BIOLOGY AND THE DEEP HISTORY OF HOMICIDE

Social science historians are discovering deep patterns in the history of homicide rates. Murders of children by parents or caregivers correlate inversely with fertility rates and appear to be a function of the cost of children relative to parental resources and to parental ambitions for themselves and their children. Murders among unrelated adults correlate with feelings towards government and society. These patterns may represent facultative adaptations to variable or unstable habitats (including social habitats) that may favour the nurture or neglect of children in the first instance, or cooperation or aggression among unrelated adults in the second. Human neural and endocrine systems may have evolved to facilitate such shifts in behaviour.