Hello I was just wondering if anyone could please tell me how many marks this essay would get out of 24marks for genetic factors in aggression thanks.
The claimthat aggression can be inherited through genes has been studied by a largenumber of psychologists. Twin studies have been particularly useful forexploring this biological explanation, and has allowed psychologists to lookchiefly at genes; especially in monozygotic twins. Rutter found a higher concordance in aggression for MZ twins than DZtwins, suggesting that the more similar the genes are, the more likelythey share genetic behaviour such as aggression. Coccaro found that nearly 50 % of the variance in direct aggressivebehaviour in adults was attributed to genes and 70% of verbal aggression.However, this research also contradicts the role of genetics in aggression, asit gives equal weighting to environmental factors, which the other 50% of the variance is attributed to. This brieflyoutlines the gene-environment interaction approach, with a geneticpredisposition reacting with the environment to influence aggressive behaviour.Adoption studies have also helped to differentiate between the complicatedcontributions of environment and heredity in aggression. If the adopted childand their biological parents display aggressive behaviour, it is likely thatgenetics play a stronger role than upbringing in a different environment Hutchings and Mednick studies 1400 adoptionsin Denmark and found that a significant number of adopted boys with criminalconvictions had biological parents (usually fathers) with criminal convictions.This supports that genetics influence aggression, as there is evidently acorrelation even when separated from biological parents and the sameenvironment. There is a problem that the only aggression measured was criminalconvictions however, as it may not have picked up on antisocial behaviour notcaught. In fact, with only studying criminal convictions, the psychologistscould have ignored those who are arguably more intelligent and aggression- nothaving been caught and getting away with the crime.
There aresome problems with twin studies. The first being that although MZ twins have ahigher concordance rate for aggression in comparison with DZ twins, the concordance rate is never 100%.This suggests that genetic factors are not the only factors for aggression andenvironment does play a part. A predisposition for violence, but a disciplinedand supportive home environment may stop this behaviour being a problem.Another problem is that MZ twins look exactly the same, and share the samebiological makeup. This would affect how society treats the twins, perhaps thesame way. In this instance, DZ twinswould be treated more like individuals, and would therefore show more variancein their behaviour.
With bothmethodologies, criminality may bestudies more than aggression, which affects internal validity. Thismeans that the study fails to differentiate between violent and non-violentcrime; an individual may have a convictionfor fraud and placed in the same category as an individual in prison formanslaughter. Another issue is thathabitual violence may be a better indicator for aggression, but again isplaced in the same category as a one-off crime (a person who became aggressiveonce after consuming alcohol and bumping into someone they both had a mutualhatred for each other). Mednick et al found the biggest effect in their studywas for non-violent crime. Brennan,however, compared the criminal history of adopted males and their biologicaland adoptive parents. They found that genetic influences were significant incases of property but not violent crime. This piece of research showsthat a crime personality may be inherited rather than aggressive behaviour.Being in a demonstratively moral and supportive environment teaches childrennot to be aggressive instead of becoming desensitised to it in a geneticallylikely household with many convictions.
Genderbias has also been criticised in the study of the role of genetics inaggression. Button et al found that thegenetic heritability of aggressive anti-social behaviour was much higher forgirls than boys (this was not the case for non-aggressive anti-socialbehaviour such as truancy). Button’s research indicates that heritability isstronger in women than men when it comes to aggression, and that more researchwould need to be taken for females. This may also explain the lower concordancein same sex DZ twins.
Otherpsychologists have explained the genetic link to aggression with a single gene-the MAOA. This warrior gene is linked with aggression, with lower levelsincreasing aggression. This may be dues to the role it has on regulating the metabolism of serotonin on the brain, withlower levels increasing aggression. Brunner studied a Dutch family with the males showing high levels ofviolence (convictions and high antisocial behaviour levels). The studyfound abnormally low levels of MAOA, showing that deficiencies causeaggression. This study is culturally bound, and may not be demonstrative of thelink between aggression and genes around the rest of the world. However, agene-environment explanation may carry more weight. Caspi conducted a meta-analysis with 500 male children. He found thatlow levels of MAOA in the children did concord with antisocial behaviour,supportive of this explanation, however only if maltreated as a child.This shows that social environment plus genes influences behaviour, rather thanjust one or the other. Moffat found asimilar conclusion. By examining abuse, convictions, violence and antisocialbehaviour in 422 males from New Zealand, low levels of MAOA correlated with therisk of being convicted but again, only if they had suffered abuse. Allof these studies are based on male aggression, with no incidences of femaleaggression. This is a weakness, which means that genes can only be shown toinfluence aggression on men.
Researchinto MAOA on aggression, like twin and adoption studies, focuses on individualswho have been convicted of violent crimes. This means that the studies onlyinvolve aggressive individuals who have been caught- who may tend to be low-intelligence individuals. This mayexplain why many studies fail to find evidence of genetic influences onaggression. They also fail to explain cultural differences which suggests thatgenetics are not the only factors in aggression, otherwise it would beuniversally correlated. In this way, the MAOA gene’s studies are ethnocentric, unable to be generalisedto other countries.
However,research into this gene may be useful for society and the individual. Morley and Hall suggest that information fromgenetic screenings could be used to devise new treatments for personalitydisorders that have been identified as risk factors for criminalbehaviours. The treatment would be able to lower the risk of the person beingput in prison, and create a safer society. However, there are ethical weaknesseswith this. This is rather deterministic,stating that the person will be aggressive after being labelled with MAMOdeficiencies and is not pleasant for the person. Because it is their geneticmakeup, this may seem like their personality is being altered when there isreally only 50% variance linked to aggression. It could be useful when environmental factors pose a risk for those alsowith low levels of MAOA.
Manystudies of genetic influences on aggressive behaviour rely on self-reports andthese studies tend to show that there is a genetic link for aggression.However, observational studies have not been consistent. Miles and Carey found less genetic influenceon aggression through observation than with self-reports in a meta-analysis.A replication of Bandura’s Bobo study using twins found no difference in MZ and DZ twins, suggesting that individualdifferences in aggression were more of a product of environmental influencesthan genetics (Plomin). Thisresearch suggests that many studies into MAOA are inconsistent, and the linkfound is unpredictable. Morley and Hallargue that genes associated with aggression only poorly predict thelikelihood that an individual will display aggressive behaviour. The presenceor absence of environmental factors can’t be identified in a genetic text,making the prediction of aggression even less likely. Perhaps agene-environment interaction is a better explanation, with those who arepredisposed genetically and brought up in a low socio-economic background more pronethan those predisposed and brought up in a higher socio-economic environment inan area with low crime rates. If both genes and environment are not goodpredictor, then used in synchronisation will increase the accuracy.
The role of genetics is reductionist, as is states that aggression iscaused by a single gene to make it easy to test. It ignores complex biologicalfactors as well as psychological and environmental factors. For example, MAOAdecreases low serotonin levels. Lowserotonin levels are correlated with increased risk for depression. Itcould be that they are testing depression in males, as aggression and violenceare symptoms of male depression (especially if they had suffered mistreatmentas a child). It is also determinist, showing that aggression isdetermined by our genes and that we can treat people with “faulty” genes. Thebiological approach ignores free willand this reduces individual responsibility for aggression, a significantproblem when addressing an issue which is frequently dealt with in court and isharmful to society.