A debate that continues to spawn controversy in many scientific disciplines is on the topic of heredity and the influence genetics has on the overall character of a human being. More commonly referred to as the ‘Nature versus Nurture’ debate, scientists as well as the average citizen are intrigued as to what determinants shape personal character as well as individual behavior. There are several factors that impact an individual’s destiny and through various studies, explanations, and theoretical models it becomes very apparent that one isolatable factor is nearly impossible to distinguish.

It is widely accepted that the model for the development of human behavior is extremely fluid and effected by several factors, not just genes or environmental factors alone but in fact an interaction between the two. There are several important theories that do not advocate the influence of heredity or environmental factors over one another but in fact display the importance of their interaction in determining an individual’s behavior. An individual’s genetic disposition is important in that it lays down a fundamental framework that can be a guide for propensities of certain courses of action. It is a fact that someone may be born with the disposition for a higher than average intelligence but environmental factors play a tremendous role in how this trait would be expressed. If an individual were to grow up in an environment that fostered the pursuit of academic interests, this intellect trait would have the ability for increased expression rather than if the individual were in an environment that placed little value on learning. This can in turn relate to criminal behavior and social deviance. Various developmental and sociological factors play a role in an individual’s inclination towards exhibiting criminal behavior. This section will focus more on social and environmental factors that have been shown to influence behavior. Individuals with certain genetic dispositions may be effected more than those without these traits but in all situations it has been determined that these factors can be attributed to shaping criminal behavior.

Perhaps one of the most fundamental studies influencing scientific opinions of nature vs. nurture would be a study done comparing monozygotic versus dyzygotic twin pairs (Christiansen, 1977). In this study, twin pairs were examined for the concordance of criminal behavior for both twins. This is a study of particular interest because both sets of twins were raised in the same environment but in one case, the case of the monozygotic or identical twin sets, the siblings are genetically identical where as in the other case, the case of the dyzygotic or fraternal twin sets, the siblings are merely genetically similar. The MZ twin pairs were found to have a 50% concordance (in one out of two cases both twins exhibited criminal behavior) where in the DZ cases there was only 21% concordance. This illustrates a strong correlation of genetics and criminal disposition but it also indicates the relative importance of environmental factors as well; environmental factors influence criminal behavior, which explains why there is not a 1:1 correlation of genetic disposition and criminal behavior.

An additional study was performed more recently (Mednick, Gabrielli, and Hutchings, 1984) where family psychology vs. biological heredity in determining criminal behavior was examined. This study was done using identical twins that were adopted by two different families and raised apart from each other. It was observed that adopted children are as aggressive as their adoptive parents rather than their biological parents. The results from both studies indicate that environment and genetic disposition are equally as responsible in shaping human behavior.

One of the most important environmental factors during childhood development is that of socialization or the way a child is ‘taught’ how to act. This refers to the period of childhood development when children learn the rules and values of their society. This model hypothesizes that initially children learn to merely obey the rules of their society. Certain actions are repeated because of directly correlated consequences. A child does not intuitively know that stealing is wrong; they have to be taught through negative consequences that this behavior is not acceptable. They then internalize these rules and eventually believe them to be fundamentally correct. In other words, socialization refers to the developmental period where the ideals of morality and socially acceptable behavior are instilled in a child. If a child is consistently taught how to act through both positive and negative reinforcement, the child will begin to exhibit certain characteristics because they believe them to be inherently correct. If a child is not taught how to properly act or inconsistently reinforced, clear-cut moral obligations may not be instilled leading to effected social judgment and a disposition towards criminal behavior.

An important point to make is that levels of education have been determined to be significant in the manifestation of criminal behavior. Individuals with learning disabilities have been shown to be more prone to violent behavior. The major reason for this is given in an interrelated causal pattern of events with education at the center. School achievement is predictive of pro-social behavior or behaviors designated as upholding the moral values of a society. This is because academic achievement is interrelated in our society with several other variables such as financial success, high self-esteem and an internal locus of control. This particular model may account for reasoning behind the general idea that individuals with a high IQ generally have fewer tendencies for criminal behavior than individuals with a low IQ. The hypothesis is that having a higher IQ results in easier achievement in school. As stated above, doing well academically is associated with several societal factors as well. Individuals with a lower IQ may not succeed as much academically which would result in lower self-esteem and not as much financial success, resulting in an increased disposition for criminal behavior. It is important then to stress education and to address issues with learning disabilities at an early age to disallow the appearance of these negative attributes.

Learn about some of the legal aspects of genetic screening.

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