Experimental Studies of the Differential Effect in Life Setting (Parapsychological Monographs No. 13)

In the introductory chapter, the authors give a brief review of previous laboratory studies of ESP. They attribute the lack of consistency in findings to the large number of uncontrolled variables. Also, they observe that motivation and adjustment are the two most outstanding variables that affect the subject's ESP performance. They say that only when personal involvement is sufficiently high can the influence of other variables affecting ESP be overcome. Further, they note differential responses of certain subjects who score positively under one set of circumstances and negatively under another.

Using a life situation as a setting for students at Andhra University, Waltair, India, to insure a high degree of motivation and personal involvement, the authors carried out four experiments to show differential effects of change in circumstance. The students were applicants for admission to certain university courses in three of the experiments, and applicants for employment in the library in the other experiment, 131 subjects in all. The subjects were given clairvoyance tests (two 50-card runs with ESP cards) using a blind-matching technique before they had an interview with Professor Rao, who would accept or reject them for the course or employment. After the interview they were given two more 50-card runs. The tests were administered by P. Sailaja and B.K. Kanthamani. During the interview, Professor Rao rated the students on several personality variables, including confidence and nervousness, according to clinical observation, using a five-point scale.

From findings in the preliminary experiment, it was hypothesized that subjects would score fewer ESP hits before than after the interview, the effect being more pronounced in the first 50 trials than in the last 50. Also, subjects rated as nervous would score more hits per run than those rated as confident. Results of two confirmatory experiments gave support to the first of these findings. The t tests of significance of the difference between pre- and post-interview ESP scores in the first replicatory experiment were 5.14 for the first 50 runs and 3.26 for the last 50 runs. In the second confirmatory experiment, the t test for the first 50 runs was 3.76 and for the last 50 runs, 1.54. Subjects rated as nervous scored more hits per run in the first confirmatory experiment, but not in the second.

In the fourth experiment, the ESP scores of students who had prepared in advance to expect a "psychological test" as well as an interview were compared with scores of students not so prepared. The "prepared" students showed significantly more differential between pre- and post-interview scores than the unprepared students, t = 2.15. The authors consider a set of test preparedness as well as motivation and personal involvement to be crucial factors in differential ESP scoring.