Article

Three Laws of Behavior Genetics and What They Mean

Authors:
To read the full-text of this research, you can request a copy directly from the author.

Abstract

Behavior genetics has demonstrated that genetic variance is an important component of variation for all behavioral outcomes, but variation among families is not. These results have led some critics of behavior genetics to conclude that heritability is so ubiquitous as to have few consequences for scientific understanding of development, while some behavior genetic partisans have concluded that family environment is not an important cause of developmental outcomes. Both views are incorrect. Genotype is in fact a more systematic source of variability than environment, but for reasons that are methodological rather than substantive. Development is fundamentally nonlinear, interactive, and difficult to control experimentally. Twin studies offer a useful methodological shortcut, but do not show that genes are more fundamental than environments.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the author.

... Twin and family studies are remarkably potent. Family members are highly correlated for practically all phenotypes, and identical twins are correlated at a level observed in no other domain of human science (Turkheimer, 2000). The robustness of familial resemblance makes family relations a powerful tool for the social scientist faced with understanding complex networks of causation under conditions in which randomized experimentation is often impossible (Turkheimer & Harden, 2014). ...
... What advice do twin studies offer to the college administrator who wants to help with alcohol problems on campus? Alcohol use, like every other behavioral phenotype that has ever been studied, is heritable in the sense of twin and family studies (Turkheimer, 2000), but what is a college freshman supposed to conclude from that? Most people do not have an identical twin to serve as a predictor. ...
... Most importantly, the assertion that a behavioral phenotype is genetically influenced is vacuous. All behavioral phenotypes are genetically influenced, as the senior author of this essay documented long ago (Turkheimer, 2000). Moreover, to the extent it was ever necessary to martial empirical evidence in support of genetic influence on behavioral traits, that evidence was widely available from twin and adoption studies 50 years ago. ...
Article
The research program Spit For Science was launched at Virginia Commonwealth University (VCU) in 2011. Since then, more than 10,000 freshmen have been enrolled in the program, filling out extensive questionnaires about their drinking, general substance use, and related behaviors, and also contributing saliva for genotyping. The goals of the program, as initially stated by the investigators, were to find the genes underlying the heritability of alcohol use and related behaviors, and in addition to put genetic knowledge to work in ways that might aid university administrators and mental health professionals in the prevention and treatment of substance abuse. We review every empirical paper involving genetic data that has emerged from the program, and reach a surprising conclusion: the study has never identified a single genetic effect of more than trivial magnitude. Although the quantitative results of the studies were reported transparently, the theoretical ramifications of the negligible results have never been acknowledged. To the contrary, most of the papers ignore the tiny effects, reaching optimistic conclusions about the prospects for future genetic explanations of alcohol use. We explore the implications of these results for the broader prospects of applied psychiatric genetics.
... Personality traits are renowned for being very little influenced by shared environments, such as family, school, or socioeconomic status (Marees et al., 2021). The 2nd law of behavioral genetics states that additive genetics always explain a greater share of variance than the sibling shared environment (Turkheimer, 2000). A large inter-generational study on 7 cohorts reported the largest effect of SES on the Big Five to be only d = 0.15 on the trait openness (Sutin et al., 2017). ...
... Research on the home literacy environment (HLE) has assumed a causal effect of parental nurturing based on significant associations between the reading environment parents provide and children's reading abilities (e.g., S en echal & Lefevre, 2002;S en echal, 2006;S en echal & Lefevre, 2014). However, parents do not only provide the reading environment but also the genes that influence their child's development (Turkheimer, 2000). Thus, parents can indirectly affect children's reading not only by passing on a genetic predisposition for reading (dis)ability to them but also by promoting literacy activities at home or furnishing their home with books. ...
Article
Full-text available
Background Numerous studies have investigated the associations between the home literacy environment (HLE) and children's word reading skills. However, these associations may partly reflect shared genetic factors since parents provide both the reading environment and their child's genetic predisposition to reading. Hence, the relationship between the HLE and children's reading is genetically confounded. To address this, parents' reading abilities have been suggested as a covariate, serving as a proxy for genetic transmission. The few studies that have incorporated this covariate control have made no distinction between the HLE reported by each parent or controlled for different skills in parents and children. We predicted children's reading development over time by the reading abilities of both parents as covariates and both parents' self‐reported HLE as predictors. Methods We analyzed data from 242 unrelated children, 193 mothers, and 144 fathers. Children's word reading was assessed in Grades 1 and 3, and parents' word reading was assessed on a single occasion. Predictors of children's reading development included literacy resources and shared reading activities. Results Children's reading in Grade 3 was predicted by mothers' engagement in reading activities and by literacy resources at home, even after controlling for the genetic proxy of parental reading abilities. The longitudinal rate of change from Grades 1 to 3 was not associated with the HLE or parental reading. Conclusions Our finding that parental reading skills predicted children's word reading beyond children's initial word reading underscores the importance of considering genetic confounding in research on the home environment. Beyond parental reading abilities, children's skills were predicted by literacy resources in the home and by how often mothers engage in reading activities with their children. This suggests true environmental effects.
... purely environmentalist) explanations of human development and performance are incapable of capturing the diversity and scope of research results in this area. Indeed, the 'First Law of Behavioral Genetics', that "all traits are heritable", provides devastating evidence against an environmentalist position [21]. All the same, it is clear there is no 'one size fits all' framework that will capture the variability of skill acquisition in all sporting contexts (as reflected in recent movements to frame athlete development as dynamic and 'nonlinear'). ...
Article
Full-text available
Many areas of mainstream psychology have embraced the notions that understanding human behaviour can be improved by integrating developments from evolutionary science; however, evolutionary principles have not been as widely applied among sport researchers or practitioners, especially those examining athlete development and the psychology of competition and performance. In this paper, we discuss the distinction between ultimate and proximate explanations of psychological outcomes, and the relevance of this distinction for exploring issues related to skill acquisition and athlete development. We use three examples—deliberate practice, early sport play and sustained engagement—to highlight the benefits and challenges of applying evolutionary theories to sport contexts. Embracing our species’ evolutionary history has the potential to inform ongoing debates in athlete development and performance, among other areas of sport science.
... Twin studies have been widely applied to investigate various human behaviors, including: This widespread applicability highlights the notion often referred to as "the first law of behavior genetics": all human behavioral traits likely have some degree of heritability, estimated to be around 50% [18]. ...
Article
Full-text available
This review systematically summarized and discussed the impacts of genetics and geoscience on human behaviors, especially young people, and how human behaviors change the geographic environment. In the review, some basic methodologies of genetic epidemiology have been revisited. It also compared environmental influences with adaptive genetic influences across various adolescent behaviors as examples. Pathways for the occurrence of genetic risks arepresented in this review as well where issues not just in deviant behaviors but also in the health issues mentally and physically. While geographic environment has impacts on the behaviors of young people, human activities are one of the reasons for those changes as well. Summaries and insights exhibited in this review can not only shed light on future research of the impact of various human activity on the geographic environment, but also implies benevolent activities human can take for the environment that consequentially benefit the growth of our adolescents at both cognitive and body level.
... Hence, if MZs are more similar in the outcome of interest compared to DZs, it can be concluded-under certain assumptions-that genetic influences are important for explaining variation in that particular trait. Synthesizing results based on twin designs has led to the formulation of the "[t]hree laws of behavioral genetics" (Turkheimer 2000). First, all human behavioral traits are heritable. ...
Article
Full-text available
Sociological theory and empirical research have found that parents’ socioeconomic status and related resources affect their children’s educational outcomes. Findings from behavior genetics reveal genetic underpinnings of the intergenerational transmission of education, thus altering previous conclusions about purely environmental transmission mechanisms. In recent years, studies in molecular genetics have led to new insights. Genomic data, polygenic scores, and other facets of sociogenomics are increasingly used to advance research in social stratification. Notably, the 2018 discovery of “genetic nurture” suggested that parents’ genes influence children above and beyond the genes they directly transmitted to their children. Such indirect genetic effects can be interpreted as consequences of parental behavior, which is itself influenced by the parents’ genetics and is essential for their children’s environment. Indirect genetic effects fit hand in glove with the sociological literature because they represent environmental transmission mechanisms. For instance, parenting behaviors, which are partly influenced by parents’ genes, shape children’s home environments and possibly their later educational outcomes. However, current findings based on more sophisticated research designs demonstrate that “genetic nurture” effects are actually much smaller than initially assumed and hence call for a reevaluation of common narratives found in the social stratification literature. In this paper, we review recent developments and ongoing research integrating molecular genetics to study educational outcomes, and we discuss their implications for sociological stratification research.
... When the heritability of a trait is high, meaning it's close to 1, it means that most of the variation between individuals can be explained by genetics; when it's low, meaning it's close to zero, most of the variation cannot be attributed to genetics. A trait's high heritability does not imply that a single gene causes it in a clear biological way; rather, it indicates that the trait's total contribution from all direct and indirect causal effects as well as other correlations between distinct DNA variants and the trait are sufficient to be informative [13,14]. ...
Article
Heritability allows comparing the relative contributions of genes and environment to trait variation both within and between populations. Geneticists and plant breeders frequently use heritability as a measure for how is accurate a trial or set of trial. Sewall Wright and Ronald Fisher established the idea of heritability almost a century ago, defining it as an estimable, dimensionless population quantity. Heritability is still essential to the response to selection in evolutionary biology and agriculture, particularly in plant breeding, despite ongoing misconceptions and disputes regarding its usage and application. The importance of heritability in the genomics era is demonstrated by recent reports of significant heritability for gene expression and novel estimation techniques utilizing marker data. Understanding the common misconceptions surrounding the use of heritability is crucial to minimize confusion during selection in plant breeding.
... Single genes or even networks of genes are extremely rarely predictive of human physical disease, let alone psychological outcomes (Carey, 2011). The lack of a main effect for genes with the finding that all psychological outcomes are interactions has been called the 'gloomy prospect' (Turkheimer, 2000). Gens represent a blueprint that require instructions to be implemented, and those instructions come from experience. ...
Chapter
Full-text available
Evolutionary theory can enrich developmental theory but not just any evolutionary theory will do. Evolutionary systems theory is a developmentally friendly evolutionary theory unlike selfish gene theory because it identifies multiple inheritances beyond genes and takes into account the complex dynamism of development. One inheritance is the species-typical evolved nest, or evolved developmental niche, a set of community provisions that evolved to match up with the maturational schedule of the child. Ethogenesis describes the development of ethics across the life span. We can identify two primary moral inheritances that are fostered by the evolved nest. The first is engagement, or flexible relational attunement, which includes capacities for resonance, reciprocity, mutuality, sympathy, and egalitarian relations with face-to-face others. The second comes with the development abstracting capabilities that build on engagement capacities into an inclusive communal imagination. A species-typical nest provides what babies and young children need to develop a full human nature.
... Accordingly, high sexual motivation has greater evolutionary utility for men. Given these observations, paired with the fact that most higher level psychological traits have at least some genetic components (Polderman et al., 2015;Turkheimer, 2000), we find it plausible that there may be biological components to trait sex drive and gender differences therein. This document is copyrighted by the American Psychological Association or one of its allied publishers. ...
Article
Full-text available
Our meta-analysis on gender differences in sex drive found a stronger sex drive in men compared to women (Frankenbach et al., 2022). Conley and Yang (2024) criticized how we interpreted the findings and provided suggestions regarding the origins of these gender differences, an undertaking that we had refrained from doing in our original work. We concur with several important points made by Conley and Yang (2024): (a) women’s sexual experiences are generally more negative than men’s, which could partly explain why men report more sex drive; (b) lack of statistical moderation by some sociocultural variables does not imply that the sex drives of men and women are generally unaffected by the social environment; and (c) gender differences in sexuality are likely smaller than they are often portrayed in research, and that the practical impact of this difference is largely unknown. Still, we reject other assertions made by Conley and Yang (2024): (a) we did not frame our findings in support of the view that gender differences in sex drive are determined by biology, (b) we did not conflate response bias with sociocultural biases more broadly, and (c) we did not fail to incorporate and consider gendered cultural messages about sexuality in our methods and discussion. We make several suggestions about future research on these matters.
... We note the lack of shared environmental effects (C) that we found for creativity and for BPD (in the univariate as well as the bivariate models). A small C is fairly common in many psychological traits 57,58 . A possible explanation is that interactions of C with additive genetic effects are counted as "A" in the classical twin design 59 . ...
Article
Full-text available
Creativity and mental disorders are sometimes seen as intertwined, but research is still unclear on whether, how much, and why. Here we explore the potential role of shared genetic factors behind creativity and symptoms of borderline personality disorder (BPD, characterized by mood swings and randomness of thoughts). Data were collected from 6745 twins (2378 complete pairs) by the Netherlands Twin Register on BPD scores (PAI-BOR questionnaire) and working in a creative profession (proxy for creativity). First, we tested whether there is an association between BPD symptoms and creative professions. Results confirmed that individuals scoring higher on the BPD spectrum are more likely to have a creative profession (Cohen’s d = 0.16). Next, we modeled how much of this association reflects underlying genetic and/or environmental correlations—by using a bivariate classical twin design. We found that creativity and BPD were each influenced by genetic factors (heritability = 0.45 for BPD and 0.67 for creativity) and that these traits are genetically correlated rG = 0.17. Environmental influences were not correlated. This is evidence for a common genetic mechanism between borderline personality scores and creativity which may reflect causal effects and shed light on mechanisms.
... Environmental inequalities in cultural and economic resources and investments would largely explain why children from high-SES families are more likely to succeed in schools than their low-SES peers (Jackson, 2013). At the same time, from behavioural genetics scholarship, it is well established that individual differences in nearly every phenotype of interest to social scientists are heritable to some degree (Polderman et al., 2015;Turkheimer, 2000;Van Hootegem, Rogne, & Lyngstad, 2024). Classical twin studies (Branigan, McCallum, & Freese, 2013;Silventoinen et al., 2020) and novel molecular studies directly measuring the genome (Lee et al., 2018;Okbay et al., 2022) show that educational attainment is no exception, with genetics explaining between 40 % and 16 % of the variance, respectively. ...
Article
Full-text available
This study examines the role of genes and environments in predicting educational outcomes. We test the Scarr-Rowe hypothesis, suggesting that enriched environments enable genetic potential to unfold, and the compensatory advantage hypothesis, proposing that low genetic endowments have less impact on education for children from high socioeconomic status (SES) families. We use a pre-registered design with Netherlands Twin Register data (426 ≤ N individuals ≤ 3,875). We build polygenic indexes (PGIs) for cognitive and noncognitive skills to predict seven educational outcomes from childhood to adulthood across three designs (between-family, within-family, and trio) accounting for different confounding sources, totalling 42 analyses. Cognitive PGIs, noncognitive PGIs, and parental education positively predict educational outcomes. Providing partial support for the compensatory hypothesis, 39/42 PGIxSES interactions are negative, with 7 reaching statistical significance under Romano-Wolf and 3 under the more conservative Bonferroni multiple testing corrections (p-value < 0.007). In contrast, the Scarr-Rowe hypothesis lacks empirical support, with just 2 non-significant and 1 significant (not surviving Romano-Wolf) positive interactions. Overall, we emphasise the need for future replication studies in larger samples. Our findings demonstrate the value of merging social-stratification and behavioral-genetic theories to better understand the intricate interplay between genetic factors and social contexts.
... Theories of literary and cultural tastes in the social sciences, and empirical research that builds on these theories, provide no answer to this question, as they focus exclusively on how social environments (in particular, the family environment and social environments outside the family) shape literary and cultural tastes [1][2][3][4]. Yet, research outside the social sciences indicates that practically all human phenotypes are heritable to some extent, with heritability defined as the degree to which variation in a phenotype in a population is due to genetic variation between individuals in that population [5,6]. Moreover, while reading skills and the propensity to read are heritable [7], we know little about whether, conditional on reading, the taste for different literary genres and formats is also heritable. ...
Article
Full-text available
Social science research argues that differences in individuals’ literary and cultural tastes originate in social environments. Yet, it might be that these differences are partly associated with genetic differences between individuals. To address this possibility, we use nation-scale registry data on library borrowing among Danish twins (N = 67,900) to assess the heritability of literary tastes. We measure literary tastes via borrowing of books of different genres (e.g., crime and biographical novels) and formats (physical, digital, and audio) and decompose the total variance in literary tastes into components attributable to shared genes (heritability), shared environments (social environment shared by siblings), and unique environments (social environments not shared by siblings). We find that genetic differences account for 45–70 percent of the total variance in literary tastes, shared environments account for almost none of the variance, and unique environments account for a moderate share. These results suggest that literary tastes are approximately as heritable as other human phenotypes (e.g., physical traits, cognition, and health). Moreover, heritability is higher for socioeconomically disadvantaged groups than for advantaged groups. Overall, our results suggest that research should consider the role of genetic differences in accounting for individual differences in literary and broader cultural tastes.
... Heritability studies have shown that virtually all human traits are to some extent heritable (Turkheimer, 2000;Polderman et al., 2015). This 'First Law' of behavioural genetics has important implications for how differences and inequalities between individuals perpetuate through generations, a question that motivates studies of intergenerational mobility. ...
... Different theoretical accounts converge on the idea that personality traits and individual differences in these traits can change over time and across age (Caspi & Moffitt, 1993;Geukes et al., 2018;Roberts & Nickel, 2017;Specht et al., 2014). Two indicators of personality development have been considered in most empirical studies and meta-analyses: (1) mean-level changes and (2) rank-order changes (e.g., Bleidorn et al., 2022;Borghuis et al., 2017;Damian et al., 2019;Roberts & DelVecchio, 2000, 2000. Mean-level changes describe the direction and extent of changes in the average level of personality traits. ...
Preprint
Full-text available
Although personality traits are relatively stable compared to other constructs, comprehensive meta-analyses show that the mean-levels and rank-orders of personality traits change throughout the lifespan. In contrast, relatively little is known about whether and how the variance of personality traits develops across the lifespan. Examining changes in personality trait variance is, however, critical to contextualize knowledge on mean-level changes, to identify disruptive life phases, to evaluate the predictive utility of personality traits across age, and to advance personality development theories. The present meta-analysis thus integrated research from 362 longitudinal studies (total N = 344,270) to identify changes in personality trait variance across the lifespan. Across traits, we found a remarkable stability of personality trait variance, indicating that people neither get more different nor more alike across time and age. The only deviations from this pattern were found in childhood, suggesting that the variance of extraversion, neuroticism, and openness decreases in the first years of life (ages 1 to 4) and that the variance of neuroticism increases in late childhood (ages 5 to 13). These findings were robust across various publication, sample, and assessment characteristics. Our results provide novel insights into personality trait development that may spark theoretical advancements by incorporating concrete predictions about stability and change of personality trait variance. Furthermore, the stability of personality trait variance illustrates that mean-level changes in personality traits seem to be independent of variance changes and that personality traits have a similar potential to predict relevant life outcomes across the lifespan.
... So kann sich ein anfängliches Interesse durch Erfolge und Belohnungen in Kombination mit Gewissenhaftigkeit und stabiler Umgebung zu einer Passion entwickeln, aber auch eine anfängliche Angst gepaart mit Impulsivität zu einer sich ausweitenden Prokrastination und gelernter Hilflosigkeit führen. Schwer zu erfassen ist die Rolle von -glücklichen oder unglücklichen -Zufällen, weil ihre Wirkung durch solche Mitkopplungen enorm vervielfacht werden kann (Turkheimer, 2000). Ich selbst kann zwei Lehrbücher nennen, ohne die mein Leben wohl deutlich anders verlaufen wäre. ...
Chapter
Full-text available
Nicht etwa Flipped Teaching oder Virtual Reality, sondern Persönlichkeitsmerkmale, Einstellungen, Verhaltensmuster, aber auch das Umfeld und die persönliche Lage haben den breitesten Einfluss auf den Lernerfolg: Sie entscheiden darüber, welche Gelegenheiten zum Lernen man wahrnimmt oder eben nicht wahrnimmt. Aber viele Muster des Nicht-Lernens sind so selbstverständlich und damit so unsichtbar wie die Luft, die wir atmen. Die Digitalisierung – insbesondere die durch Covid-19 erzwungene Umstellung auf Distanzlehre – öffnet uns die Augen für solche Phänomene. Dieser Beitrag betrachtet sie auf dem Feld der Hochschul- lehre. Er referiert den Stand der Forschung, zeigt praktische Implikationen für das Lehren und Lernen, diskutiert aber auch das Menschenbild des Bildungssystems.
... The findings cited above, pointing to a much more prominent role of nonshared rather than shared environment in the etiology of life satisfaction, are similar to what behavioral genetics research has shown in many areas of personality, health and development. It is in fact such a common result that Turkheimer (2000) summarized the fact that a "substantial portion of the variation in complex human behavioral traits" (p. 160) is unexplained by genetic or shared environmental effects as his third of three "laws of behavior genetics". ...
... If partner similarity arises because of assortative mating, then this will induce cross-partner correlations between factors that are associated with the trait. If the trait is heritablewhich most traits are 21,22 then partners will tend to carry genetic variants with similar effects on the trait. Genetic similarity between partners has been documented for some traits, including height and educational attainment 6,19,[23][24][25] . ...
Article
Full-text available
Assortative mating – the non-random mating of individuals with similar traits – is known to increase trait-specific genetic variance and genetic similarity between relatives. However, empirical evidence is limited for many traits, and the implications hinge on whether assortative mating has started recently or many generations ago. Here we show theoretically and empirically that genetic similarity between relatives can provide evidence on the presence and history of assortative mating. First, we employed path analysis to understand how assortative mating affects genetic similarity between family members across generations, finding that similarity between distant relatives is more affected than close relatives. Next, we correlated polygenic indices of 47,135 co-parents from the Norwegian Mother, Father, and Child Cohort Study (MoBa) and found genetic evidence of assortative mating in nine out of sixteen examined traits. The same traits showed elevated similarity between relatives, especially distant relatives. Six of the nine traits, including educational attainment, showed greater genetic variance among offspring, which is inconsistent with stable assortative mating over many generations. These results suggest an ongoing increase in familial similarity for these traits. The implications of this research extend to genetic methodology and the understanding of social and economic disparities.
Article
Full-text available
Artykuł prezentuje podstawowe założenia (i wyniki badań) genetyki behawioralnej i teorii socjalizacji grupowej, które mają podważać wyjątkową rolę rodziny w procesie wychowania i wskazywać jednocześnie, że funkcję tę pełni tzw. środowisko swoiste (środowisko niewspólne). Kolejnym etapem jest próba krytycznego spojrzenia na zaprezentowane teorie i wskazanie ich kontrowersyjnych elementów. Choć najbardziej radykalne wnioski płynące z wyżej wymienionych teorii budzą słuszne zastrzeżenia, to cenne jest dowartościowanie w procesie socjalizacji środowiska rówieśniczego i próba opisania mechanizmu jego wpływu w ramach spójnej teorii. Jeśli środowisko rówieśnicze rzeczywiście odgrywa tak ważną rolę w procesie socjalizacji, to rodzi się pytanie, w jakich warunkach może stać się istotnym pozytywnym elementem formacji religijnej i duchowej. Druga praktyczna i pastoralna część artykułu jest próbą odpowiedzi na to pytanie. Zostaje ona poprzedzona krótką refleksją dotyczącą relacyjnej natury Kościoła. W oparciu o własne doświadczenia autor zaproponował analizę kilku konkretnych przypadków (casy study), poprzez które można przedstawić mechanizmy wpływu grupy rówieśniczej na kształt formacji religijnej. Odwołanie do założeń metodyki harcerskiej w formie, w jakiej jest ona stosowana w Skautach Europy, ma charakter uniwersalny, wynika bowiem z naturalnych potrzeb nastolatków i mechanizmów rozwojowych, które wyraźniej ujawniają się dzięki zastosowaniu metodyki harcerskiej.
Article
The goal of psychological science is to discover truths about human nature, and the typical form of empirical insights is a simple statement of the form x relates to y. We suggest that such “one-liners” imply much larger x- y relationships than those we typically study. Given the multitude of factors that compete and interact to influence any human outcome, small effect sizes should not surprise us. And yet they do—as evidenced by the persistent and systematic underpowering of research studies in psychological science. We suggest an explanation. Effect size magnification is the tendency to exaggerate the importance of the variable under investigation because of the momentary neglect of others. Although problematic, this attentional focus serves a purpose akin to that of the eye’s fovea. We see a particular x-y relationship with greater acuity when it is the center of our attention. Debiasing remedies are not straightforward, but we recommend (a) recalibrating expectations about the effect sizes we study, (b) proactively exploring moderators and boundary conditions, and (c) periodically toggling our focus from the x variable we happen to study to the non- x variables we do not.
Article
This special issue of Developmental Review is in honor of Judith Rich Harris and the important contributions she made to the study of child development. Though she lacked traditional credentials and a university position, her work forced professional scholars to reconsider a foundational tenet in psychology. Contrary to both evidence and intuition, Harris argued that parents had no lasting influence on the personalities, preferences, and temperaments of their children. Her ideas were met with incredulity, and it would take time before reflexive doubt gave way to more careful consideration. In the decades following the publication of her most well-known book, The Nurture Assumption, her influence has spread well beyond the boundaries of her own field, developmental psychology. Contributors to this volume include criminologists, social psychologists, and behavior geneticists alike. The special issue represents an exciting opportunity to reflect on a remarkable psychologist and the legacy that endures from her unlikely scholarly career.
Preprint
Full-text available
Philosophers and psychologists alike have long debated the etiology of beliefs about human agency. Recently, empirical investigations have shown that lay beliefs about free will and determinism represent stable and important individual differences. Despite a perennial interest in the sources of agentic belief, genetic and environmental influences on such beliefs have never been studied. We administered a battery of items assessing these beliefs to a unique sample of 394 adoptive and biological families with adult offspring to investigate the origins of agentic beliefs and their relationships. We found significant differences between adopted and biological offspring and between the parents of such children, particularly in beliefs about determinism. Biometric modeling revealed especially surprising results: unlike the vast majority of traits studied in family designs, agentic beliefs appear to be weakly or not at all heritable. Since genetic factors might be regarded as typical of the "initial conditions" in philosophical thought experiments about free will and determinism, it is especially ironic that beliefs about free will and determinism may be among the traits least influenced by genetic differences.
Article
Full-text available
The paper presents a polemics with a thesis formulated by J. Harris that group socialization theory is an alternative to family nurture. The thesis, indeed, “annihilates” the nurture category and the existing achievements of education sciences off the scientific discourse. The text focuses on an analysis of consistency of arguments regarding the main aspects of the theory in question, identified at four levels of tensions between: genes and environment, child and adult, family and peer group, and being raised in the family and socialization in peer group. The inconsistencies and overinterpretations, expressed by J. Harris in her “systemic” depreciation of child-rearing, inspired some reflections about the possible roles of nurture viewed in the paradigm of biological and spiritual evolution synthesis.
Article
Full-text available
Objective: Hoarding disorder is a complex condition that significantly impacts individuals' lives, characterized by excessive acquiring, difficulty discarding, clutter, distress, and impairment. This study aimed to examine the extent to which genetics and environment influence difficulty discarding, excessive acquisition, and clutter through the implementation of a classical twin study. Method: This classical twin study, conducted between April and September 2021, enrolled 194 twins (97 pairs) from Isfahan, recruited through the Isfahan Twins Registry (ITR). A total of 194 twins, consisting of 100 monozygotic (MZ) and 94 dizygotic (DZ) twins, participated in this study. Participants aged 16-50 were invited electronically and completed an online consent form and questionnaire. Hoarding symptoms were assessed using the saving inventory-revised. Zygosity was determined using a self-report method based on Song et al.'s questionnaire. To estimate the heritability of hoarding symptoms, the classical univariate twin model was employed. Results: Based on the univariate analysis, the heritability estimates for difficulty discarding and excessive acquisition were found to be 0.43 and 0.52, respectively. However, the results did not provide support for the role of genetics in clutter. Instead, it was indicated that the common environment accounted for 0.54 of the variance in clutter, while the specific environment contributed 0.46 to this symptom. Conclusion: The difficulty discarding and excessive acquisition were found to be moderately heritable. On the other hand, considering the contribution of genetics and environment to clutter, the results raise doubts about the association of clutter with hoarding. The relatively low genetic influence suggests that this trait may overlap with other behaviors rather than hoarding.
Article
Family-based genome-wide association studies (GWASs) are often claimed to provide an unbiased estimate of the average causal effects (or average treatment effects; ATEs) of alleles, on the basis of an analogy between the random transmission of alleles from parents to children and a randomized controlled trial. We show that this claim does not hold in general. Because Mendelian segregation only randomizes alleles among children of heterozygotes, the effects of alleles in the children of homozygotes are not observable. This feature will matter if an allele has different average effects in the children of homozygotes and heterozygotes, as can arise in the presence of gene-by-environment interactions, gene-by-gene interactions, or differences in linkage disequilibrium patterns. At a single locus, family-based GWAS can be thought of as providing an unbiased estimate of the average effect in the children of heterozygotes (i.e., a local average treatment effect; LATE). This interpretation does not extend to polygenic scores (PGSs), however, because different sets of SNPs are heterozygous in each family. Therefore, other than under specific conditions, the within-family regression slope of a PGS cannot be assumed to provide an unbiased estimate of the LATE for any subset or weighted average of families. In practice, the potential biases of a family-based GWAS are likely smaller than those that can arise from confounding in a standard, population-based GWAS, and so family studies remain important for the dissection of genetic contributions to phenotypic variation. Nonetheless, their causal interpretation is less straightforward than has been widely appreciated.
Article
Cet article propose de retracer l’histoire du couple dichotomique de l’inné et de l’acquis, au XXe siècle et en génétique humaine, grâce aux concepts de déterminisme et de prédisposition. Plus spécifiquement, la génétique humaine a évolué d’un déterminisme essentialiste, faisant des facteurs innés les causes ultimes de la nature humaine, vers un déterminisme probabiliste, reconnaissant l’importance des facteurs environnementaux et l’exprimant en termes de prédisposition génétique. Cette évolution épistémologique se comprend grâce à l’histoire des liens entre génétique et eugénisme aux USA au début du XXe siècle, de la génétique médicale en Angleterre dès 1920 et du développement de la biologie moléculaire à partir des années 1950. Ils expliquent la popularité du déterminisme de l’inné. Mais le XXIe siècle voit se développer une nouvelle ère épistémologique, l’ère post-génomique, qui tend à dépasser théoriquement et concrètement l’opposition entre inné et acquis. La génétique humaine ne se veut plus principalement innée-centrée, et nous verrons qu’il est désormais question de prédisposition interactive.
Chapter
This indispensable sourcebook covers conceptual and practical issues in research design in the field of social and personality psychology. Key experts address specific methods and areas of research, contributing to a comprehensive overview of contemporary practice. This updated and expanded second edition offers current commentary on social and personality psychology, reflecting the rapid development of this dynamic area of research over the past decade. With the help of this up-to-date text, both seasoned and beginning social psychologists will be able to explore the various tools and methods available to them in their research as they craft experiments and imagine new methodological possibilities.
Chapter
This indispensable sourcebook covers conceptual and practical issues in research design in the field of social and personality psychology. Key experts address specific methods and areas of research, contributing to a comprehensive overview of contemporary practice. This updated and expanded second edition offers current commentary on social and personality psychology, reflecting the rapid development of this dynamic area of research over the past decade. With the help of this up-to-date text, both seasoned and beginning social psychologists will be able to explore the various tools and methods available to them in their research as they craft experiments and imagine new methodological possibilities.
Chapter
This indispensable sourcebook covers conceptual and practical issues in research design in the field of social and personality psychology. Key experts address specific methods and areas of research, contributing to a comprehensive overview of contemporary practice. This updated and expanded second edition offers current commentary on social and personality psychology, reflecting the rapid development of this dynamic area of research over the past decade. With the help of this up-to-date text, both seasoned and beginning social psychologists will be able to explore the various tools and methods available to them in their research as they craft experiments and imagine new methodological possibilities.
Article
The exponential expansion of consumer genetic testing has led to an accumulation of massive genomic data sets owned by governments and firms. The prospect of leveraging genetic data for enhancing consumers' health, well-being, and satisfaction through improved personalization, segmentation, and targeting is promising. Nonetheless, this potential has not been studied empirically to date, and it is unknown whether and when firms should invest resources into incorporating genetic data into strategies and processes. The authors address this gap in a study of taste preferences, important drivers of food and beverage consumption. Using a large U.K.-based sample, they find that with sample sizes currently available, genetic data are expected to significantly improve prediction of taste preferences above traditionally used metrics such as demographics, behavioral variables, and even past consumption, especially for tastes that are uncommon in the local diet (e.g., spicy, sour), as they are less expressed behaviorally. The authors conclude that genetic data show immense promise for prediction-based applications when other data sources are limited or uninformative. These findings could have significant implications for public health initiatives, potentially aiding development of personalized nutrition plans and dietary interventions.
Thesis
Full-text available
Subjective well-being is an important psychological construct linked to various relevant life outcomes. Diener (1984) proposed the original conceptualization of the term subjective well-being by defining it as a multidimensional construct consisting of three components: life satisfaction, positive affect, and negative affect. Those three components of subjective well-being are considered theoretically diverse and independent constructs that separate in factor analyses and have different patterns of relations with other variables. So, for example, the cognitive component is less determined by the personality traits than the affective component. The positive and negative affect are also theoretically separated constructs, i.e., not just the opposite poles of one affective dimension. Therefore, in order to adequately assess subjective well-being, it is essential to measure all three components. The subjective well-being can be seen as a trait. This is supported by the findings that subjective well-being has a long term stability, as well as the fact that it is a heritable construct significantly determined by personality traits. The term heritability denotes the proportion of genetic variance attributable to phenotypic variance. It is examined within behavioral genetic research, which aims to decompose the total variance of a phenotype into different types of genetic and environmental influences. Meta-analyses show that various measures of subjective well-being are substantially heritable; that is, about 30 - 40 % of individual differences between people in the assessment of subjective well-being can be attributed to differences in their genotype (Bartels, 2015; Nes & Røysamb, 2015; Vukasović et al., 2012). The rest of the variance is attributed to non-shared environmental factors. Subjective well-being is significantly related to personality traits, which are one of its strongest predictors. More specifically, studies show that neuroticism and extraversion are most closely related to measures of subjective well-being. In addition to those two key traits, meta-analyses show that conscientiousness also significantly predicts some measures of subjective well-being, and less strong effects are sometimes found for agreeableness as well (Anglim et al., 2020; Busseri & Erd, 2023; Steel et al., 2008). The relationship between subjective well-being and personality can be explained by their shared etiology , that is, by sharing common genetic and environmental contributions to individual differences. A smaller number of studies examining this etiological connection have shown that subjective well-being and personality share the same genetic contributions to a significant extent. However, the previous studies disagree on whether a portion of the genetic variance in subjective well-being is unrelated to personality or whether their genetic variances are completely overlapping. Studies examining the relations between personality and subjective well-being have mainly operationalized personality within the framework of Big-Five/Five-factor model. The goal of this research is to operationalize personality within the alternative personality model -- HEXACO -- which defines the existence of six basic personality factors. Although it has some similarities with the five-factor models, the HEXACO also has significant differences compared to the five-factor models, and it can be expected that it would show different patterns of association with measures of subjective well-being. So far, no research has been published in the literature that examined the etiological connection between subjective well-being and HEXACO personality traits. The aim of this study is to examine individual differences in subjective well-being from two perspectives - by examining the etiology of these differencese and by examining their relationship to personality traits operationalized through the HEXACO personality model on phenotypic but also on etiological level. We, therefore, aimed to examine: (i) the heritability of the subjective well-being composite score and its three components (life satisfaction, positive affect, negative affect); (ii) the phenotypic relationships of the subjective well-being composite score and its components with HEXACO personality domains and facets; (iii) the etiological relationships of the subjective well-being composite score and its components with HEXACO personality domains and facets; (iv) the etiological relationships of the three components of subjective well-being. The research was conducted using the classic twin study method. Data were collected on a total of 830 individuals, or 412 pairs of twins. Of these, 144 pairs are monozygotic (MZ) twins, and 268 are dizygotic (DZ) twins. The average age of the participants is 22.15 years, with a range of 19 to 28 years. Also, 63% of the total number of participants were female. The cognitive component of subjective well-being is operationalized by the Satisfaction With Life Scale (SWLS; Diener et al., 1985), consisting of five items, which refer to a global assessment of the extent to which we are satisfied with our own life as a whole. The affective component was measured with a shortened version of the Positive and Negative Affect Schedule (PANAS; Watson et al., 1988), consisting of a total of 16 items. The respondents were instructed to rate how they felt in life in general. The Croatian version of the HEXACO-PI-R questionnaire was used to assess personality traits (Babarović & Šverko, 2013; Lee & Ashton, 2018). It is a questionnaire designed to assess six domains and 25 facets of the HEXACO personality model with a total of 100 items. In order to answer the first problem of this research, four univariate behavioural-genetic models were conducted to examine the sources of individual differences in the variance of life satisfaction, positive affect, negative affect, and the composite score of subjective well-being. The results showed that the data for all four measures are best described by the AE model, which defines the existence of additive genetic variance (A) and non-shared environmental influences (E). It was determined that there is a significant degree of heritability of all measures of subjective well-being, as well as the composite result. More precisely, the heritability of life satisfaction is 54 %, positive affect 49 %, negative affect 47 %, while the heritability of the composite score is 58 %. Non-shared environmental effects account for the remainder of the variance. In order to answer the second problem of this research, a series of correlation and regression analyses were conducted. Results showed that six HEXACO personality domains explain between 31 and 52 % of the variance of measures of subjective well-being, and at the facet level between 40 and 63 %, the most for the composite score and the least for life satisfaction. All four measures of subjective well-being have the highest correlation with the extraversion domain, ranging between -.45 for negative affect and .65 for the composite score. Some differential relations of individual components with certain domains and facets were also determined. A higher level of life satisfaction is predicted by higher levels of extraversion, conscientiousness, or more precisely, narrower traits of social self-esteem, liveliness, and diligence. A higher level of negative affect is predicted by lower extraversion, higher emotionality, and lower agreeableness. More specifically, a greater tendency towards unpleasant emotional tendencies is predicted by higher anxiety, lower social self-esteem, lower liveliness, and lower patience. When it comes to positive affect, it is associated with a higher level of extraversion and conscientiousness, that is, with higher levels of lliveliness, social self-esteem, sociability, social boldness, and diligence. The same pattern is found for a high level of subjective well-being in general, as a composite score, with the addition of it being predicted by a low level of anxiety. The etiological association between personality and subjective well-being was examined by conducting bivariate and multivariate modelling. Results showed that genetic effects explain between 54 % and 76 % of the phenotypic covariance between all measures of subjective well-being and personality, and strong genetic correlations were also established between all examined variables. Multivariate Cholesky models showed that all measures of subjective well-being significantly shared genetic variance with personality, somewhat more with narrower facets than with broader personality domains. However, genetic variance unrelated to these dispositional traits was also established. On average, about 30 % of the total genetic variance is specific to measures of subjective well-being. Finally, results showed that life satisfaction has strong genetic correlations with both affective components, while positive and negative affect are moderately correlated at the genetic level. Multivariate analysis showed that the common factor model best explains the etiological connection between the three components. Thus, between 60 and 70 % of the heritability of the three components is determined by the genetic variance on a common latent factor. In comparison, around 30 - 40 % of the genetic variance is specific to each individual component. In conclusion, this research showed that genetic effects significantly contribute to individual differences in subjective well-being, which are shared to a significant extent with personality traits, primarily with extraversion and its narrower facets that are measured within the HEXACO model. Therefore, the same genetic effects that determine our level of extraversion, conscientiousness, or narrower facets of social self-esteem and liveliness contribute to a large extent to our life satisfaction and positive and negative affect. Nevertheless, although biological factors shared with personality play an essential role in defining the variance of all components of subjective well-being, it was also shown that there is a significant part of the genetic variance of these constructs that is not attributable to personality. Therefore, this research indicates that happiness is not only a matter of personality.
Chapter
The author presents a brief background on Galton’s theory of nature vs. nurture. Though this theory has been widely accepted for decades, three assumptions are required for the theory to be valid: unitivity (they add to one), unidimensionality (they are complementary), and universality (the paradigm is universally true). These assumptions have never been formally addressed or validated. Phenylketonuria (PKU) is commonly used as an exemplar of nature vs. nurture to show their interaction. However, on careful examination, this example shows that Galton’s paradigm leaves out the human element of choice. An alternative approach allows a more parsimonious understanding of the human being using the dimensional ontology of Viktor Frankl. It is suggested that the paradigm should include nature, nurture, and the noëtic—the dimension that makes us uniquely human.
Preprint
Full-text available
Humans engage with music for various reasons that range from emotional regulation and relaxation to social bonding. While there are large inter-individual differences in how much humans enjoy music, little is known about the origins of those differences. Here, we disentangled the genetic factors underlying such variation. We collected behavioural data on several facets of music reward sensitivity, music perceptual ability, and general reward sensitivity from a large sample of Swedish twins (N = 9,169). We found that genetic factors substantially explain variance in music reward sensitivity above and beyond genetic influences shared with music perception and general reward sensitivity. Furthermore, multivariate analyses showed that genetic influences on the different facets of music reward sensitivity are partly distinct, uncovering distinct pathways to music enjoyment and different patterns of genetic associations with objectively assessed music perceptual abilities. These results paint a complex picture in which partially distinct sources of genetic variation contribute to different aspects of musical enjoyment and open up new possibilities for using inter-individual differences to gain insights into the biology of a key aspect of human behaviour.
Article
Full-text available
Modern neuroscientific and genetic technologies have provoked intense disagreement between scientists who envision a future in which biogenetic theories will enrich or even replace psychological theories, and others who consider biogenetic theories exaggerated, dehumanizing, and dangerous. Both sides of the debate about the role of genes and brains in the genesis of human behavior have missed an important point: All human behavior that varies among individuals is partially heritable and correlated with measurable aspects of brains, but the very ubiquity of these findings makes them a poor basis for reformulating scientists’ conceptions of human behavior. Materialism requires psychological processes to be physically instantiated, but more crucial for psychology is the occasional empirical discovery of behavioral phenomena that are specific manifestations of low-level biological variables. Heritability and psychobiological association cannot be the basis for establishing whether behavior is genetic or biological, because to do so leads only to the banal tautology that all behavior is ultimately based in the genotype and brain.
Article
Full-text available
Theories in "soft" areas of psychology (e.g., clinical, counseling, social, personality, school, and community) lack the cumulative character of scientific knowledge because they tend neither to be refuted nor corroborated, but instead merely fade away as people lose interest. Even though intrinsic subject matter difficulties (20 are listed) contribute to this, the excessive reliance on significance testing is partly responsible (Ronald A. Fisher). Karl Popper's approach, with modifications, would be prophylactic. Since the null hypothesis is quasi-always false, tables summarizing research in terms of patterns of "significant differences" are little more than complex, causally uninterpretable outcomes of statistical power functions. Multiple paths to estimating numerical point values ("consistency tests") are better, even if approximate with rough tolerances; and lacking this, ranges, orderings, 2nd-order differences, curve peaks and valleys, and function forms should be used. Such methods are usual in developed sciences that seldom report statistical significance. Consistency tests of a conjectural taxometric model yielded 94% success with no false negatives. (3 p ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Full-text available
C. H. Waddington's (1942) notion of canalization has been widely invoked in developmental psychology to conceptualize species-typical regularities in behavioral development as genetically determined. In contrast, a developmental systems view, such as the one described in the present article, sees the genes as only one component in a hierarchy of influences, all of which contribute to canalize behavioral development. A key issue is that genetic activity does not by itself produce finished traits; differentiation occurs as a consequence of events above as well as below the cellular level, necessarily involving factors in addition to genetic influences to canalize behavioral development. In exploring the possible experiential canalization of development, it was found that the mallard duck embryo's contact call plays a canalizing role in species-specific perceptual development (G. Gottlieb; see record 1991-11868-001). Thus, normally occurring experience, in concert with genetic and other activities, can canalize behavioral development. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Full-text available
offers some understandings and opinions that might facilitate further integration of nature- and nurture-based approaches to human behavior goals of behavioral genetics / overcoming barriers to joint nature–nurture investigation / environments: shared and nonshared, familial and extrafamilial / objective and effective environments and genes / genetic mediation of environmental effects and vice versa / political barriers to the acceptance of behavioral genetics (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Full-text available
When genetic similarity is controlled, siblings often appear no more alike than individuals selected at random from the population. Since R. Plomin and D. Daniels' seminal 1987 review, it has become widely accepted that the source of this dissimilarity is a variance component called nonshared environment. The authors review the conceptual foundations of nonshared environment, with emphasis on distinctions between components of environmental variance and causal properties of environmental events and between the effective and objective aspects of the environment. A statistical model of shared and nonshared environmental variables is developed. A quantitative review shows that measured nonshared environmental variables do not account for a substantial portion of the nonshared variability posited by biometric studies of behavior. Other explanations of the preponderance of nonshared environmental variability are suggested.
Article
C. H. Waddington's (1942) notion of canalization has been widely invoked in developmental psychology to conceptualize species-typical regularities in behavioral development as genetically determined. In contrast, a developmental systems view, such as the one described in the present article, sees the genes as only one component in a hierarchy of influences, all of which contribute to canalize behavioral development. A key issue is that genetic activity does not by itself produce finished traits; differentiation occurs as a consequence of events above as well as below the cellular level, necessarily involving factors in addition to genetic influences to canalize behavioral development. In exploring the possible experiential canalization of development, it was found that the mallard duck embryo's contact call plays a canalizing role in species-specific perceptual development (G. Gottlieb; see record 1991-11868-001 ). Thus, normally occurring experience, in concert with genetic and other activities, can canalize behavioral development. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Impugns the population approach to developmental behavior-genetic analysis and offers a different developmental perspective for the practice of developmental behavior genetics (DBG). Issues addressed include original objectives of behavior genetics, mainstream developmental behavior genetics (DBG), and behavioral reaction norms. The author states that some psychologists have misapplied the statistical procedures of population genetics in an attempt to explain development. He posits that developmental understanding or explanation is a multilevel affair involving culture, society, immediate social and physical environments, anatomy, physiology, hormones, cytoplasm, and genes. Hierarchical, multi- level or developmental systems' analysis is considered to be methodologically reductionistic as psychological understanding or explanation of analysis is necessary to explain developmental outcomes. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Comments on an article by G. Gottlieb (see record 1996-10515-001) regarding the validity of behavioral genetics (BG). The authors argue that there is no fundamental disagreement between Gottlieb's theses and the mainstream view of BG. Issues addressed include heritability, reaction range, and hierarchical models from systems theory. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
The author argues that it is what children experience outside the home, in the company of their peers, that matters most. Parents don't socialize children: children socialize children. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Biometric analyses of variability in behavioral phenotypes have demonstrated that genotype plays a significant role in all behavioral development, but the developmental significance of the environment has remained obscure. Behavior genetic analyses typically show the effect of shared family environment to be very small, although considerable variability remains to be explained after genetic factors have been accounted for. Behavior geneticists have suggested, contrary to intuition, that almost all of the important effects of the environment serve to make family members more different from each other. Environmentalists of several persuasions have pointed to the crucial importance of the environment in the initiation and regulation of all developmental processes. In this article, we present a series of simulations to suggest that some of the difficulty of identifying environmental effects in biometric models is methodological. Adding simple dynamic parameters to models of development leads to systems in which environment produces substantial variability that can be detected in the context of a particular genotype, but vanishes when genotype is allowed to vary.
Article
Understanding both typical human development and indivdual differences within the same theoretical framework has been difficult because the 2 orientations arise from different philosophical traditions. It is argued that an evolutionary perspective can unite the study of both species-typical development and individual variation. Research on determininants of development from many perspectives can be understood within an evolutionary framework in which organism and environment combine to produce development. Species-normal genes and environments and indidividual variations in genes and environments both affect personality, social, and intellectual development. These domains are used as examples to integrate theories of normal development and individual differences. Within the usual samples of European, North American, and developed Asian countries, the results of family and twin studies show that environments within the normal species range are crucial to normal development. Given a wide range of environmental opportunities and emotional supports, however, most children in these societies grow up to be individually different based on their individual genotypes. Understanding the ways in which genes and environments work together helps developmentalists to identify children in need of intervention and to tailor interventions to their particular needs.
Article
Modern neuroscientific and genetic technologies have provoked intense disagreement between scientists who envision a future in which biogenetic theories will enrich or even replace psychological theories, and others who consider biogenetic theories exaggerated, dehumanizing, and dangerous. Both sides of the debate about the role of genes and brains in the genesis of human behavior have missed an important point: All human behavior that varies among individuals is partially heritable and correlated with measurable aspects of brains, but the very ubiquity of these findings makes them a poor basis for reformulating scientists' conceptions of human behavior. Materialism requires psychological processes to be physically instantiated, but more crucial for psychology is the occasional empirical discovery of behavioral phenomena that are specific manifestations of low-level biological variables. Heritability and psychobiological association cannot be the basis for establishing whether behavior is genetic or biological, because to do so leads only to the banal tautology that all behavior is ultimately based in the genotype and brain.
  • E Turkheimer
  • H H Goldsmith
  • I I Gottesman
Turkheimer, E., Goldsmith, H.H., & Gottesman, I.I. (1995). Commentary. Human Development, 38, 142-153.