Early birds, save your creative challenges for just before bed. Your least productive time of day may be the perfect opportunity for a moment of insight, according to a study from a recent issue of Thinking & Reasoning.

Mareike Wieth, an assistant professor of psychological science at Albion College, and her colleagues divided study participants into morning types and evening types based on their answers on the Morningness Eveningness Question­naire (those who scored in the neutral range—about half of initial respondents—were excluded). Wieth instructed them to solve three analytic problems and three insight-oriented ones. No time-of-day effect was found for analytic problem solving, but subjects’ performance on tasks requiring creative insight was consistently better during their nonoptimal times of day.

Wieth believes this effect is the result of a reduction in inhibitory attentional control—the ability to filter information that is irrelevant to the task at hand. “This less focused cognitive state makes people more susceptible to think about other, seemingly unrelated information—like things they experienced earlier or their to-do list,” she explains. “This additional information floating around in your mind during your nonoptimal time of day ultimately helps you reach that creative aha! moment.”

This article was published in print as "Sleepy Brains Think Freely."