Extraversion and performance at a forced-choice ESP task with verbal stimuli: two studies

Two studies were conducted to explore the putative relationship beteween extraversion and performance at a forced-choice ESP (FC-ESP) task while avoiding possible artefacts associated with group testing and with providing ESP test feedback before completing personality measures. In Study 1, 80 participants were tested individually and completed two measures of extraversion - Eysenck's (1963) EPI Form A, and Costa & McCrae's (1985) NEO-FFI scale - before completing a 45-trial FC-ESP run. Each trial consisted of a set of five thematically related words. The response sheet was presented - following the Anderson-White technique - as a 5 x 45 table printed on a sheet of A4 paper attached to a sealed opaque envelope that contained individually produced target lists. All sessions were invigilated by the second author. The overall hit rate was 9.21, which does not deviate significantly from mean chance expectation (MCE) of 9.00 (1-sample t(79) = 0.62, p = 0.54). As predicted, performance did covary positively with extraversion scores on the EPI measure (r = 0.21, p = 0.03), but did not on the NEO measure (r = 0.05, p = 0.34). In Study 2, 49 participants completed two 20-trial FC-ESP runs using word-based and Zener symbol stimuli presented as in Study 1. They also completed Eysenck's short-form EPQ-R (Eysenck, Eysenck & Barrett, 1985). Performance on both tasks was only marginally better than MCE of 4.00 (for Zener stimuli, M = 4.24, 1-sample t(48) = 1.02, p = 0.16; for word stimuli, M = 4.37, 1-sample t(48) = 1.28, p = 0.10). The correlation between extraversion and FC-ESP performance on the word-based task failed to reach significance (r = 0.17, p = 0.13), but the relationship with performance on the Zener task was significant (r = 0.36, p = 0.01). No relationship was evident for either task with neuroticism, and conducting partial correlations between extraversion and ESP scores that controlled for neuroticism gave negligible differences from zero-order correlations. Psychoticism showed a marginally significant negative relationship with performance on the word task but not with the Zener task (r = -0.26, p = 0.04 and r = 0.01, p = 0.47 respectively).