LAUSR

Abstract Personality and individual differences have rarely played a role in human reasoning research, and the sparse previous work has focused on Big 5 personality factors and reasoning in a very general sense. The present research expands this by using the HEXACO model of personality as well as more specific traits (interpersonal trust and reciprocation ideology), and examines conditional reasoning across three theoretically significant domains (social contract, precaution, and descriptive contents). Across two studies, greater trust (higher interpersonal trust and less reciprocation wariness) was associated with better reasoning about conditional rules in general. Concurrently, greater conscientiousness and honesty-humility were differentially predictive of reasoning about social contracts and precautions, but not descriptive contents. Openness was associated with reasoning performance in Study 1 but not in Study 2, and other traits of interest in prior studies (extraversion, emotionality) consistently did not emerge as important predictors. Further research should examine in more detail the effects of individual differences and personality on reasoning, and if certain traits may predict domain specific reasoning abilities. Such findings can provide both a new and informative method for assessing theories of human reasoning, as well as integrate the fields of human reasoning and personality.