Nature versus nurture controversy
The theory of nature versus nurture pertains to the controversy on whether inherent qualities of a biological organism, which is depicted as “nature”, is related or influenced by the experiences, condition or situation of that particular species (“nurture”). The concept the human being develop specific behavioral patterns based on their environment is termed tabula rasa or blank state. This notion is considered to be a major influence in the development of an individual. These external settings of an individual play a major role in the psychology of an individual, including his anti-social, aggression and criminal behavior. It has thus been questioned for several decades whether criminals are born or could these particular individuals emerge after successive events in their lives that result in the transformation of a normal individual to a criminal.
To date, there is much debate over the mechanism behind the entire concept of criminality. Biologically or non-biologically influenced, criminality remains an elusive subject that still needs to be comprehensively analyzed. The 19th century classic report of Phineas Gage regarding the anti-social behavior that emerged after massive damage of the prefrontal cortex of his brain from a railroad accident is now considered as the birth of the field of forensic neurology (Harlow, 1848). Today, computerized imaging of his fractured skull has shown that the autonomic and social nerve systems are the specific damages that were affected, thus resulting in a totally different individual. Such observation, together with research results gathered from war veterans, has led to the conclusion that violent criminal behavior is caused by injuries to the frontal lobe of the brain. It has then been proposed that injury to the prefrontal cortex of the brain causes a condition that has been coined as acquired sociopathy or pseudopsychopath (Blair and Cipolotti, 2000). It is interesting to know that there is an 11% reduction in the size of the grey matter of the prefrontal cortex among patients diagnosed with anti-social personality disorder (APD) (Raine et al., 2000). A related observation has also been observed between intelligence and alterations in the grey matter of the prefrontal cortex.
The temporal lobe of the brain has also been determined to influence an individual’s emotional response and aggression, wherein lesions in the amygdale of the temporal lobe result in an individual’s failure to recognize fear and sadness among the faces of other people (van Elst et al., 2001). The connection between the decreased expression of the monoamine oxidase A enzyme and reactive violence has already been established (Caspi et al., 2002). Monoamine oxidase A is responsible for the catabolism of monoamines such as serotonin (5-HT). The working hypothesis currently accepted is that the prefrontal-amygdala connection is altered, resulting in a dysfunctional aggressive and violent behavior, resulting in criminality in particular individuals.
Earnest A. Hooton (1887 – 1954) is a highly acclaimed physical anthropologist and evolutionist. His work is significant to our current scientific concept of crime because he persistently attempted to prove that criminal have biologically distinct characteristics from non-criminals. His anthropological work on physical differences based on a population of approximately 13,873 male prisoners from 10 different states across the United States. His results strengthened his claim on the biological causes of violence and aggression and that his claimed that criminal behavior is a simple representation of an inferior type of human species that has degenerated. Unfortunately, Hooton was inadequate in integrating the concept of population genetics into his research because he haphazardly took 3,023 men from the general population to conduct a comparative analysis of physical differences. His measurement of foreheads, eyelids, ears, cheekbones, jaws, chins and shoulders resulted in a confusing supportive evidence for his claim. He explained in one of his published works that biology plays a major role in the development of individuals and society and that the environment is wrongly blamed for any failure that befalls an individual (Hooton, 1939). The research claim of Hooton had sparked more effort into determining the basis behind criminality. Other researchers from different fields of specialization ridicules Hooton’s work, describing it as the comical attempt in defining criminal behavior. The general reaction to Hooton’s claim that criminals are biologically inferior was condemned. Sociologists refused to accept the notion that physical unattractiveness is strongly correlated to criminal behavior.
Blair RJ and Cipolotti L (2000): Impaired social response reversal. A case of ‘acquired sociopathy’. Brain 123:1122–1141.
Caspi A, McClay J, Moffi tt TE, Mill J and Martin J (2002): Role of genotype in the cycle of violence in maltreated children. Science 297:851–854.
Harlow J (1848): Passage of an iron bar through the head. Boston Med Surg J 13:389–393.
Hooton EA (1939): Crime and the man. Cambridge, MA: Harvard University Press.
Raine A, Lencz T, Bihrle S, LaCasse L and Colletti P (2000) Reduced prefrontal gray matter volume and reduced autonomic activity in antisocial personality disorder. Arch Gen Psychiatry 57:119–127.
van Elst LT, Trimble MR, Ebert D, van Elst LT (2001) Dual brain pathology in patients with affective aggressive episodes. Arch Gen Psychiatry 58:1187–1188.