The researchers investigated whether or not marriage affected delinquency and violence by genetic means. Beginning with the Addhealth adolescent survey data, they identified a sample of 2612 siblings consisting of twins, siblings and singletons. They looked at sequences of 103 genes that have been shown to be associated with aggression and risky behaviour. They compared the proportion of variance in delinquency and violence that can be explained by the sequences among married and unmarried individuals.
1. Married individuals show a significant decrease on delinquency and violence scales
2. The amount of variance in behaviour explained by the genes is significantly smaller in married individuals compared with non married, ‘suggesting that marriage may suppress the collective influence of the genes.’
3. The inhibiting effect on the genes is not seen among cohabiting couples
4. Controlling for issues such as selection, age and non homogeneous population did not alter the results.
‘Our results suggest that marriage is associated with lower levels of antisocial behaviour and the inhibiting effect appears to be pronounced among married people, but not among cohabiting couples”
Although the authors readily admit that the study has limitations and studying the influence on behaviour of genetic factors is complex, the study is consistent with the conclusions of previous social science research: that married people are less violent and that marriage is good for society. The study gives a novel insight into one of perhaps many mechanisms by which marriage does this.
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