On average, the Chinese, Koreans, and Japanese are more similar to each other and are different from Australians, Israelis and the Swedes, who in turn are similar to each other and are different from Nigerians, Kenyans, and Jamaicans.

He theorized a heritable component in altruism and developed Genetic Similarity Theory which is an extension of W. His theory was that Muslims have an aggressive personality with relatively closed simple minds and were less amenable to reason. If they choose not to they must write one research paper.

Rushton's controversial work came under attack within the scientific community for the quality of the research and attacked by some even for being "racist". Rushton was a Fellow of the American British and Canadian Psychological Associations[citation needed] and onetime Fellow of the John Simon Guggenheim Memorial Foundation.