Time of day effects on problem solving: When the non-optimal is optimal

Abstract In a study examining the effects of time of day on problem solving, participants solved insight and analytic problems at their optimal or non-optimal time of day. Given the presumed differences in the cognitive processes involved in solving these two types of problems, it was expected that the reduced inhibitory control associated with non-optimal times of the day would differentially impact performance on the two types of problems. In accordance with this expectation, results showed consistently greater insight problem solving performance during non-optimal times of day compared to optimal times of day but no consistent time of day effects on analytic problem solving. The findings indicate that tasks involving creativity might benefit from a non-optimal time of day. Keywords: AnalyticInsightProblem solvingTime of dayCreativity Acknowledgments This work was supported by National Institute on Aging Grant R37 AG04306 to Lynn Hasher and Rose T. Zacks. The authors would like to thank Cameron Harris, Molly Rundquist, and Bruce D. Burns for their help with this project. The authors would like to thank Caren Rotello, John Kounios, and Christian Schunn for helpful comments on an earlier version of this manuscript. Notes 1A small pilot study with 34 participants investigated the effect of time of day on insight problem solving. Results showed that participants in the non-optimal condition had a significantly higher overall solution rate (M = .51) than participants in the optimal condition (M = .26), t(32) = 2.68 MSe = .09, p = .01, η2 = .18.