Psychologists have also considered examining speciesism as a specific psychological construct or attitude (as opposed to speciesism as a philosophy), which was achieved using a specifically designed Likert scale. Studies have found that speciesism is a stable construct that differs amongst personalities and correlates with other variables. For example, speciesism has been found to have a weak positive correlation with homophobia and right-wing authoritarianism, as well as slightly stronger correlations with political conservatism, racism and system justification. Moderate positive correlations were found with social dominance orientation and sexism. Social dominance orientation was theorised to be underpinning most of the correlations; controlling for social dominance orientation reduces all correlations substantially and renders many statistically insignificant. Speciesism likewise predicts levels of prosociality toward animals and behavioural food choices.