex differences in human neuroanatomy, including potential causes (evolutionary, genetic, and environmental) ...
[84]
Sex differences in human mate preferences: Evolutionary ...
Feb 4, 2010 · Contemporary mate preferences can provide important clues to human reproductive history. Little is known about which characteristics people ...
[85]
[PDF] Sex differences in human mate preferences - UT Psychology Labs
These sex differences may reflect different evolutionary selection pressures on human males and females; they provide powerful cross-cultural evidence of.<|control11|><|separator|>
[86]
The impact of sex on gene expression across human tissues - Science
Sep 11, 2020 · Overall, the effects of sex on gene expression were small, but they were genome-wide and mostly mediated through transcription factor binding.
[87]
Genetic Mechanisms Leading to Sex Differences Across Common ...
We find that all anthropometric traits show less than complete correlation between the genetic contribution to males and females, and find a convincing example ...
[88]
Sexual Orientation in Twins: Evidence That Human Sexual Identity ...
Dec 30, 2023 · If one twin has a same-sex orientation, there is a 30% chance that the second twin will have this same identity. If splitting occurs after day ...
[89]
A short review of biological research on the development of sexual ...
Heritability studies have typically shown significantly greater concordance for same-sex orientation among monozygotic (identical) co-twins compared to ...
[90]
Large-scale GWAS reveals insights into the genetic ... - Science
Twin studies and other analyses of inheritance of sexual orientation in humans has indicated that same-sex sexual behavior has a genetic component.
[91]
Exploring Biological Theories of Homosexuality: A Focus on the X ...
Apr 21, 2025 · This article examines two independent theories, the X-linkage theory and the fraternal birth order effect, which suggest that homosexuality is shaped by ...<|separator|>
[92]
Genome-Wide Linkage Study Meta-Analysis of Male Sexual ... - NIH
Jun 2, 2021 · Introduction. Male homosexuality runs in families, and twin studies have shown that genetic contributions appear to account for a moderate ...
[93]
Full article: The causes of human sexual orientation
Sep 16, 2020 · Genetics. Two main sources of evidence are available in respect of the genetic determinants of sexual orientation: twin studies and molecular ...Genetics · Does It Matter? · NotesMissing: heritability | Show results with:heritability
[94]
[PDF] THIRTY YEARS OF RESEARCH ON RACE DIFFERENCES IN ...
The new evidence reviewed here points to some genetic component in. Black–White differences in mean IQ. The implication for public policy is that the.
[95]
Race and IQ: A Theory-Based Review of the Research in Richard ...
We conclude that the preponderance of evidence demonstrates that in intelligence, brain size, and other life history traits, East Asians average higher than ...
[96]
The Minnesota transracial adoption study: A follow-up of IQ test ...
There were no differences between the transracial adoptees and the biological offspring of the adoptive parents in IQ score change from Time 1 to Time 2.
[97]
Racial IQ Differences among Transracial Adoptees: Fact or Artifact?
Dec 23, 2016 · The studies' results are therefore consistent with a baseline IQ of 100 for Korean adoptees, exaggerated by a Flynn effect of 6 points and an ...
[98]
Polygenic prediction of educational attainment within and between ...
Mar 31, 2022 · A genome-wide polygenic predictor, or polygenic index (PGI), explains 12–16% of EA variance and contributes to risk prediction for ten diseases.
[99]
Genes, Heritability, 'Race', and Intelligence - PubMed Central - NIH
Feb 15, 2022 · The evidence is overwhelming that genetic variation at many genomic loci substantially influences variation in intelligence and other cognitive ...
[100]
James Watson's most inconvenient truth: Race realism and the ...
On the basis of the 10 research categories listed below, we concluded that the mean 15-point Black–White IQ difference in the US is about 80% heritable and that ...
[101]
Gene–environment correlations: a review of the evidence and ...
Overall, the evidence from twin and adoption studies suggests that rGEs are mediated by heritable personality and behavioral characteristics. Because genetic ...
[102]
Genetics and intelligence differences: five special findings - Nature
Sep 16, 2014 · Explaining the increasing heritability of cognitive ability across development: A meta-analysis of longitudinal twin and adoption studies.
[103]
Evidence for the Scarr-Rowe Effect on Genetic Expressivity in the ...
Apr 5, 2021 · The Scarr-Rowe effect is a gene × environment interaction, which is characterized by a negative association between exposure to low ...Missing: hypothesis | Show results with:hypothesis
[104]
The paradox of intelligence: Heritability and malleability coexist in ...
The paradox of intelligence: Heritability and malleability coexist in hidden gene-environment interplay.
[105]
No evidence of the Scarr-Rowe hypothesis for educational outcomes
However, the evidence regarding the Scarr-Rowe hypothesis is highly inconclusive, as reviewed in Table A1 in the Appendix. PGIs for cognitive and noncognitive ...
[106]
The role of monoamine oxidase A in the neurobiology of aggressive ...
The best-documented gene implicated in aggression is MAOA (Monoamine oxidase A), which encodes the key enzyme for the degradation of serotonin and ...
[107]
Monoamine oxidase A gene (MAOA) predicts behavioral aggression ...
Thus, subjects with MAOA-L were hypothesized to behave more aggressively, but only when significantly provoked (i.e., a gene by environment interaction).
[108]
novel insights into monoamine oxidases (MAOs) and aggression
Feb 18, 2021 · Genetic studies in humans provide evidence that MAO-A is linked to aggression but only when other environmental factors are also present during ...
[109]
Genomic analysis of family data reveals additional genetic effects on ...
Jan 10, 2018 · In our models, genetic variants in low LD with genotyped SNPs explain over half of the genetic variance in intelligence, education, and neuroticism.<|separator|>
[110]
The Paradox of Intelligence: Heritability and Malleability Coexist in ...
Gene-environment correlation means that individuals with particular genotypes for a trait are more likely to experience particular relevant environments.
[111]
Genetics and intelligence differences: five special findings - PMC
Sep 16, 2014 · Similar to other complex traits, GCTA heritability estimates for intelligence are about half the heritability estimates from twin studies.
[112]
A twin-family study of general IQ - ScienceDirect.com
Twin studies in children estimate the contribution of genetic effects to the variability in intelligence at 25% to 50%. Part of the remaining variance is due to ...
[113]
The heritability of general cognitive ability increases linearly from ...
The heritability of general cognitive ability increases significantly and linearly from 41% in childhood (9 years) to 55% in adolescence (12 years) and to 66% ...
[114]
Empirical Science for the Spotless Mind
Aug 30, 2005 · Perhaps the most devastating argument against the blank slate comes from neuroscience, where research by APS William James Fellow Award ...
[115]
The environment in raising early intelligence: A meta-analysis of the ...
Previous investigations into the fadeout effect, however, have largely been qualitative and consisted of demonstrating how a few big-name studies failed to have ...
[116]
IQ scores decline after an intervention ends. - ResearchGate
Extensive research to increase intelligence to improve learning in school failed to produce the expected results (Protzko, 2015 (Protzko, , 2016Protzko & Colom, ...
[117]
So is it nature not nurture after all? | Science - The Guardian
Sep 29, 2018 · In a new book likely to rekindle fierce controversy, psychologist Robert Plomin argues that genes largely shape our personalities and that the latest science ...
[118]
Genomic analysis of family data reveals additional genetic effects on ...
However, molecular genetic studies using unrelated individuals typically report a heritability estimate of around 30% for intelligence and between 0 and 15% for ...<|separator|>
[119]
Marxism and Science: The Legacy of Richard Lewontin
Dec 29, 2021 · Beyond debunking the bad science behind biological determinism, Not in Our Genes used a Marxist approach to explain the ideological basis for ...
[120]
E.O. Wilson's Sociobiology and the Marxist Response: A Critique of ...
E.O. Wilson defined Sociobiology as "the extension of population biology and evolutionary theory to social organization" (Wilson 2000).
[121]
Defending Stephen Jay Gould's Crusade against Biological ...
Jun 24, 2011 · Biological determinism is a blight on science. It implies that the way things are is the way they must be. We have less choice in how we live ...Missing: objections | Show results with:objections
[122]
Stephen Jay Gould's Critique of Progress - Monthly Review
He sought to show that biology is a historical science that cannot be reduced to a set of mechanical, deterministic laws. However, Gould also focused on ...
[123]
A BIOLOGICAL UNDERSTANDING OF HUMAN NATURE - Edge.org
Sep 9, 2002 · PINKER: Most intellectuals today have a phobia of any explanation of the mind that invokes genetics. They're afraid of four things. First there ...<|control11|><|separator|>
[124]
The Blank Slate by Steven Pinker - Commentary Magazine
Dec 1, 2002 · The Blank Slate: The Modern Denial of Human Nature by Steven Pinker. Viking. 528 pp. $27.95. Why is the idea of an inborn human nature so controversial?Missing: heredity | Show results with:heredity
[125]
John Maynard Smith - Humanists UK
And it was not just that he was scientifically wrong, but that the scientific error emerged directly from Marxism. He was being supported by the Communist Party ...<|separator|>
[126]
Biological Determinism as an Ideological Weapon
A remarkably explicit recent statement of this assertion is that of Richard Herrnstein, a psychologist who is one of the leading ideologues of “natural ...
[127]
The Ideological Subversion of Biology | Skeptical Inquirer
They include a disdain for biological determinism; a belief that things that can be learned, such as language, cannot at the same time involve capacities ...
[128]
"biological Determinism" as an Ideological Buzz-word
The term "biological determinism" has become a buzzword in the IQ controversy for those who adhere to what Sandra Scarr once called "naive environmentalism" -- ...
[129]
A Critical Assessment of the Equal-Environment Assumption of the ...
The CTM rests on the equal-environment assumption (EEA) that identical and fraternal twin pairs experience equivalent trait-relevant environmental exposures.
[130]
[PDF] The Equal Environment Assumption in Twin Studies of Political Traits
Recent criticisms of the EEA in political science (Beckwith & Morris 2008;. Charney 2008), as well as responses to those criticisms (Alford, Funk, & Hibbing ...
[131]
An Investigation of a Measure of Twins' Equal Environments - PMC
Violations of this assumption could lead to biased parameter estimates in twin models. A variety of methods and measures have been used to test this assumption.
[132]
What can we learn from twin studies? A comprehensive evaluation ...
Twin studies are a major source of information about genetic effects on behavior, but they depend on a controversial assumption known as the equal environments ...
[133]
The dubious precision and utility of heritability estimates
Sep 13, 2022 · We offer additional arguments to further bolster their claims, highlighting methodological issues in heritability coefficients' derivation, ...
[134]
Three Legs of the Missing Heritability Problem - PMC
The so-called 'missing heritability problem' is often characterized by behavior geneticists as a numerical discrepancy between alternative kinds of ...
[135]
The heritability of self-control: A meta-analysis - ScienceDirect.com
Twin studies show that self-control is heritable, but estimates range between 0% and 90%, making it difficult to draw firm conclusions.
[136]
Rethinking heritability - F1000Research
It can now be seen that both the behavioral genetic and the standard biological concept of heritability are based on the false view that only genes are ...
[137]
(PDF) Heritability Studies: Methodological Flaws, Invalidated ...
Aug 6, 2025 · The chapter argues that heritability studies are futile for two reasons: (1) heritability studies suffer from serious methodological flaws.
[138]
Behavioral Genetics on the Brink: A Review of Eric Turkheimer's ...
Apr 23, 2025 · As the behavioral genetic paradigm unravels, the social and behavioral sciences should begin working on a new post-behavioral genetics ...
[139]
Gene discovery and polygenic prediction from a genome-wide ...
Jul 23, 2018 · We found that a polygenic score derived from our results explains around 11% of the variance in educational attainment. We also report ...
[140]
Racial-group differences in IQ in the Minnesota Transracial Adoption ...
In this article, we respond to criticisms by Levin and Lynn of our 1992 follow-up study of IQ and achievement in a simple of transracial adoptees and their ...
[141]
Long-term cognitive and academic effects of early childhood ...
Early childhood education is found to produce persistent effects on achievement and academic success, but not on IQ (with some exceptions).
[142]
The long-term impact of the Head Start program - Brookings Institution
Aug 19, 2016 · We find that the likelihood of pursuing some higher education is increased between 4 and 12 percentage points by Head Start.v We further ...
[143]
Sir Francis Galton and the birth of eugenics - PubMed
He constructed his own theory of inheritance in which nature and not nurture played the leading role. He actively began to promote eugenics and soon gained ...Missing: determinism | Show results with:determinism
[144]
The Supreme Court Ruling That Led To 70000 Forced Sterilizations
Mar 7, 2016 · Indiana adopted a eugenic sterilization law, America's first in 1907. We were writing the eugenics sterilization statutes that decided who ...
[145]
The Biological State: Nazi Racial Hygiene, 1933–1939
... eugenics determined the course of state policy. Hitler's regime touted the “Nordic race” as its eugenic ideal and attempted to mold Germany into a cohesive ...
[146]
Euthanasia Program and Aktion T4 - Holocaust Encyclopedia
Oct 7, 2020 · The Nazi Euthanasia Program, codenamed Aktion "T4," was the systematic murder of institutionalized people with disabilities.
[147]
The high heritability of educational achievement reflects many ...
No policy implications necessarily follow from finding that genetics permeates educational achievement, because policy depends on values and knowledge.
[148]
Education policy and the heritability of educational attainment
The broad heritability of educational attainment has increased substantially (67-74%), and the environmental impact of family background has correspondingly ...
[149]
[PDF] Genetics and Crime: Integrating New Genomic Discoveries Into ...
We derived the hypothesis that polygenic influences on educational attainment predict criminal offending by integrating genetic discoveries about educational ...
[150]
Genetics and education – What's the message?
Nov 10, 2017 · It is possible for the environment to improve everyone's intelligence, even while the differences between them are for mainly genetic reasons.
[151]
Behavioral Genetics in Criminal and Civil Courts - PMC - NIH
Most behavioral traits are highly heritable, with genetics accounting for 30–50% of the variance in transmission of personality traits, and from 30% to over 70 ...
[152]
The genetics of violent behavior - The Jackson Laboratory
Dec 7, 2015 · According to a meta-analysis on data from 24 genetically informative studies, up to 50% of the total variance in aggressive behavior is explained by genetic ...<|control11|><|separator|>
[153]
Genetics and Crime: Integrating New Genomic Discoveries Into ...
Findings reported here demonstrate how molecular-genetic discoveries can be incorporated into established theories of antisocial behavior.
[154]
Can genomic research make a useful contribution to social policy?
Nov 23, 2022 · The GO Science report explored potential future contributions of genomic research to policy focused on employment, sport, criminal justice and synthetic ...
[155]
Ethical, Legal, Social, and Policy Implications of Behavioral Genetics
The policy implications of a genetic basis for behaviors are widespread and extend beyond the clinic to the socially important realms of education, criminal ...
[156]
Ethical issues in the use of genetic predictions of aggressive ...
May 12, 2025 · Background: The use of genetic predictions of aggressive behavior in the criminal justice system remains a subject of ongoing debate.Missing: heritability | Show results with:heritability
[157]
Behavior genetics and the prospect of “personalized social policy”
The analysis suggests that behavior genetics could dramatically impact social policy, not by sowing fatalism about change, but by offering specific, practical ...<|separator|>
[158]
Genetic fatalism and social policy: the implications of behavior ... - NIH
Recent advances in molecular genetics methods have provided new means of determining the genetic bases of human behavioral traits.
[159]
Behavioral genetics in the 21st century: Current Biology - Cell Press
Mar 14, 2022 · Harden's view on the extent to which genetically informed social science is going to change anyone's mind about social policy is optimistic, ...
[160]
The next 10 years of behavioural genomic research - Plomin - 2022
Nov 4, 2022 · Genetic support comes from twin studies which report that diagnosed disorders yield substantial genetic ... A review of twin and family studies.
[161]
Statistical methods for gene–environment interaction analysis - Miao
Oct 5, 2023 · Future research should strive to develop innovative methodologies that integrate genetic, environmental, and functional genomic data to ...
[162]
Gene-environment interactions within a precision environmental ...
Jul 10, 2024 · We review the state of GEI research, including challenges in measuring environmental factors and advantages of GEI analysis in understanding disease mechanisms.
[163]
Celebrating a Century of Research in Behavioral Genetics
Jan 20, 2023 · The nature of nurture is one of the major directions for research in behavioral genomics, as discussed later. Heritability Increases During ...<|separator|>
[164]
Current Challenges and New Opportunities for Gene-Environment ...
Recently, many new approaches, study designs, and statistical and analytical methods have emerged for studying gene-environment interactions (G×Es) in large- ...