Abstract

Inspection of raw data sheets of 3 Ss who participated in H. Schmidt\'s (1969) highly successful automated 4-choice precognition experiments revealed a strong tendency for Ss to repeat their last call if it had been a hit. This effect occurred 86.1% of the time on high-aim trials, and a more modest 32.1% of the time on low-aim trials. There also were response biases following misses, but their nature differed among Ss. On high-aim trials, the hit rate was the same on the repeat-following-hit (R-F-H) trials as on other trials. In the low-aim trials, however, the hit rate was significantly lower on R-F-H trials than on other trials. Evaluation of the target distributions revealed a significant excess of repeats on R-F-H trials, but only for high-aim trials where the bias is inconsequential. The strong response biases noted in these data are inconsistent with the hypothesis that spontaneous responding is necessary for success in forced-choice ESP experiments.