Steven Crane Compiled Section Handouts. Human Behavioral Biology 2012

How do genes influence aggression?
Genes have something to do with it: aggressive rat strains and breeds of dog are enough to show that much.

What are "the genes related to aggression" usually doing in a direct sense?

• Modulating pain thresholds

• Making a rat better able to detect the pheromone of a competitor

• Or just genes for higher general levels of arousal (including affiliative behavior)

What are some candidate genes for aggression? What are the issues with the studies?

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  Review: MAO (monoamine oxidase) degrades serotonin in the synapse. Allelic variants of MAO are associated with various profiles of aggressive behavior in humans.
  
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    But remember, it’s a gene-environment interaction. The "bad" version only makes for more aggression if it's coupled with childhood abuse.
    
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  Dopamine receptor genes come in allelic variants that have some association with aggression in adulthood.
  
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    But these are actually more about impulsivity, sensation-seeking, and risk-taking.
    
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  How about XYY males?
  
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    It was all a myth in the Richard Speck case. No evidence that sex chromosomal abnormalities predict violence.
    

How does culture influence aggression?

Which traditional models of subsistence show the highest aggression?

• Pastoralists most likely to have a warrior class than farmers or hunter-gatherers.

• Pastoralists tended to colonize the American South. What violence patterns do you see in the South?

  • It's a culture of honor. And when honor is at stake, that's where violence comes out (at much higher rates than in the North).

    • Low threshold for perceiving an insult

    • Culture of readily responding to insults with violence

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