Meta-analysis on belief in free will manipulations

Abstract

Whether free will exists is a longstanding philosophical debate. Cognitive neuroscience and popular media have been putting forward the idea that free will is an illusion, raising the question of what would happen if people stopped believing in free will altogether. Psychological research has investigated this question by testing the consequences of experimentally weakening people’s belief in free will. The results of these investigations have been mixed, with successful experiments and unsuccessful replications. This raises two fundamental questions that can best be investigated with a meta-analysis: First, can free will beliefs be manipulated and, second, do such manipulations have downstream consequences? In a meta-analysis across 146 experiments (95 unpublished) with a total of 26,305 participants, we show that exposing individuals to anti-free will manipulations decreases belief in free will, g = -0.29, 95% CI = [-0.35, -0.22], and increases belief in determinism, g = 0.17, 95% CI = [0.09, 0.24]. In contrast, we find little evidence for the idea that manipulating belief in free will has downstream consequences after accounting for small sample and publication bias. Together, our findings have important theoretical implications for research on free will beliefs and contribute to the discussion of whether reducing people’s belief in free will has societal consequences.