The link between violence and inequality testifies to the sensitivity to low social status. Although homicide is an extreme form of behavior, marking one end of the spectrum of social relations, high homicide rates are indicative of a more aggressive quality of social relations in society more widely. Competition and cooperation are simultaneously material and social relationships. Social and material relationships are mutually defining. Even among nonhuman primates there is evidence that being groomed by another animal creates a social obligation to come to the aid of the groomer when necessary. As well-being becomes more dependent on individual material achievement and less dependent on the strength of the social relations, interaction becomes more self-serving and competitive, people trust each other less, they withdraw from social and community activities, and aggression becomes more common. Dominance hierarchies and territoriality are just two of the common ways of reducing conflict.