In the latest of a series of studies addressing the question of whether extra sensory perception (ESP) and psychokinesis (PK) are sufficiently distinct to merit separate terms, researchers from the University of Northampton and the University of Edinburgh, UK tested for both kinds of psi functioning using a common protocol, while also looking for evidence of experimenter effects.
Forty participants completed a computer-based greyhound racing game. Races occurred in blocks of twelve, and each participant completed two such blocks. One block of races was presented to the participants as an ESP task, while the other was presented as a PK task. However, unbeknownst to the participants, each block contained equal numbers of ESP and PK races in a random order.
Chris A. Roe and Russell Davey each served as an experimenter for half of the sessions, and after briefing each participant, rated the interaction for warmth, spontaneity, and positivity. The authors predicted that the sessions facilitated by Roe would be more successful because of his higher degree of experience in working with research participants and overall sense of 'ownership' of the project.
Overall, the performance of the participants on the ESP and PK games was better than what would be expected by chance alone, but not to a statistically significantly degree. However, for those greyhound races in which the ESP task was disguised, the performance of the participants was significant. As predicted, participants who had been briefed by Roe performed better than those briefed by Davey, and significantly so for the disguised ESP tasks.
Roe, C.A., Davey, R., & Stevens, P. (2006). Experimenter effects in laboratory tests of ESP and PK using a common protocol. Journal of Scientific Exploration, 20, 239-253.