Creativity is often perceived as an unpredictable event, the product of an unexpected “Aha!” moment. But a pair of Michigan psychologists, Mareike Wieth, of Albion College, and Rose Zacks, of Michigan State University, decided to research the concept. They discovered that problems requiring a flash of illumination to solve are best approached during the time of day when thinkers are not actually at what they feel is their peak.

Reporting their findings in the journal Thinking and Reasoning, they assigned 428 students to fill out a questionnaire with 19 questions, including, “What time would you get up if you were entirely free to plan your day?” and “How much do you depend upon an alarm clock?”

Participants were categorized as morning, evening or neutral types and randomly assigned to a morning or afternoon testing session. Some problems were analytic in nature, others were inspiration-based. While the more logical type of problem solving showed no statistical difference, morning people scored higher on the insight-demanding challenges in the late afternoon, and vice versa.

Wieth and Zacks believe the results depend upon an inhibitory process that suppresses distracting information. It is thought that this system performs less efficiently when individuals are less alert, allowing random thoughts to enter the decision-making process, resulting in more creative thinking.