A free will needs a free mind: Belief in substance dualism and reductive physicalism differentially predict belief in free will and determinism

In this article, we show that lay people's beliefs about how minds relate to bodies are more complex than past research suggests, and that treating them as a multidimensional construct helps explain inconclusive findings from the literature regarding their relation to beliefs about whether humans possess a free will. In two studies, we found that items previously used to assess a unidimensional belief in how minds relate to bodies indeed capture two distinguishable constructs (belief in substance dualism and reductive physicalism) that differently predict belief in free will and two types of determinism (Studies 1 and 2). Additionally, we found that two fundamental personality traits pertaining to people’s preference for experiential versus rational information processing predict those metaphysical beliefs that were theorized to be based on subjective phenomenological experience and rational deliberation, respectively (Study 2). In sum, beliefs about mind-body relations are a multidimensional construct with unique predictive abilities.