How experimenters influenced participants in the ganzfeld parapsychology experiment

An analysis of conversations that took place during ganzfeld parapsychology experiments has revealed researchers may have exerted an influence on their participants.

Ganzfeld experiments involve a 'sender' trying to project images from a video clip to a 'receiver' who is incubated, blindfolded, in a sound-proof room. The 'receiver' reports the images they believe they are receiving to a researcher who notes them down. Crucially, the next stage involves the researcher reviewing these images with the 'receiver', before the 'receiver' attempts to identify the video clip seen by the 'sender' from among three decoys.

Robin Wooffitt analysed recordings taken from ganzfeld experiments held at the famous Koestler Parapsychology Unit in Edinburgh during the mid-1990s. He found that as the researchers reviewed the images reported by the 'receivers', they tended to respond in two distinct ways.

After a clarification by the 'receiver', researchers sometimes said "okay" and moved decisively onto the next item. Other times, however, they said "mm hm" with an inquiring tone. After hearing this, 'receivers' typically tried to expand on their description, and as they did so, often ended up casting doubt on the clarity of their own imagery.

Wooffitt said that a researcher's choice to respond with "okay" or "mm hm" might seem inconsequential, but in fact the latter utterance clearly had an effect on the 'receivers" confidence in their imagery. Consequently, he said, "it is at least possible that they [the 'receivers'] will have less confidence in relying on their imagery to identify significant events or themes in the video clips."

If the researchers did influence participants in this way, could it help explain why sceptical researchers have tended to report more negative results than believers? Wooffitt told the Digest: "I think it has much more to do with the nature of one's interactional style, and that doesn't necessarily correlate with either sceptical or 'pro-paranormal' beliefs."

Wooffitt added that by furthering our "understanding of the impact of the social dynamics in psychology experiments more generally", his observations have implications beyond parapsychology research.

Further reading

Wooffitt, R. (2007). Communication and laboratory performance in parapsychology experiments: Demand characteristics and the social organisation of interaction. British Journal of Social Psychology, 46, 477-498.