PULLING BACK THE CURTAIN ON HERITABILITY STUDIES: BIOSOCIAL CRIMINOLOGY IN THE POSTGENOMIC ERA

• Author: CALLIE H. BURT,RONALD L. SIMONS
• Published date: 01 May 2014
• DOI: http://doi.org/10.1111/1745-9125.12036
• Date: 01 May 2014

PULLING BACK THE CURTAIN ON HERITABILITY

STUDIES: BIOSOCIAL CRIMINOLOGY IN THE

POSTGENOMIC ERA∗

CALLIE H. BURT and RONALD L. SIMONS

School of Criminology and Criminal Justice, Arizona State University

KEYWORDS: behavioral genetics, heritability, twin study, epigenetics, life course,

biosocial

Unfortunately, the nature-versus-nurture debate continues in criminology. Over the

past 5 years, the number of heritability studies in criminology has surged. These studies

invariably report sizeable heritability estimates (∼50 percent) and minimal effects of

the so-called shared environment for crime and related outcomes. Reports of such high

heritabilities for such complex social behaviors are surprising, and findings indicat-

ing negligible shared environmental influences (usually interpreted to include parent-

ing and community factors) seem implausible given extensive criminological research

demonstrating their significance. Importantly, however, the models on which these es-

timates are based have fatal flaws for complex social behaviors such as crime. More-

over, the goal of heritability studies—partitioning the effects of nature and nurture—is

misguided given the bidirectional, interactional relationship among genes, cells, organ-

isms, and environments. This study provides a critique of heritability study methods

and assumptions to illuminate the dubious foundations of heritability estimates and

questions the rationale and utility of partitioning genetic and environmental effects.

After critiquing the major models, we call for an end to heritability studies. We then

present what we perceive to be a more useful biosocial research agenda that is conso-

nant with and informed by recent advances in our understanding of gene function and

developmental plasticity.

Questions about nature versus nurture have been a perennial topic of debate in the

social sciences. Since the 1970s, these questions have been addressed by a field of study

known as behavioral genetics. A major focus of behavioral genetics research has been to

partition the variation in an outcome of interest into a proportion caused by genes (her-

itability) and a proportion caused by the environment (e.g., DiLalla, 2004; Plomin et al.,

2012). These heritability studies (also called quantitative genetics, nonmolecular genetics,

or biometrics) have compared phenotypes (observed characteristics of individuals) within

∗Additional supporting information can be found in the listing for this article in the

Wiley Online Library at http://onlinelibrary.wiley.com/doi/10.1111/crim.2011.52.issue-2/issuetoc.

The authors would like to thank Steven Beach, Kara Hannula, Tanja Link, Travis Pratt, four

anonymous reviewers, and D. Wayne Osgood for valuable comments on earlier drafts of the ar-

ticle. The arguments presented in the article are entirely those of the authors and do not reflect

the views of those who provided feedback. Direct all correspondence to Callie H. Burt, School of

Criminology and Criminal Justice, Arizona State University, 411 N. Central Ave, Ste. 600, Phoenix,

AZ 85004 (e-mail: chburt@asu.edu).

C2014 American Society of Criminology doi: 10.1111/1745-9125.12036

CRIMINOLOGY Volume 52 Number 2 223–262 2014 223

224 BURT & SIMONS

and between families that vary in genetic relationships to estimate the influence of genes.

The general conclusion emerging from heritability studies is that variance in almost ev-

ery human characteristic—including preferences and social behaviors—is shaped signifi-

cantly by genetic influences (Plomin et al., 2012; Turkheimer, 2000). For example, studies

have shown substantial heritability (usually between 40 and 60 percent) of everything

from time spent watching television (Plomin et al., 1990), breastfeeding (Colodro-Conde,

Sanchez-Romera, and Ordonana, 2013), and breakfast eating patterns (Keski-Rahkonen

et al., 2004) to political ideology and party affiliation (Alford, Funk, and Hibbing, 2005)

and delinquency (Wright et al., 2008).

Since 2008, behavioral genetic studies by criminologists investigating the heritability of

criminal behavior and factors associated with crime have been published at a rapid and

seemingly increasing pace. Indeed, every few months new studies estimate the heritabil-

ity of some aspect of criminality, such as self-reported delinquency (e.g., Boisvert et al.,

2012; Wright et al., 2008), arrests (Beaver et al., 2012), self-control (e.g., Beaver et al.,

2008, 2009), and gang membership (Barnes, Boutwell, and Fox, 2012). Notably, behav-

ioral geneticists have been estimating the heritability of antisocial behavior, delinquency,

and criminal convictions for years prior to this recent surge (e.g., Mednick, Gabrielli, and

Hutchings, 1984; Rowe and Osgood, 1984; see Moffitt, 2005, for a review). These studies

have revealed ostensibly that genetic factors explain a substantial portion—between 30

and 90 percent of the variance—of every examined crime-related phenotype with shared

environmental factors playing a minimal role (often reported to be 0 percent).

We are surprised that these somewhat astonishing findings reported in recent studies,

such as the reports of more than 50 percent heritability for such complex social behav-

iors as crime and victimization, have not generated more critical attention in criminol-

ogy. We also are perplexed by the lack of response to the heritability study finding that

so-called shared environmental factors play a minor role in explaining variation in crime-

related phenotypes (e.g., Barnes, Boutwell, and Fox, 2012; Beaver et al., 2008; Beaver,

Ferguson, and Lynn-Whaley, 2010; Boisvert, Wright, et al., 2013). Indeed, the conclu-

sion from many of these heritability studies that little—if any—of the variance in criminal

behavior is due to shared environments, often interpreted to include parenting and com-

munity factors, contradicts a wealth of research conducted during the past century as well

as the major theories of crime. As the renowned psychiatrist and behavioral genetics prac-

titioner Michael Rutter (2006: 11) noted, “[The] sweeping assertions on the irrelevance of

the family environment are not supported by research evidence. It is quite striking that be-

havioral genetics reviews usually totally ignore the findings on environmental influences.

It is almost as if research by non-geneticists is irrelevant.”

The lack of critical attention to heritability studies in criminology is even more conspic-

uous given their known limitations. Since at least the early 1930s, scholars—including

prominent geneticists, neuroscientists, and molecular biologists—have been warning

about the fallibility of heritability studies in human populations, especially for complex so-

cial behaviors such as crime (e.g., Joseph, 2004; Kamin, 1974; Lewontin, Rose, and Kamin,

1984; Wahlsten, 1990; Wilson, 1934). As we discuss in this article, these methodological

problems are not merely a sampling or measurement issue that can be corrected with var-

ious model adjustments but are inherent to the method itself. Remarkably, as we discuss,

many of the recent criminology studies have failed to mention crucial assumptions and

technical limitations, and even fewer have discussed the implications of their violation,

especially for assumptions whose violations bias toward heritability.

PULLING BACK THE CURTAIN ON HERITABILITY STUDIES 225

It is not merely the techniques of heritability studies that are suspect, but also the ba-

sic conceptual framework of heritability studies is unsound (e.g., Charney, 2008; Crusio,

2012; Turkheimer, 2011). Heritability studies rest on a model of gene function that views

genetic effects as independent and separable from the environmental context in which

they operate. Genes, however, do not work this way. Genes are not a self-activating

code that can be understood apart from environmental inputs but are only one part of an

interactive, developmental biopsychosocial system. As we will discuss, genes and the en-

vironment are not separate analytical entities, and thus, it is biologically nonsensical to

attempt to partition genetic from environmental influences on phenotypes (e.g., Gottlieb,

2001; Greenberg, 2011).

Although the problems of quantitative genetic methods have been discussed elsewhere

(see, e.g., Charney, 2008, 2012; Joseph, 2004, 2006; Lewontin, Rose, and Kamin, 1984;

Rutter, 2006), and in criminology several decades ago or more (e.g., Walters and White,

1989), as yet there has been no critical response to the recent profusion of heritability

studies in criminology. Given the significant advances in our understanding of gene func-

tion and the profound theoretical and policy implications of this work, such a response is

sorely needed. It is our objective in this article to provide such a response. Notably, most

of the arguments in this article are not original but are those of prominent scientists, many

of whom we cite, whose criticisms have been largely unheeded by the criminological com-

munity in recent years. We hope to renew a dialogue in criminology about heritability

studies and stimulate what we view as a much-needed debate about the utility of heri-

tability studies for crime and related phenotypes.

The objectives of this article are twofold. First, we critique heritability study methods

and assumptions so that the criminological community can be more informed consumers

of these findings. Our critique is grounded in both methodological and conceptual issues.

Regarding the methodological critique, we argue that heritability studies are seriously

flawed and, thus, do not provide useful estimates of genetic influences on criminal pheno-

types. As we will show, these technical flaws have the effect of biasing estimates toward

inflating heritability and underestimating shared environmental effects. Second, we ar-

gue that, methodological problems aside, partitioning individual differences into genetic

versus environmental influences is a misguided endeavor in the first place. Drawing on

a variety of sources, including the arguments of prominent behavioral geneticists (e.g.,

Rutter, 2006; Turkheimer, 2011), we call for an end to heritability studies in criminology

and recognition of the problematic nature of existing heritability estimates for criminal

phenotypes.

To be clear at the outset, it is not the position of this article that genes do not con-

tribute to individual differences in behavior. Criminal behavior, like all other behavior,

results from a combination of factors, including environmental and genetic ones. Any

claim to the contrary is patently false. We do not wish to move the field toward extreme

cultural or social determinism. Instead, we attempt to tackle these issues and put them

in a new perspective, not by denying the role of genes or other biological factors but by

recognizing the complexity of the biopsychosocial system. Heritability studies do not re-

solve the outworn nature-versus-nurture debate; they promote it. Successfully leveraging

the advances of the genomic era in the new era of postgenomics requires that we move

beyond heritability, transcending the outdated question of how much significance to at-

tribute to genetics versus the environment in the development of particular behaviors and

traits (Lickliter, 2009).