Ruiz, F. J., & Luciano, C. (2012). Improving international level chess-players’ performance with an acceptance-based protocol. The Psychological Record, 62, 447-461.
This study compared an individual, 4-hr intervention based on acceptance and commitment therapy (ACT) versus a no-contact control condition in improving the performance of international-level chess players. Five participants received the brief ACT protocol, with each matched to another chess player with similar characteristics in the control condition. Experimental participants showed significant reductions in the believability and interference of general, unpleasant private events during competitions as well as reductions in the frequency of the treated counterproductive reactions to private events (FCR). Also, as indicated by an objective chess performance measure (ELO performance), all participants in the experimental condition improved their performance during the 7 months after the ACT protocol in comparison to the 7 months prior; however, none of the control participants improved their chess performance. Pretreatment levels and initial changes in FCR and believability significantly predicted the effect sizes on chess performance in the experimental condition.