We analyze the results of a large-scale experiment wherein subjects participate in a hypothetical primary election and must choose between two fictional candidates who vary by sex and race. We find evidence of affinities along these dimensions in voting behaviour. A number of phenomena regarding these affinities and their interactions are detailed and explored. We find that they compete with each other on the basis of race and gender. Neuroeconomic metrics suggest that people who vote for own race candidates tend to rely more on heuristics than those who do not.