The nature/nurture issue has been a controversy in professional circles for many years. In criminology then, some hold that criminal behavior is socially (nurture) influenced, while others are of the opinion that genetics (nature) play a substantial role. While it is true that the environment in which a person is raised plays an important role in possible criminal tendencies, studies show that the innate nature of a person plays a very prominent role in criminal behavior. In fact, Plomin (1990, p. 108) states that genetic influence on body build and neurologica may affect such areas as mental ability, personality and psychopathology, thus also influencing personality traits that would include criminal tendencies.
Adopted Children and Twins
In order to determine the extent of genetic influence on behavior, as well as psychological disorders, studies have been conducted involving adopted children and twins (Plomin, 1990, p. 109). Prominent studies done on adoptees in Denmark for example suggest that nature does indeed play a significant role, regardless of the circumstances in the adoptive families. Where neither adoptive nor biological parents were criminal, 14% of a group of 2,492 adopted sons had at least one criminal conviction. Where the adoptive parents, but not biological parents of a group of 204 adopted sons are criminal, 15% of these sons have at least one criminal conviction. The most significant finding is the 1226 cases investigated where the biological parents, but not adoptive parents are criminal. Of these sons, 20% has a criminal record, and where both adoptive and biological parents are criminal, 25% has a criminal record.
Harris (1999) cites the case of Amy and Beth, two identical twins, each adopted by a different set of parents. Despite the contrasts between their environments, both Amy and Beth suffer from the same personality problems. Eaves, Eysenck and Martin (1989, p. 20) mention that the prominent similarity of twins is due to their genetic closeness, as well as the fact that they have the same parents. Obviously then it follows that similar personality disorders such as those experienced by Amy and Beth, despite contrasting environments, are due to their genes, which are similar. This substantiates the hypothesis that nature is a prominent component of behavior and behavioral disorders, and would then also be true of criminal behavior.
Harris (1999) makes a case for nurture through citing behavioral genetic studies of twins or siblings. The environment shared by these individuals often affect both in strengthening their genetic propensity towards crime. Twins or siblings growing up in the same home are likely to display the same amount of criminality:
both are or are not criminal. The home environment itself may however not have an influence, but it is true that socialization occurs both inside and away from home. The siblings or twins for example share the same peer group, which can influence them or strengthen their genetic criminal nature. It is significant that the correlation in criminal nature for these twins is higher when they are raised together than when they are raised apart.
Twin studies are however inconclusive, and it is difficult to determine the exact amount of nature and nurture that play a role in criminal tendencies. (Gale Encyclopedia of Psychology, 2001.) While there are definite similarities that correlate more closely than those between fraternal twins, identical twins have also shown differences, even when raised in the same environment. Here it is possible that small differences in genetic make-up dictate that each twin reacts differently to environmental factors, and thus develop differently, although with the same basic genetic make-up.
It is however also true that many twins separated at birth develop startling similarities, which is then ascribed to genetics. Differences in these cases are ascribed to the environment in which each grows up.
Studies of twins in different environments are inconclusive, since the differences are often arbitrary, and not scientifically measured. Thus the environment could have a greater impact than supposed by some studies, where results indicate genetic similarity despite a difference in environment. Thus it is impossible to exactly determine the amount of nature and nurture involved in personality development. It is however possible to determine the various factors responsible for criminal tendencies, which encompass both genetic and environmental elements.
It is however undeniable that the environment influences behavior, criminal or otherwise. Genetic criminal tendencies can for example be exacerbated by the environment in which these persons grow up, or be alleviated by it. On the other hand, genotype plays a role in how an individual reacts to certain environmental factors (Plomin, DeFries and Fulker, 1988, p.253). Thus, in a home environment, perceived affection (or lack thereof) from parents is therefore influenced by genetic make-up (Plomin, DeFries and Fulker, 1988, p. 283).
Harris (1999) refers to socialization to explain the nurture phenomenon. Morality is for example a product of nurture, received from parents at home. Morality, like all other behavior learned from parents and other social institutions, is a learned social behavior. The context in which it is acquired is as important as the genes determining the child's reaction to such learning.
Pinker (2003) favors the view that both nature and nurture play a role in behavior:
Even when a behavior is heritable, an individual's behavior is still a product of development, and thus it has a causal environmental component."
While genetic influence then does play a role in the way in which development occurs, development also occurs by means of imitation. Children are apt to imitate their parents. Thus, if parents behave in a way that suggests criminality to be right, moral and desirable, children are likely to follow. A genetic propensity towards criminality would serve to reinforce this tendency.
Pinker investigates the paradigm of parenting to make a point about genotype. Parents, he points out, can be excellent, as in the case of Amy. However, a child's genetic disposition could bring into the equation elements not foreseen by parents. Thus, individual differences, such as the perception that a child is "difficult," can be ascribed to genetics. Pinker condemns the "blank slate" theory often used in parenting, which holds that children are born like blank slates, on which a parent can impress anything he or she wishes. Elements of humanity such as individual interest and preference are denied by the Blank Slate theory.
So is the true cause of criminality. According to the above, a child's criminal record cannot be blamed on a parent alone or even in some cases at all. It is often due to the individual's specific genetic make-up, which is perhaps exacerbated by social circumstances such as poverty or persons such as undesirable friends.
The Role of Nature
Harris (1999) focuses her study on the validity of heredity in behavior and personality. Nature, as mentioned above, is the foundation of the personality, which is then further shaped by the environment, or nurture. Thus criminal tendencies may be in-born, but an environment free from criminal parents or friends can influence such a person for the better.
Harris also gives heredity the responsibility for problem children born to problem parents. The author cites various personality problems that could also result in criminal behavior. These include a tendency to be active, impulsive, aggressive, and quick to anger. This often leads to the related problem of being bored quickly, not being afraid to get hurt, and emotional insensitivity. This is exacerbated by a muscular build and a slightly lower than average IQ. All of the above are genetically regulated traits, which sparks a certain reaction to external stimuli.
It is clear that the role of nature in criminal tendencies, as in all other parts of human nature, cannot be denied. It forms the basis of traits to be developed throughout life. Thus, although the environment plays a vitally important role, I believe that a genetic disposition towards crime is a prerequisite for regular criminal activity. Conversely, if this genetic disposition is regulated by a positive social and home environment, it is my belief that criminal tendencies can be suppressed by a more positive lifestyle.
The only conclusive paradigm created by the nature/nurture controversy is the fact that more study is required to enlighten the issue. The singular paradigms of nature vs. nurture have however changed to include both for their role in the psyche of the criminal. Primarily I believe nature is responsible for creating a criminal mind, with secondary influences from the environment, either at home or through socialization. It is hardly conclusive that all persons with in-born criminality would succumb to the urge to commit crime.
The fact that nature and nurture work together to create the criminal can be used to combat this process. It is mentioned above that parents with problems often have children with problems. A parent with criminal tendencies, who has been rehabilitated, can then help a child with the same tendencies to cope with problems experienced as a result.
A deeper understanding of the genetic nature of criminal tendencies can also help…