(Un)Great Expectations: The Role of Placebo Effects in Cognitive Training

• Published in: Journal of applied research in memory and cognition 2018-12, Vol.7 (4), p.564-573
• Main Authors: Tsai, Nancy, Buschkuehl, Martin, Kamarsu, Snigdha, Shah, Priti, Jonides, John, Jaeggi, Susanne M.
• Format: Article
• Language: English
• Subjects: Brain Training; Cognition; Female; Human; Learning; Male; Placebo; Short Term Memory
• ISSN: 2211-3681; 2211-369X
• DOI: 10.1037/h0101826

A growing body of literature demonstrating the malleability of critical higher-order cognitive functions by means of targeted interventions has incited widespread scientific interest, most notably in the form of cognitive training programs. The results are mixed and a point of contention: It has been argued that gains observed in cognitive training are mainly due to placebo effects. To address this, we examined the effect of participant expectations on one type of cognitive training that has been central to the controversy, namely n-back training, by inducing beliefs about expected outcomes. Participants receiving n-back training showed improvements in non-trained n-back performance regardless of expectations, and furthermore, expectations for positive outcomes did not result in any significant gains in an active control group. Thus, there was no detectable expectancy effect in either direction as a function of the cognitive intervention used, suggesting that training-related improvements are unlikely due solely to a placebo effect. General Audience Summary The brain training industry is an estimated billion-dollar industry but mounting concerns revolve around the genuine efficacy of training programs. Invested consumers have been left with little scientific guidance, however, and no study to date has tested whether positive training findings are indeed solely due to the placebo effect, as some have suggested. In the current study, we directly address this issue and ask whether participant expectations for particular outcomes account for training outcomes. We provide new evidence that positive expectations are neither necessary nor sufficient in garnering favorable outcomes for those receiving a sterile training program. But for those in the experimental training program, we find that those who trained improve, even in the presence of negative expectations.