Psychology 4102/5102 (Carey)
Genes and Antisocial Behavior

Background: Serious crime and violence are of intense public interest. The available data on twins and adoptees, largely derived from epidemiological studies in Scandinavia, suggest a moderate degree of heritability for antisocial behavior. The estimates of heritability for a large number of different measures of antisocial behavior cluster in the intermediate range, much like those for personality traits.

Instructions: Write a two to three page (double spaced typewritten or handwritten equivalent) response to the questions given below. You will be graded on your ability to bring the principles of behavior genetics gleaned throughout the lectures and the readings on ALL the course material into your answers. You will also be graded on clarity and succintness of expression, so try to turn in a polished report.

1. From the synopsis given above and from the heritability estimates for behavioral traits presented in class give ballpark figures for the correlations of MZ twins, DZ twins, and biological parent-adopted away offspring for antisocial behavior

2. McGue et al., in their article on intelligence, suggest that heritability of a phenotype may change with age. What would you predict would be the heritability of antisocial behavior over the lifespan? What would you expect the environmental correlation between siblings to do over the lifespan?

3. One of the major research thrusts in behavior genetics is to figure out the pathways that start at DNA and end in antisocial behavior. Obviously, thousands of years of primate evolution has not given us a gene with a sole purpose of income tax evasion or joyriding in a stoeln car. Give a plausible model of your own of different psychological mechanisms that might be heritable and influence antisocial behavior.

4. Suppose that a friend tells you "If crime is genetic, then rapists, murders, etc. are not responsible for their behavior and should not be severely punished." Give an intelligent response to your friend's opinion specifying how much blame or absolution you think should be accorded to a criminal offender.

5. Suppose that it is discovered that a rare dominant gene is associated with some cases of severe pedophilia. (Pedophilia is a condition in which individuals, almost always males, are sexually attracted to young children.) Males with the gene have a 50% chance of having sex with young boys or young girls. Suppose that a pedophiliac who has the gene is in prison for repeated child molestations is about to be paroled.

6. Some people argue that research aimed at finding genes for such phenotypes as aggression, antisocial behavior, and violence should not be done at all. Others argue that the search for these genes should be postponed until the ethical and legal questions are sorted out. Yet others say that finding a "genetic marker" may help unlock the neurobiology of aggression and violence and thus is a worthwhile goal. Give your viewpoint and the reasons for your position on this issue.