Extraversion and ESP performance: a meta-analysis and a new confirmation - extrasensory perception

Journal of Parapsychology, The, Sept, 1998 by Charles Honorton, Diane C. Ferrari, Daryl J. Bem

A NEW CONFIRMATION

Extraversion data is available for 221 of the 241 subjects in a series of ESP ganzfeld studies reported by Honorton, Berger, Varvoglis, Quant, Derr, Hansen, Schechter, & Ferrari (1990) and conducted at the Psychophysical Research Laboratories (PRL) in Princeton, NJ. The experimental procedures are described in detail in the Honorton, et al. (1990) report.

Subjects

The subjects were 131 women and 90 men. Their average age is 37 years (sd = 11.7). This is a well-educated group; the mean formal education is 15.5 years (sd = 2.0) and belief in psi is strong in this population. On a seven-point scale where "1" indicates strong disbelief and "7" indicates strong belief in psi, the mean is 6.20 (sd = 1.03). Personal experiences suggestive of psi were reported by 88 percent of the subjects; eighty percent reported ostensible telepathic experiences. Eighty percent have had some training in meditation or other techniques involving internal focus of attention. One hundred and sixty-three subjects contributed a single ESP ganzfeld session and 58 contributed multiple sessions.

Extraversion Measure

Extraversion was measured using the continuous scores of the Extraversion/Introversion (EI) Scale in Form F of the Myers-Briggs Type Indicator (MBTI; Briggs & Myers, 1957). The MBTI was not used in any of the meta-analysis studies. The MBTI EI Scale is constructed so that scores below 100 indicate extraversion and scores above 100 indicate introversion. (For consistency with the meta-analysis, we have reversed the signs so that positive correlations reflect a positive relationship between ESP performance and extraversion.) The mean EI score for the PRL subjects is 100.36 (sd= 25.18).

ESP Measure

ESP performance was measured using the standardized ratings of the target and decoys (Stanford's z scores; Stanford and Sargent, 1983). Stanford z's were averaged for subjects with multiple sessions.

Results

Overall results. The correlation between ESP performance and extraversion in the PRL series is significant (r= .18,219 df, t= 2.67, p = .008, two-tailed, 95% CI from .05 to .30). This outcome is very close to the meta-analytic estimate for free-response studies (r= .20) and the difference between the two correlations is nonsignificant (Cohen's q = .02, z = -0.26, p = .793, two-tailed).

Ganzfeld Novices. The results are similar if we restrict our analysis to the five PRL Novice series with inexperienced subjects who each completed a single ganzfeld session. MBTI data is available for 190 of the 205 Novices and the mean weighted r for the five series is .17 (z = 2.25, p = .024, two-tailed, 95% CI from .02 to .31). The ESP/extraversion correlations are homogeneous across the Five series ([[[Chi].sup.2].sub.4] = 2.88, p [greater than] .05). Eleven subjects in the first Novice series (Series 101) completed the MBTI between six and eighteen months after their ESP ganzfeld session and we did not maintain records of their identity. However, the results are essentially the same when this series is eliminated. The mean weighted r for the remaining four Novice series is .19 (z = 2.30, p = .021, two-tailed, 95% CI from .03 to .34).