Feeling the future: A meta-analysis of 90 experiments on the anomalous anticipation of random future events

Abstract

In 2011, one of the authors (DJB) published a report of nine experiments in the Journal of Personality and Social Psychology purporting to demonstrate that an individual’s cognitive and affective responses can be influenced by randomly selected stimulus events that do not occur until after his or her responses have already been made and recorded, a generalized variant of the phenomenon traditionally denoted by the term precognition. To encourage replications, all materials needed to conduct them were made available on request. We here report a meta-analysis of 90 experiments from 33 laboratories in 14 countries which yielded an overall effect greater than 6 sigma, z = 6.40, p = 1.2 × 10-10 with an effect size (Hedges’ g) of 0.09. A Bayesian analysis yielded a Bayes Factor of 1.4 × 109, greatly exceeding the criterion value of 100 for “decisive evidence” in support of the experimental hypothesis. When DJB’s original experiments are excluded, the combined effect size for replications by independent investigators is 0.06, z = 4.16, p = 1.1 × 10-5, and the BF value is 3,853, again exceeding the criterion for “decisive evidence.” The number of potentially unretrieved experiments required to reduce the overall effect size of the complete database to a trivial value of 0.01 is 544, and seven of eight additional statistical tests support the conclusion that the database is not significantly compromised by either selection bias or by “p-hacking”—the selective suppression of findings or analyses that failed to yield statistical significance. P-curve analysis, a recently introduced statistical technique, estimates the true effect size of our database to be 0.20, virtually identical to the effect size of DJB’s original experiments (0.22) and the closely related “presentiment” experiments (0.21). We discuss the controversial status of precognition and other anomalous effects collectively known as psi.

The future failed: No evidence for precognition in a large scale replication attempt of Bem (2011).

“…For the correlations, we calculated power with respect to a small but meaningful correlation in the literature between a variable of our questionnaire and retroactive free recall (Bem et al, 2015). 3 Toward this goal we chose the correlation between stimulus seeking and the psi factor in Experiment 8 (free recall) of Bem (2011; r = 0.22, p = .015).…”

“…However, extraordinary claims require extraordinary evidence and empirical data which are good enough for a priori plausible claims may not be good enough for less probable claims such as that psi can be scientifically proven. Even Bem stated that the requirements for evidence of precognition are “extraordinary” (Bem et al, 2015). In the present study, the correlation between supernatural beliefs and precognition did not occur systematically across experiments.…”

“…This article is intended solely for the personal use of the individual user and is not to be disseminated broadly. NO PRECOGNITION EFFECTS effect size which we found for the specific studies (priming and free recall, respectively) in the metaanalyses of Bem et al (2015). Using this smallest effect size that is plausible, we calculated power analyses for each experiment.…”

“…However, power analyses should also be conducted using the smallest effect sizes which were interpreted as meaningful in previous studies (Dienes, 2008(Dienes, , 2021. Toward this goal, we used the smallest effects which could be interpreted in favor of the psi hypothesis of the meta-analysis by Bem and colleagues (Albers & Lakens, 2018;Bem et al, 2015). 1 We used the lower boundary of a 90% confidence interval (CI) of these effect sizes as a threshold for a potential interesting effect.…”

“…It is therefore astonishing that some research groups have found empirical evidence for the existence of precognition. The accumulated evidence includes successful replication attempts of Bem's study, including significant meta-analyses of forced-choice guessing and precognition experiments and presentiment experiments indicating that the human body can detect stimuli occurring in the future (Bem et al, 2015;Honorton & Ferrari, 1989;Mossbridge et al, 2012Mossbridge et al, , 2014Radin, 2004;Radin et al, 2017). The authors of one meta-analysis of 90 replication attempts of Bem's experiments from 33 laboratories in 14 countries reported an overall effect of d = 0.18 and a Bayes factor exceeding the criterion value of 100 for decisive evidence in support of the psi hypothesis (Bem et al, 2015).…”