Why do people vote against their self-interests? Those attracted to social dominance are less empathetic. Empathic response is predominately organized in the right hemisphere (see Decety and Jackson, 2004, for a meta-analysis). This is certainly evidence for the hemisphericity theory of political orientation.
Among humans, the social value of dominance behavior is seen in the rapid increase in support for social dominance during successful periods of warfare. Across species, dominant animals are more responsible for defense and territorial acquisition, and can provide many benefits to those lower in the social hierarchy. Thus, an attraction to dominance has been under considerable Darwinian pressure.