Interpersonal psi: Exploring the role of the sender in ganzfeld GESP tasks

This study was designed to explore the role of the sender in a ganzfeld ESP task, conceptually replicating Raburn and Manning’s (1977) manipulation of the presence of a sender and the receiver’s expectation concerning the sender’s presence. The authors conducted 40 trials with an opportunity sample of participant pairs. Ganzfeld sessions were run by an automated system that randomly selected 1 of the 4 possible conditions, with both the experimenter and receiver remaining blind to the selection. During no-sender trials the sender was engaged in an alternative psi task. Overall the mean z score based upon target ratings was below chance expectation (-0.10, r = - 0.10). There were no significant main effects of sender role (p = .765), receiver expectancy (p = .632), or interaction effects, contrary to Raburn and Manning. Moderate positive correlations were found between task performance and senders’ (r = .188) and receivers’ (r = .248) expectations of success. Positive correlations were found between performance and receivers having practised a mental discipline (r = .219). Overall, the results suggest that receiver expectancy may be more important than whether or not a sender is actually present.