Demand characteristics and indirect suggestion effects in psychological experiments

Description

While it is widely accepted that demand characteristics (cues which inform participant beliefs about experimental hypotheses) can drive genuine change in experience in medical research (i.e., placebo effects), this has received relatively little attention in other fields. There are stable individual differences in the ability to alter subjective experience in accordance with one’s goals: the capacity for phenomenological control (e.g., in response to imaginative suggestion). In this talk I will argue that people can use phenomenological control to meet the goal of being a ‘good participant’ in experiments by having the experiences they believe they are expected to have, without being aware they are doing so. Consistent with this proposal, I will present experimental evidence that some well-known effects (ownership of a fake hand, ‘ASMR’ tingling and visually-evoked auditory sensation) can be produced by phenomenological control, and correlational evidence that measures of these, and other effects are substantially predicted by trait phenomenological control (measured by response to imaginative suggestion), while classic visual illusions (e.g., Müller Lyer and Ebbinghaus illusions) are not. Finally, I will briefly consider methods for addressing this issue as an experimental confound and discuss some other contexts in which phenomenological control may be operative.

Speaker Bio:
Peter Lush is a Senior Research Fellow in the School of Psychology at the University of Sussex. His primary research interest is phenomenological control (the capacity to generate experience in accordance with one’s goals) and its role in a variety of social contexts (e.g., in psychological experiments, medical situations and ‘hypnosis’). He also works on methodological issues relating to demand characteristics and demand effects in psychology research, as well as the experience of intention.

Period	11 Dec 2025
Held at	Human-Computer Interaction and Design
Degree of Recognition	International