Effects of Consciousness on the Fall of Dice: A Meta-Analysis

This article presents a meta-analysis of experiments testing the hypothesis that consciousness (in particular, mental intention) can cause tossed dice to land with specified targets face up. Seventy-three English language reports, published from 1935 to 1987, were retrieved. This literature describes 148 studies reported by a total of 52 investigators, involving more than 2 million dice throws contributed by 2,569 subjects. The full database indicates the presence of a physical bias that artifactually inflated hit rates when higher dice faces (e.g., the "6" face) were used as targets. Analysis of a subset of 59 homogeneous studies employing experimental protocols that controlled for these biases suggests that the experimental effect size is independently replicable, significantly positive, and not explainable as an artifact of selective reporting or differences in methodological quality. The estimated effect size for the full database lies more than 19 standard deviations from chance while the effect size for the subset of balanced, homogeneous studies lies 2.6 standard deviations from chance. We conclude that this database provides weak cumulative evidence for a genuine relationship between mental intention and the fall of dice.