Abstract

Reviews the background of "psi" phenomena, the apparent ability to receive information shielded from the senses and to influence systems outside the sphere of motor activity, and reports on a series of psi experiments by H. Schmidt (1969). The objections of critics of these experiments are discussed in some depth. It is concluded that the possibility of sensory cues, machine bias, cheating by Ss, and experimenter error or incompetence cannot reasonably account for the significant results. In addition, less detailed reviews of the experimental results in several broad areas of psi research indicate that psi results are statistically replicable and that significant patterns exist across a large body of experimental data. Commentaries on the present article follow in the same edition of this journal.