Effects of Expectancy on Cognitive Training: A Systematic Review and Meta-Analysis

The expectancy effect refers to the influence that an individual’s beliefs and motivations may exert on performance, thereby affecting the outcomes of a cognitive intervention. Current literature presents inconsistent findings regarding cognitive gains derived from cognitive training, and the influence of participants’ expectations on these outcomes has not yet been systematically synthesized. This study aims to address this gap by quantifying the impact of expectancy on cognitive performance and identifying the most effective strategies for its induction in training contexts. To this end, a systematic review followed by a meta-analysis will be conducted. The methodology will adhere to PRISMA and Cochrane guidelines. Experimental and quasi-experimental studies that evaluate expectancy interventions in cognitive training will be included, with outcomes encompassing a range of cognitive functions such as attention, memory, and executive function. Searches will be conducted across eight electronic databases for studies published between 2000 and 2025, without language restrictions. Eligibility will be determined according to PICOS criteria, and study selection and data extraction will be performed independently by two reviewers. The meta-analysis will combine data to estimate the effect size of expectancy and examine potential moderating factors, based on the systematization of study characteristics. The findings aim to advance understanding of the role of expectancy in cognitive training, enabling researchers to achieve greater control of variables in future cognitive training interventions. The results are expected to contribute to the design of more effective and methodologically rigorous interventions in the field of cognitive training.