This is a paper I wrote in my 2nd year of Psychology degree on genetic inheritability of crime. It is hoped that this article can help others in their academic endeavors. As always, if you require the reference list, please get in touch, I'll be happy to provide you with the full bibliography.
Critically
evaluate the statement that criminal behaviour is genetically transmitted
Theories pertaining to the genetic
inheritability of crime are primarily concerned with a genetic physiological
abnormality that can be attributed to the cause of criminality. Such theories employ
methodologies that either examine the genealogy of the criminal i.e. twin,
family & adoption studies or, examine the gene-environment interaction to
elucidate the possible causes of criminal behaviour (Joseph, 2001). The
subsequent article aims to expound genetic theories of crime and their
worthiness, whilst also exploring alternatives in light of the nature/nurture
debate in an attempt to gain a holistic understanding of this multifaceted
issue.
Twin studies
rely on the basic premise of comparing concordance rates of criminality between
monozygotic (MZ) twins and dizygotic (DZ) twins. Since MZ twins develop from a
single egg and are ‘identical’ in their genetic make-up, a greater concordance
rate in MZ twins purports a noteworthy genetic influence on criminal behaviour.
After studying concordance rates in 3500 Danish twin pairs, Mednick and
Christiansen (1977) observed a 35% concordance rate in MZ twins compared to
only 13% in DZ twins. Furthermore, a meta-analysis performed on 12 twin studies
found 50% of the variance in measures of criminal anti-social behaviour was
recognised as ‘genetically influenced’ (Mason & Frick, 1994).
Although
the aforementioned evidences suggest a genetic inheritability of crime, there
are certain shortcomings that need to be addressed. Twin studies commonly
assume the experiences and environmental stimuli twins are exposed to are
alike. However, Dalgaard and Kringlen (1976) contend that the greater
concordance rate observed in MZ twins can be attributed to their shared
environmental experiences. MZ twins are frequently raised via the same parental
techniques/environment and Carey (1992) notes, for this reason, MZ twins
imitate one another more than DZ twins. Thus, one MZ twin is a facsimile of
another in almost every aspect, leading to an overestimation of inheritability
in crime
Another
methodological approach in studying genetics and crime involves the examination
of intergenerational criminality in family studies. If crime is genetically
bound, one expects a significant concordance rate between criminal parents and
criminal offspring. Osborn and West (1979) studied the sons of criminal and
non-criminal fathers. It was found that 40% of the sons that had committed
felonies had criminal fathers compared to only 13% of sons with non-criminal
fathers. Evidently, the genealogy of the individual is influential in whether
he becomes a criminal or not. However, Ainsworth (2000) notes as the majority
(60%) of sons with criminal fathers abstained from criminality; there must be
other non-genetic (nurture) features.
Theoretically,
adoption studies adequately separate genetic from environmental influences in
that it separates the child from the biological parents. In a study conducted
by Tehrani and Mednick (2000), adopted individuals who were born to
incarcerated female offenders, possessed significantly greater criminal
convictions compared to a control group. These particular findings suggest the
genes of the individual outweighed the environmental influences in determining
whether he/she would turn out to be a criminal. However, the notion that
criminality is entirely dependent on nature is rebutted by Cadoret, Cain and
Crowe (1983). Cadoret et al. collated statistics
from three adoption studies to observe gene-environment interaction in
adolescent delinquent behaviors. Results suggested antisocial behavior
drastically increased when an adoptee possesses both a genetic factor and an
adverse environmental factor i.e. deprivation. The increase observed due to
both influences is significantly greater than the increase from either factor
alone. This suggests that there is an interaction between ‘criminal genes’ and
adverse environments that can foster and facilitate crime.
Although research
on twin, family and adoption studies appears to be irrefutable and conclusive
in their findings, many commentators have revealed the fallibility of such
methodologies. Kessler and Moos (1970) assert the nature of these studies
seldom provide verification for the supposition crime is genetically bound,
since it does not illuminate what is inherited and how this ‘criminal’
inherited aspect functions and is transmitted. In contrast to this, chromosomal
theories do explain crime in terms of
what is inherited and how it affects criminality.
Fundamentally,
females possess two X chromosomes and males possess an X and a Y chromosome. In
Klinefelter’s syndrome however, males are born with an additional Y chromosome
which has been implicated in aggression. Since males with Klinefelter’s
syndrome possess an added Y chromosome, hyper-aggressive and hyper-masculine
characteristics tend to dominate the personalities of such individuals. The XYY
chromosomal configuration has been found to be particularly apparent in prison
populations (Price, Strong, Whatmore & McClemont, 1966).
Again, the
genetic make-up of an individual is seemingly interwoven in criminality. Though,
this theory lacks explanatory power as Epps (1996) asserts those males with XYY
chromosomes are particularly engaged in non-violent crimes as opposed to
violent crimes. Moreover, it is curtailed in that it is inept in explaining why
and how women are violent or commit crimes.
Certain
theories also suggest there are physical (constitutional) differences between criminals
and non-criminals. Through empirical observations, Lombroso (1876) concluded
that certain individuals are ‘born criminals’ with physical defects i.e.
receding chins who have inherited atavistic (primal) traits. This notion was
then furthered by Sheldon who in 1949 formulated the somatotype hypothesis which states that delinquency is associated a
mesomorphic (athletic/muscular) body type.
The
concept of an archetypal physique of a criminal has been disputed and dismissed
by Goring (1913).In summarising his findings, Goring declares that there are no
significant physiological differences between criminals and non-criminals.
Rather, greater physique variability was found in a normal population than a
criminal population.
Due to the
shortcomings of genetic explanations, it is essential to also examine
psycho-social models to provide a holistic understanding. Eysenck (1996)
implicates personality in crime via the use of the PEN (psychoticism,
extraversion and neuroticism) model. Eysenck notes all individuals possess
these traits to a varying extent. However, criminals, especially violent
criminals, possess excessive pathological amounts of all three traits which
eventually lead to criminal behaviour.
Personality
disorders have also been implicated in crime. According to the DSM IV TR
(2000), Antisocial Personality Disorder (ASPD) is characterised by violation
and disregard of others rights that starts in childhood. Morley and Hall (2003)
note ASPD has been found to be associated with increased criminality and
delinquency.
The social
models explain crime in terms of learning and reinforcement. Bandura and
Walters (1963) illustrated how behaviour can be learned via mere imitation in
one of psychology’s seminal experiments. Children imitated actors or cartoons
physically striking bobo-dolls on a television screen. This has wider
implications in that parenting, or the lack of it, can be imperative in
determining whether an individual turns to criminality or not. The role of
parenting and attachment have also been implicated in crime via the works of
John Bowlby and the maternal deprivation hypothesis. Bowlby (1944) studied 44
juvenile theives in an institution assessing the offenders’ childhood bond with
their respective primary caregivers. He concluded, more than half of the
delinquents had been separated for at least 6 months prior to the age of 5.
Moreover, 32% of the delinquents exhibited ‘affectionless psychopathy’ which is
directly associated with the lack of a monotropic childhood bond. These
conclusions further elucidate the role of an individual’s childhood in
determining criminality.
Family
disunity, childhood abuse, peers, media and drug use are all social factors
Lykken (1995) notes as influential variables. However, when deliberating social
theories of crime it is difficult not to transcend the realm of psychology and
delve deep into plain sociological conjecture (e.g. with poverty) that at its
essence looks for no real-life conclusion. In a strict psychological sense,
where the focus is on the individual, it is more than likely that crime is a
concoction of a plethora of factors that encapsulate both nature and nurture.
In this respect, crime can be seen as polygenic where the diathesis stress
model (Gross, 2010) accounts first, for a genetic predisposition and second, an
environmental trigger that intensifies the natural propensity to commit a
crime.
Foyzul Rahman, 30/01/2013.
Recommended citation: Rahman, F. (2012). Crime & Genetics. http://knowledge-fozrahman.blogspot.com/2013/01/crime-and-genetics.html
Foyzul Rahman, 30/01/2013.
Recommended citation: Rahman, F. (2012). Crime & Genetics. http://knowledge-fozrahman.blogspot.com/2013/01/crime-and-genetics.html
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