Kouchaki, M., &Smith, I. H. (2014). The morning morality effect: The influence of time of day on unethical behavior. Psychological science, 25(1), 95-102.

Are people more moral in the morning than in the afternoon? We propose that the normal, unremarkable experiences associated with everyday living can deplete one’s capacity to resist moral temptations. In a series of four experiments, both undergraduate students and a sample of U.S. adults engaged in less unethical behavior (e.g., less lying and cheating) …

Wieth, M. B., &Zacks, R. T. (2011). Time of day effects on problem solving: When the non-optimal is optimal. Thinking &Reasoning, 17(4), 387-401.

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 …