FETAL TESTOSTERONE AND CRIMINALITY: TEST OF EVOLUTIONARY NEUROANDROGENIC THEORY

• Author: Anthony W. Hoskin,Lee Ellis
• Published date: 01 February 2015
• Date: 01 February 2015
• DOI: http://doi.org/10.1111/1745-9125.12056

FETAL TESTOSTERONE AND CRIMINALITY: TEST

OF EVOLUTIONARY NEUROANDROGENIC

THEORY∗

Anthony W. Hoskin1and Lee Ellis2

1Criminology Program, University of Texas of the Permian Basin

2Department of Anthropology and Sociology, University of Malaya

KEYWORDS: 2D:4D digit ratio, prenatal testosterone, sex, crime, delinquency, evolu-

tionary neuroandrogenic theory

Evolutionary neuroandrogenic (ENA) theory asserts that criminality is a crude form

of competitive behavior over resources, status, and mating opportunities. Theoreti-

cally, males have been selected for resource acquisitiveness as a result of female prefer-

ences for mates who are successful at resource provisioning. ENA theory also asserts

that brain exposure to both prenatal and postpubertal androgens (particularly testos-

terone) promotes all forms of competitiveness, including those that victimize others.

The present study was undertaken to test ENA theory by correlating 14 self-reported

measures of offending with a biomarker for fetal testosterone exposure based on the

ratio of the 2nd and 4th digits of the right hand (r2D:4D), in a nonrepresentative sam-

ple of 445. Both Spearman correlations and negative binomial regressions produced

results that largely supported the hypothesized connection between offending and high

prenatal androgen exposure, even when findings were analyzed separately by sex. Also,

offending was significantly associated with r2D:4D for both males and females. Over-

all, this study supports the view that exposing the brain to high levels of testosterone

and other androgens prenatally elevates the probability of offending later in life.

Although the biosocial perspective remains a minority approach to criminology

(Cooper, Walsh, and Ellis, 2010), many biosocial theories have been offered in recent

years (Wright, 2010; Wright and Cullen, 2012). Some are Darwinian in nature, arguing

that various forms of criminality have evolved by natural selection—that is, sexual as-

sault (McKibbin et al., 2008; Thornhill and Palmer, 2000), homicide (Buss, 2006; Daly and

Wilson, 1988), child abuse (Jones, 1996; Lightcap, Kurland, and Burgess, 1982), genocide

(Ghiglieri, 2000), and terrorism (Thayer and Hudson, 2010). Other biosocial theories fo-

cus on neurology or neurochemistry, arguing that one or more brain functioning patterns

of offenders differ on average from what is typical of nonoffenders (DeLisi, 2011; Raine,

1997; Walsh and Beaver, 2009; Yang and Raine, 2009).

∗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.2015.53.issue-1/issuetoc.

Direct correspondence to Anthony W. Hoskin, Criminology Program, University of Texas of the

Permian Basin, 4901 E. University Boulevard, Odessa, TX 79762 (e-mail: hoskin a@utpb.edu).

C2014 American Society of Criminology doi: 10.1111/1745-9125.12056

CRIMINOLOGY Volume 53 Number 1 54–73 2015 54

FETAL TESTOSTERONE AND CRIMINALITY 55

EVOLUTIONARY NEUROANDROGENIC THEORY

A decade ago, a biosocial theory was proposed that contained both evolutionary and

neurological elements (Ellis, 2003, 2005). The theory, called evolutionary neuroandro-

genic (ENA) theory, depicts most criminality as being an expression of crude forms of

competition for resources, status, and mating opportunities. As to why involvement in

crime normally declines as individuals age beyond adolescence and young adulthood,

ENA theory asserts that most people learn quickly that lawful (sophisticated) forms of

competition are usually more effective in acquiring resources, status, and mating op-

portunities (and risk fewer ill consequences) than unlawful (crude) forms. Thus, indi-

viduals who have the greatest difficulties learning and engaging in long-term planning

are those who take the longest time to transition from crude to sophisticated forms of

competition.

At the heart of ENA theory are two propositions: First, males have been favored by

natural selection for being unusually competitive regarding the acquisition of resources,

status, and mating opportunities, which in turn results in their victimizing others more

than females do. Second, androgens (male sex hormones) have evolved in ways that

modify brain functioning to make individuals more competitive and likely to victimize

others.

Beyond these two fundamental assertions, the theory becomes fairly complex in its

explanations for how androgens influence brain functioning to promote competitive

and victimizing behavior. Most of the pertinent variables in this regard are provided in

figure 1 (Ellis, 2005, 2011). This diagram asserts that a wide array of androgen-promoted

neurological, cognitive, learning, and emotional factors interact to impact the probability

of criminal and associated behavior patterns.

According to figure 1, androgens alter three brain functioning patterns during fetal

development. However, these patterns tend not to be fully activated until the onset of

puberty. These three patterns interact with other brain centers affecting foresight and

planning ability (shown in the lower portion of figure 1). According to ENA theory, these

neurological patterns function in ways that shape each individual’s probability of engaging

in delinquency and crime.

The labyrinth of causal connections hypothesized in figure 1 have a limited bearing on

the present study. In fact, only two cells shown in figure 1—those that are shaded—are

directly pertinent to the hypothesis that the current study will test. The shaded cell in the

upper left of the diagram identifies high exposure to perinatal androgens as a key indepen-

dent variable, and the shaded cell in the middle right-hand column specifies criminality

as the dependent variable. In other words, although ENA theory argues that the connec-

tion between prenatal androgens and criminality involves a complex set of intervening

variables, it still unmistakably predicts that exposure to prenatal androgens is central to

elevating the probability of criminal behavior later in life. This hypothesis will be tested

in this study.

MEASURING PRENATAL ANDROGEN EXPOSURE

To test the hypothesis that prenatal androgens promote criminality, one must have

some measure of the presence of androgens during fetal development. Because ENA the-

ory asserts that prenatal and postpubertal androgens both contribute to criminal behavior