Jordan Peterson on psychology: what the evidence says · JRE #877
“there's no evidence that there's any relationship between intelligence and morality.”
What the evidence says
Peterson asserted there is no evidence of any relationship between intelligence and morality. A 2025 peer-reviewed historical review in the Journal of Intelligence (MDPI), covering studies from 1941 through the 2020s, found the research record is mixed and contradictory rather than uniformly null: some studies (e.g., using Kohlberg's moral-judgment framework and the Defining Issues Test) report associations between measures of cognitive ability and stage of moral reasoning, while other studies, particularly with young children, find no significant correlation between intelligence measures and moral development or moral motivation. The review's authors explicitly note prior researchers, including Kohlberg himself, have long identified "contradictory results" in this area, and they attribute much of the inconsistency to methodological problems, such as how intelligence and moral development are each operationalized and measured, rather than to a settled absence of any relationship. Based on this literature, characterizing the evidence as showing "no relationship at all" overstates the actual findings, which are better described as inconsistent and methodologically contested rather than definitively null.