They discriminated between events before and after the diagnosis of a chromosome aberration. Also, in order to analyse whether the conviction and the diagnosis could be related, they excluded all convictions up to 2 years before and 2 years after the diagnosis in a separate analysis. They also discriminated between persons diagnosed early and late in life, using the median age at diagnosis cut off point.
Table 1: Basic Characteristics of persons with Klinefelter’s syndrome (XXY) or 47,XYY.
Table 2: HRs (95% CI) for overall case-specific convictions without and with adjustment for education, retirement, cohabitation and fatherhood in mean with Klinefelter’s syndrome and 47,XYY.
Within the results they identified 208 persons with 47, XYY and 161 of those were at risk of an event. (Details are shown in Table 1). The HRs were lower in the cohort diagnosed late in life (Table 2). Adjusting for socioeconomic parameters reduced the total HR (excluding traffic offences) to a HR of 1.05 (95% CI 0.90 to 1.23) (Table 2), but it was still significantly increased in the subgroup of homicide.
Graph 1: Kaplane Meier plot of proportion of persons Graph 2: HRs convictions due to cause in 47,XYY
Convicted (excluding traffic offences) for the first time Syndrome compared to aged-matched men. Actual
In the background population (thin line) and in men Numbers of offenders (47, XYY/controls) is given in
With 47,XYY (bold line.) All were 15e70 years of age. parentheses.
The prevalence estimates of 47,XYY syndrome or variants thereof in Denmark suggests that lower intelligence has been contributing to the increased level of criminal and homicidal behavior in men with 37,XYY syndrome. Gotz et al investigated criminality and antisocial behaviour in unselected men with Klinefelter's and XYY syndrome were more likely to have a criminal record compared to controls and found this to be due to a lower Intelligence Quotient (n1/416). Gotz et al found no increase in the number of criminal criminal records and homicidal records among persons with klinefelter's syndrome compared with controls, possibly due to low power (n1/413).
The findings suggested that the association between crime rate and 47,XYY was reduced when adjusting for socioeconomic variables, such as level of education, retirement, cohabitation and fatherhood. Thus the increased risk of conviction among the cases of homicidal behaviour may partly or fully be explained by disadvantageous socioeconomic conditions. Although there may be a relationship between increased convictions and poor socioeconomic status in persons with sex chromosomal abnormal phenotype, the causal relationship cannot be established.
In addition, social problems marginalisation, lack of education, poverty, geographical location etc can affect the risk of criminal behaviour and of being detected as well as convicted. Socio Economic problems maybe a part of a chain of events and adjustment would therefore introduce confounding. However, having controlled for these factors, it was found that the total HRs for being convicted decreased and were no longer statistically significant to the homicidal group.
This cohort is suggesting that although the genetic mutations of XYY and Klinefelter's syndrome is the underlying base of criminal and homicidal behaviour, the socio-economic factors have a substantial influence to whether that underlying behaviour is triggered and emitted.
Nurture Influences on the Killer’s Psyche: Adoption Studies
A key criticism raised by research into genetics is that it cannot rule out the effect of environment. For example, twin studies may find a 68% concordance between monozygotic twins, however, if they are raised in the same home environment, then the chances are that they will be treated in a similar way by their parents/siblings and therefore the learning environment that they group in is likely to be a factor in their behaviour. Adoption studies attempt to rule this out by looking at children who have been adopted and have therefore been raised by adopted parents where there is no genetic concordance [similarity].
(67) Diagram showing the
Basic concept of adoption
Studies.
The rationale of the adoption studies was explaining criminal behaviour as the comparison of criminals with their birth parents, as well as their adopted parents. If in criminal behaviour, the child is more like their birth parents rather than adoptive, with whom they share the same environment, a genetic basis of criminality may be suggested. Conversely, if the child is more similar to their adoptive parents within criminal behaviour, the environmental aspect of criminology is favoured.
The Crowe adoption study (1972) compared a group of adopted children whose biological mother had a criminal record, to a control group of adopted children whose biological mother did not have a criminal record. It was found that if a biological mother had a criminal record, 50% of the adopted children also had one by the time they were 18 years of age. Within the group, only 5% of the adopted children had a criminal record by the time they were 18. This suggests that regardless of the changed environment, children seemed biologically predisposed to criminality.
Results from adoption studies have consistently revealed a relationship between biological parent criminal behavior and adoptee criminal income. The finding has been noted in the case of property crime, but not in the case of violent crime. Violent crime in adopted way offspring has been shown as non-relative to violent crime in biological parents.
Findings from the Danish Adoption Cohort suggest that violent crime may be genetically related to other types of behavioural deviance. In the Danish Adoption Cohort, there is an increased rate of schizophrenia in the adopted-way offspring of biological fathers who have been convicted of violent and homicidal crimes. The father violence-adoptee schizophrenia relationship cannot be accounted for by the potential confounding factors of rearing social status, age at transfer, knowledge of family history of crime, or a biological parent’s mental illness.
One of the most influential and widely cited adoption study on criminality was conducted by Sarnoff A. Mednick and Karl O. Christiansen in Denmark, where relevant data was easily available that demonstrated that criminality has a significant genetic component that interacts with environmental risk factors. Adoption studies that followed have had significantly similar results.
The twin, and family studies have been a common method to test on criminals to determine whether there is a correlation. When studying the criminals that are adopted children, both their biological and adoptive parents are used for the experiment, as well as the child themselves.
The first study involving adopted-way offspring dealt examined the genetics of criminal behaviour that proved children which were more likely to become criminals if their biological parents were offenders themselves. This study demonstrates that crime is correlated to be a hereditary factor. The study took place within the 1980s, Iowa. The study used 52 adopted-way offspring which were born into female offenders as their biological mothers.
Results of this experiment demonstrate that seven of the fifty two children had committed a violent criminal act, where only one of those children had an adoptive parent accused of a similar cime. The relationship between crime and adoption has exhibited evidence to property crime and not to violent crime in adopted vs non-adopted individuals and their adoptive parents or biological ones. Other socio-economic factors such as age and where the child was moved during adoption can affect the accuracy in the conclusions.
Even though the adoption study dealing with crime is performed all over the world, possible information has been declined, as they have been presumed to have been obtained from deficient adoption centres, and not conducted face to face. The study has been proven to be influenced by genetic factors, but the environment in which they’re brought up triggers the criminal traits within them. However, statistics are not 100% defined.
Nurture Influences on the Killer’s Psyche: The Labelling Theory
The environmental aspects of criminality and homicidal behaviour focus’ predominantly on adoptive-way families, however, these theories like the genetic factors dismiss the other predominant socio-economic factors that could enhance or ‘trigger’ the criminal and homicidal behaviour within the individual.
The labelling theory interprets the responses of others as the most significant factor in the understanding of how criminal and homicidal behaviour is both created and sustained. The labelling theory stems from the work of W.I Thomas who wrote; “If men define situations as real, they are real in their consequences.” Labelling is the assignment or attachment of a deviant or violent identity to a person by other, including by agents of social institutions.
Thus, the people’s reaction, not the action itself, produces deviance as a result of the labelling process. Once the label has been applied, the deviant label is difficult to shed from the individual's mind, therefore the individual performs deviant acts to adhere to their label.
The labelling theory exhibit how those with the power to label somebody deviant and to impose sanctions wield great power in determining the devance of the individual. The police, court officials, school authorities, teachers, and official agents of social institutions apply a label, this then stays with the individual for a substantial length of time.
Furthermore, as deviants are handled through complex organisations, bureaucratic workers “process’ people according to rules and procedures, rarely, questioning the basis for those rules or willing or able to challenge them.
Bureaucrats are unlikely to linger over whether someone labelled deviant deserves that label, even though they use their judgements and discretion in deciding whether to apply the label. This leaves tremendous room for social influence and prejudice to enter the decision of whether someone is considered a deviant.
Once the label of deviant is applied, it is difficult for the individual to recover a non-deviant identity. A prime example of this: once a social worker or a psychiatrist labels an individual as mentally ill, that person will be treated as mentally ill, regardless of his or her mental state. Pleas by the accused that he or she is mentally sound are typically taken as more evidence of the illness. A person’s anger and frustration about the label are taken as further support for the diagnosis. A person need not have engaged in deviant behaviour to be labelled as a deviant.
Adam Lanza, the perpetrator of the Sandy Hook Elementary School shooting, was said to have been labelled with ‘asperger's syndrome’ as well as described as ‘fidgety’ and ‘deeply troubled’. Similar to that of Nikolas Cruz, the perpetrator of the recent shooting within Stoneman Douglas High School, Florida. Whom was described as an ‘evil kid’, it was said he had been reported ‘time and time again’ for his deviant and psychotic-like behaviour.
Both Lanza and Cruz had been subject to the ‘labelling theory’ from both their peer groups as well as school officials and the general public. These labels of being “deeply troubled” and an “evil kid” impacted Lanza and Cruz in a way that made them actually believe that the “label” was what identified them as a person. Both Lanza and Cruz had been associated with these labels since early childhood, thus had not known differently and were not able to differentiate themselves from who they were as a person and their label of which had been associated with them.
Although the “labelling’ of both Lanza and Cruz may have impacted their perceptions of themselves, possibly being an influencing factor on their actions, there were no further investigations on whether this led to detrimental mental health problems or psychotic tendencies. Therefore it makes it difficult to elicit how far their ‘labels’ actually influenced them to carry out their shootings.
Conclusion
Theories of genetic influences within the killers psyche are reliable, however, are only factors influencing the killer traits within them, rather than the singular cause. The socio-economic factors such as the environment, parental care, bullying, and human needs play a large part unearthing the underlying motives and causes of homicidal criminal behaviour. Humans are the most intelligent species known to earth. We learn from experience. Hence, crime and homicidal behaviour are human acts that can develop as a reaction to an individual's surroundings, nurture.
There will always be a strong and vast debate about whether the driving force of the killer’s psyche is “nature” or “nurture”, however, the concept of “nature vs nurture” in terms of the “killer’s” behaviour is difficult to determine as one being the stand alone cause. This debate takes an interactionist approach [the environment triggers the genetic mutations which causes the homicidal criminal act].
Dr Soania Mathur, a Canadian Physician, stated “Genes are the gun, the environment pulls the trigger.” Mathur was suggesting that it is difficult to determine to what extent each of the factors influence the “killer’ traits within the individual. The “nature” and “nurture” aspects are easily identifiable with case studies and scientific research illustrating this, however, statistically it is not possible to measure the extent of quantifying impact.
My research suggests that the debate of “nature” and “nurture” in the context of the killers psyche is partially irrelevant as the individual would uncontrollably had been subject to both nature and nurture without intention. Thus there is a delicate balance between the nature and nurture proponents which both elicit different responses.