Is There a Best Time of Day to Make a Decision?

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When you have an important decision to make do you do it in the morning, afternoon or evening. Or does it matter to you? Do you make a decision on an empty or full stomach?

These questions have been the subject of recent research which finds for the most part that the time of day does affect decisions and performance, and that time of day is optimal in the morning for most people.

Research shows that as the time of day progresses, our mental resources and cognitive functioning declines. The result is often fatigue and underperformance.

Research studies have shown that persistent and escalating cognitive fatigue can result in problems with motivation, distraction, and mistakes in information processing, and cumulatively, burnout.

Scientists Shai Danziger, Jonathan Levav, and Liora Avnaim-Pesso published a study in which they examined 1,112 bench rulings in a parole court which summarized the proportion of favorable judgments over the course of the day. They found that judges were more likely to deny a prisoner’s request for parole as the day progressed.

By the time the lunch break took place the proportion of favorable rulings was close to zero. When court was back in session in the afternoon, the pattern repeated itself, starting high and ending with almost zero favorable rulings towards the end of the day. Clearly a decline in energy was a contributing factor, the researchers concluded.

Time of day can affect performance. Hans Henrik Sievertsen of the Danish National Centre for Social Research, Marco Piovesan of the University of Copenhagen, and Francesca Gino found that published a study that shows that time of day affects students’ performance in schools. Using test data on the full population of 8- to 15-year-old children in Danish public schools from school years 2009/10 and 2012/13 they measured the effect of both time of day and breaks on students’ performance on standardized tests. The researchers found that cognitive fatigue resulted in students’ declining performance, and that a break, with a meal recharged their energy.

Nessa Bryce in Scientific American Mind cited a series of studies done at Harvard University and the University of Utah that found that employee’s ethical and moral compass is much more accurate in the morning when they had more energy than later in the day.

Argentinian psychological scientists turned online chess matches to see if time of day affected performance.

The large databases of time-stamped competitive chess games allowed the researchers to examine variations in decision-making in various times in the day.

The research team, which included Maria Juliana Leone (who won a Woman International Master chess title in 1999) and APS Fellow Mariano Sigman, found that decision-making abilities fluctuated during the day: In the morning chess players’ decisions tended to be slower but more accurate, whereas later in the day decisions were made more abruptly with less accuracy.

When we make decisions during the day, research shows that we have individual differences in circadian rhythms, called chronotypes. These chronotypes affect when people go to sleep and when they wake up.

People who prefer to stay up late are called “owls” and people who prefer to get up early are called “larks.”Other individuals are somewhere in the middle.

Chronotypes have been shown in several studies to influence a wide range of behaviors, including whether people are prone to cheating. Another study published in Psychological Science concludes that morning people tended to be most ethical in the morning whereas evening people tended behave more ethically in the evening.

Read my latest book: Toxic Bosses: Practical Wisdom for Developing Wise, Moral and Ethical Leaders.



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Ray Williams

Author/Retired Executive Coach-Helping People Live Better Lives and Serve Others