Mental Training for Better Achievement: Effects of Verbal Suggestions and Evaluation (of Effectiveness) on Cognitive Performance

Abstract

Objective: There is only some literature regarding the influence of verbal suggestions on cognitive performance in healthy volunteers. For example, the performance in a knowledge test was enhanced when participants were told that they had subliminally received the correct answer. However, enhancing cognitive performance only via verbal suggestions without prior conditioning phases has not yet been examined. The goal of our study was therefore to investigate the effects of a mental training based on verbal suggestions compared to a control training on cognitive performance in a student population using a balanced-placebo-design.Methods: In total, 103 participants were randomly assigned either to listening to a 20 min audio-taped mental training or to a 20 min philosophy lecture (control training) via headphones. Participants were individually tested before and after the training concerning their cognitive performance. Information about the type of training were varied in both intervention conditions (“You are part of our experimental condition and you will receive an effective mental training” or “You are part of our control group and you will receive the control condition”). At the end of the assessment, participants were asked what kind of training they believed they had received and how effective they would rate the received training.Results: Overall, the cognitive performance improved in all participants, F (1, 99) = 490.01, p < 0.001. Contrary to our hypotheses, we found no interaction of the type of training and type of instruction on the cognitive performance. Participants who rated the received training as being effective at the end of the experiment (regardless if it was the mental or the control training), have before experienced a greater improvement in their cognitive performance [F (2,100) = 7.26, p = 0.001] and showed higher scores in the ability to absorb [F(2, 99) = 3.75, p = 0.027].Conclusion: The subjects' own experiences in the task might have influenced the rating of the training rather than the actual training or the information they receive regarding the type of training. This finding underlines the relevance of enhancing the subjective beliefs and self-efficacy in situations where cognitive attention processes are important and of individually tailoring mental trainings.

Placebo- and Nocebo-Effects in Cognitive Neuroenhancement: When Expectation Shapes Perception

“…Furthermore, our findings are limited to healthy adults. As stated by Fuhr and Werle (17), psychological interventions for enhancing cognitive performance might even be more effective for patients with impaired cognitive functioning, e.g., when suffering from an affective disorder. Patients might be more susceptible to expectancy manipulation and might benefit both subjectively and objectively, for example, due to better concentration, greater motivation, and higher perceived self-efficacy.…”

“…In one of the very few studies manipulating performance expectation without pill administration, Fuhr and Werle (17) found neither an effect of a mental training based on verbal suggestion nor of the information about the effectiveness of the training on actual cognitive performance. In one of the few studies including both a placebo and a nocebo instruction, the expectation that a tone of a specific frequency will improve or impair cognitive performance strongly affected perceived, but not actual cognitive performance (18).…”

Effects of Expectancy on Cognitive Performance, Mood, and Psychophysiology in Healthy Adolescents and Their Parents in an Experimental Study

“…Concerning placebo effects on cognitive performance, recent studies have focused on the role of expectancies about the effectiveness of the intervention (post hoc subjective outcome). In some cases, rather the expectancies affect objective cognitive performance than the sole information of receiving an intervention (42)(43)(44). High prior expectations can increase post hoc expectancies about the intervention, yet they do not necessarily affect objective cognitive outcomes (45).…”