A SHEEP GOAT EFFECT IN REPETITION AVOIDANCE - EXTRA-SENSORY PERCEPTION AS AN EFFECT OF SUBJECTIVE-PROBABILITY

Performance on extra‐sensory perception (ESP) and on subjective random generation (SRG) has been shown independently to differ along a number of personality dimensions. One of the variables known consistently to influence ESP performance but not studied yet in SRG experiments is belief in the paranormal. We report three experiments on subjective randomness as a function of belief in ESP: (1) a retrospective analysis of randomness in multiple choice answers of a telepathy experiment revealed that believers in ESP (‘sheep’) avoided repetitive responses significantly more than non‐believers (‘goats’); (2) in an experiment where subjects had to produce random strings of the digits 1−6, sheep avoided repetitions significantly more than goats; (3) in an experiment where subjects had to compare equiprobable short random sequences, sheep underestimated the number of mathematically expected repetitions significantly more than goats. In all three experiments a stronger bias against the incidence of direct repetitions was found for subjects believing in ESP than for those denying its possibility. This may indicate that believers are more prone to an illusion of causality in the face of everyday coincidences. We suggest that effects of subjective probability and, particularly, of subjective randomness should be considered in future studies concerned with individual differences in ESP scoring. 1990 The British Psychological Society