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

Lay people's beliefs about how minds relate to bodies are more complex than previously recognized, forming a multidimensional construct rather than a single dimension. Items once used to measure a unidimensional belief actually capture two distinct constructs: belief in substance dualism and reductive physicalism. These two constructs differently predict belief in free will and two types of determinism across two studies. Additionally, two fundamental personality traits—preference for experiential versus rational information processing—predict those metaphysical beliefs theorized to be based on subjective phenomenological experience and rational deliberation, respectively. Beliefs about mind-body relations thus have unique predictive abilities beyond a simple one-dimensional view.

Study at a glance

Abstract

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.