Causation is a fundamental way to make sense of both social and non-social domains. High levels of autistic traits have been linked to enhanced rationality, suggesting a more normative way of reasoning. We aimed to systematically compare causal reasoning tendencies across social and non-social domains and evaluate their relation to self-reported autistic traits and thinking styles. We used a causal reasoning task with three binary (present/absent) variables forming common cause networks (X←Z→Y) representing social and non-social domains. Causal mechanisms in the social domain represented social relationships, while causal mechanisms in the non-social domain represented economics and meteorology. We recruited 76 participants from the general population and measured their levels of autistic traits and thinking styles on self-reports. We found that participants consistently violated the normative rules of causal reasoning. We also identified systematic differences across domains. However, we did not identify meaningful differences between clusters of reasoners in their levels of self-reported autistic traits and thinking styles. We conclude with that people violate the normative rules of causal reasoning differently across domains. However, we cannot conclude that this relates to levels of autistic traits or thinking styles. Lay Abstract We regularly think about cause-and-effect relationships in the world around us. Previously, researchers reported that people with higher levels of autistic traits reason more consistently and rule-based. However, they have not compared social, involving living things, and non-social, involving non-living things, worlds in relation to people's levels of autistic traits. We used a causal reasoning task to test this. In this task, there were causal scenarios with binary variables, meaning a variable can be either present or absent. The scenarios either reflected a non-social mechanism, for example, economics, or a social mechanism, for example, an interpersonal relationship. Our participants, who did not necessarily have a clinical diagnosis, completed this task and two self-report questionnaires. We found that people did not follow the rules of causal reasoning. We also found that people's responses differed between social and non-social scenarios. We found that this was unrelated to people's self-reported autistic traits and thinking styles. We are confident that people differ in their use of reasoning rules in their causal reasoning, and this happens differently between social and non-social scenarios. Highlights People consistently violate the normative rules of causal reasoning. This happens differently across social and non-social domains. Neither the levels of self-reported autistic traits nor thinking styles differ between the clusters of decisive and indecisive reasoners, yet further exploration is suggested.
