Aggressive Behaviour In Males example essay topic

'Such incredulity about a 'gene for crime' - the label that has, inevitably, attached itself to an inborn tendency to offend - is surprising, as nobody denies that crime is inherited. ' (Jones, S (1996) ) In the passage above Jones suggests there is a societal disapproval for the notion that crime can be reduced to a single gene (a purely biological explanation for crime). This disapproval of a biological cause for crime is contrasted against Jones' own view that nobody denies that crime per se is inherited. It may be reasonable to assume that the acquisition of a criminal lifestyle is preferably seen to be social rather than biological.

Discuss the above statement with respect to the psychobiological evidence and social factors. From Jones, S. (1996). In the blood: God, genes and destiny. Flamingo The controversial field of behavioural genetics has been researched into thoroughly, with supported claims for a genetic base of behavioural attributes such as aggression and impulsivity. A growing scientific focus on genes and behaviour has contributed to the recovery of genetic determinism, the belief that genetics is a major contributing factor in determining behaviour. This biological approach can be substantially invalid by the likes of B.F. Skinner.

The behaviorist would lead you to believe that the environment was the predetermining factor in the origins of behavioural characteristics. This highly contentious subject can be argued for eternity but each side of the debate puts forwards some interesting findings, suggesting that maybe this field can be explained by a correlation between genetic and social factors. Men, in general, are far more aggressive than women, which leads to the question, are males born that way or do environmental factors contribute? A study by John Toot on rats established that nature, not nurture holds the answers. The levels of neurotransmitters in various brain regions of the rats were measured, the findings highlighted that the male rats had significantly lower levels of dopamine and serotonin in the amygdala, a brain region associated with aggression. These finding would therefore suggest that aggressive behaviour in males might be attributed to the decreased amygdala serotonin influenced by the Y, male chromosome.

On studying Toot's findings, Daniel Ely proposed that identifying this Y chromosome might enable the detection of high-risk aggressive males and subsequently manipulating their levels of serotonin to contest their hostile tendencies. In theory, Toot and Ely suggest a logical explanation and possible cure but identifying the Y chromosome has become a problem and further studies have contradicted their findings. Furthering Toot's findings in France, Saudou, F (1994) genetically engineered mice to explore the possibilities of a criminal gene. His findings were supportive of biological aspects in that their brains quintessentially lacked one type of receptor for the chemical serotonin. The low levels of serotonin were linked to impulsive violence, suicide, alcoholism and depression. The missing 5-HT-1 B receptor was found to be vital in the production of the neurotransmitter, therefore Saudou suggested that the participation of this specific receptor might lead to aggressive behaviour.

Similar studies were carried out on mice in the United States. Scientists found that abnormalities in brain chemicals can turn mice into violent, predatory animals. Oliver Cases et al. discovered that mice lacking in monoamine oxidase A (MAO A) were very aggressive as adults. Researchers at Johns Hopkins University genetically engineered mice in order to study strokes, but their finding lead to astonishing revelations in the world of behavioural genetics. The mice that committed violent acts essentially lacked a gene that was responsible for the production of the neurotransmitter, nitric oxide.

As with Toot and Ely the researchers in this case speculated that, "it is highly possible that the behavioural abnormalities we have observed are direct, selective consequences of the loss of n NOS (the enzyme responsible for the formation of nitric oxide) and not secondary to global physiological disruptions". Raine and colleagues were determined to support the genetic al side of the debate, as they believed that people from good families in good neighbourhoods carried out most crimes of a gruesome nature. They set about to prove their theory by taking PET scans of 41 murderers brains, in particular the functioning of their prefrontal cortical. Dysfunction in this area of the brain is linked to personality and emotional deficits, the findings suggested that those without histories of social deprivation had lower prefrontal glucose metabolism thus supporting Raine's initial predictions. These findings lead Raine et al. to speculate that, "the 'social push' to violence is minimised, and consequently, the brain abnormalities provide a relatively stronger predisposition to violence". In 1848 an on-the-job accident led to major discoveries into medical history and how the brain controls behaviour and emotions.

Phineas Gage, a railroad worker was the victim of a horrific accident that subsequently enlightened the world of behavioural science. Gage suffered horrendous injury when a metal rod shot through his skull, entering his left cheek and exiting through the top of his head. Previously Gage was known to be polite and sociable but the long-term effects of his injury changed his behaviour considerably. He became antisocial, foul-mouthed and an unrepentant liar, although the consequences of Gage's accident did him no favours, it did teach researchers about the critical role of the frontal lobe area of the brain.

The injury damaged the frontal lobe area, which is responsible for controlling behaviour and emotions. This would suggest that damage to this area of the brain might alter the norm behaviour. On the other hand, Lawrence Labbate et al. reported that damage to the frontal lobe area could in fact cause some patients' behaviour to improve. "Frontal brain trauma may occasionally cause acceptable changes in behaviour". This is contradictory to the findings involved in Gage's case but as we have already established this area of biological research is highly debatable and all research will be contradicted at some point. Many studies have enlightened us with respect to the fact that our genes may determine our aggressive tendencies, but most studies so far have been on genetically engineered animals.

It is fair to say that studies on adoptive children can shed some light towards this controversial debate. Edwin J.C. G van den Oord et al. (1994) compared 221 pairs of biologically unrelated siblings in adoptive families, the report revealed that, genetic influences accounted for 70% of the variance of aggressive behaviour. The experiments of Zing Yang Kuo supported the social side of the debate, Kuo concluded that 'behaviour of an organism is a passive affair'. E ibl-Eibesfeldt (1959) agreed with Kuo's experimental findings, saying that "aggressive behaviour can be enhanced or inhibited by experience, but that it has to be learned in order to occur". The findings of Scott and Kuo in the late 1950's summarised the fact that aggression is learned, rather than an expression of an innate drive.

This statement separates behavioural psychologists into the social opposed to biological side of the debate. The influential Skinner was the predecessor of this environmental learned approach to behaviour. Now that the social issues in the determination of aggression are being addressed it is necessary to ask the question, as humans are we all entirely free agents that make our own choices? i.e. are we able to make the decision to be aggressive? Determinism identifies the immediate causes of human behaviour and tries to establish whether they are social or environmental.

Psychologists have always been concerned with the idea of free will and determinism, as this will inevitably lead to the answers. On the other side of the debate it is obvious that aggression is an essential part of human instinct. It will be argued that aggression is not only a valuable part of individual human nature but also an important component in the structure of society. This may seem extreme that society needs aggression, but it is only when the aggressive drive becomes frustrated that it becomes dangerous. From this it is fair to say that there is not a simple 'instinct to fight', but instead an internal mechanism that all humans posses which once stimulated produces anger. The discussion on the biological and social aspects contribution to aggression suggests many possible explanations.

The geneticists would question how long it will take before science uses genome mapping to study for chromosomal defects that may lead to criminal tendencies. It has been thoroughly established that research within this field favours animal studies, but there is no reason to believe that the basic cause of human aggression is different to what we see in animals. Therefore the findings from such studies will never establish whether or not genes play a greater or lesser role in regulating aggressive behaviour in humans or animals. 1310 Words

Bibliography

Edwin J.C. G van den Oord et al (1994) A study of problem behaviours in 10 to 15 year old biologically related and unrelated international adoptees.
Behavioural Genetics, Vol. 24, No. 3 Kuo, Zing Yang, ' Genesis of the Cat's Response to the Rat', from instinct (Princeton: Van Nostrand, 1961) p.
24. Labbate, L (1997) Salutary change after frontal brain trauma.
Annuals of Clinical Psychiatry, Vol. 9, No. 1 pp. 27-30 Raine, A (1998) Prefrontal glucose deficits in murderers lacking psychosocial deprivation.
Neuropsychiatry, Neuropsychology and Behavioural Neurology, Vol. 11 No. 1, pp. 1-7 Saudou, F. et al (1994) Enhanced aggressive behaviour in mice lacking 5-HT- 1 B receptor.
Science, Vol. 265 Scott, J.P. Aggression (Chicago: University of Chicago Press, 1958) Toot, J et al (2001) Sex differences in brain monoamine's and aggression, American Physiological Society, Pittsburgh.