Decision fatigue

Have you ever come home exhausted from work and felt unable to even make the most simple decisions?  Or found half way through a big project that you simply don’t care any more and start making random choices?  Odds are you’re suffering from what psychologists have come to call “decision fatigue.”

Tony and I talked about decision fatigue this week on the Radio Live Home and Garden Show, what it is, how to recognise it and how to combat it.  (Click here for a link to the audio of the interview)

The most famous, and most quoted study to isolate this effect was carried out in Israel, looking at Judges decisions throughout the course of the day:


“Three men doing time in Israeli prisons recently appeared before a parole board consisting of a judge, a criminologist and a social worker. The three prisoners had completed at least two-thirds of their sentences, but the parole board granted freedom to only one of them. Guess which one:

Case 1 (heard at 8:50 a.m.): An Arab Israeli serving a 30-month sentence for fraud.

Case 2 (heard at 3:10 p.m.): A Jewish Israeli serving a 16-month sentence for assault.

Case 3 (heard at 4:25 p.m.): An Arab Israeli serving a 30-month sentence for fraud.

There was a pattern to the parole board’s decisions, but it wasn’t related to the men’s ethnic backgrounds, crimes or sentences. It was all about timing, as researchers discovered by analyzing more than 1,100 decisions over the course of a year. Judges, who would hear the prisoners’ appeals and then get advice from the other members of the board, approved parole in about a third of the cases, but the probability of being paroled fluctuated wildly throughout the day. Prisoners who appeared early in the morning received parole about 70 percent of the time, while those who appeared late in the day were paroled less than 10 percent of the time.

The odds favored the prisoner who appeared at 8:50 a.m. — and he did in fact receive parole. But even though the other Arab Israeli prisoner was serving the same sentence for the same crime — fraud — the odds were against him when he appeared (on a different day) at 4:25 in the afternoon. He was denied parole, as was the Jewish Israeli prisoner at 3:10 p.m, whose sentence was shorter than that of the man who was released. They were just asking for parole at the wrong time of day.” (Click here for the whole article)

This is decision fatigue.  Our mental capacity to make decisions can get exhausted, just like a muscle.  And just like a muscle it also needs fuel.  The above study also found that just after the Judges mid morning snack the chance of getting parole went up again.  Further studies have gone onto to isolate this phenomena, and show that making decisions also burns glucose.  And if we eat, our energy stores and our capacity to decide also goes up.

In everyday life anyone who has managed a large project, built or renovated a house or organized a wedding, for example, will know that the decisions are exhausting.  It also helps to account for why we shouldn’t go grocery shopping while we’re hungry: shopping is a series of decisions and if we don’t have enough fuel on board our brain makes bad decisions.  It’s also why the candy is by the checkouts: when we’re decision fatigued we crave sweet foods and we lack the willpower to resist them.

So what can we do about it?

  • Make plans before hand.  There is no obvious feeling of being “decision fatigued” so it can be hard to notice.  But best to anticipate it based on being tired.  Make a grocery list and stick to it.  Or shop online at a time when you’re not tired.
  • Eliminate decisions.  Set up habits or plans so you don’t have to decide.  Pilots do this, they utilize checklists and flow charts (if this, then that) to minimize decision fatigue.
  • Try to eliminate obvious “no” options quickly, and minimise your options.  Less options, less energy required.
  • Get other peoples input and opinions.  They may not be as fatigued!
  • Generally try not to make a lot of important decisions all at once, try to avoid doing things that require a lot of decisions or willpower at the end of the day and never on an empty stomach or late at night.  As a wise man once said, if you’re not sure, sleep on it.

Leave a Comment

  • Anwell Steve September 21, 2013, 5:36 pm

    Yes, I would agree that sometimes it’s more on the time frame that we make a good or poor decision. It’s about timing. But, creating poor decisions can be avoided if we are aware of the things to be done. Using a productivity software app for an instance will lessen your poor decisions because it will help you make plans ahead of time.

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