A meta‐analysis of mass‐media tests of extrasensory perception

Abstract

Some scientists have argued that recent meta‐analyses of many different types of parapsychological study suggest that extrasensory perception (ESP) might exist, albeit as a small effect. Large‐scale ESP experiments conducted via newspapers, magazines, radio and television can generate a huge number of guesses and offer researchers a way of quickly obtaining enough data to discover reliably whether such small effects actually exist. The experimental conditions used in mass‐media ESP studies are almost identical to most national lotteries (i.e. large numbers of people sitting at home attempting to guess the identity of a distant target) and so positive results from such studies would challenge the notion that lotteries are unpredictable. Meta‐analysis of eight ESP studies conducted via the mass media, representing over 1.5 million individual trials, indicate a very low, negative effect size (z / N1/2 = −.0046) whose overall cumulative outcome did not differ significantly from chance expectation (Stouffer z = −1.60). The paper discusses the implications of these results for the debate about the existence of ESP and its practical implications for lottery organizers.