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Brain drain

Depleted brain power • 2 min read

A study of parole judges in Israel showed a significant difference in their rulings based on the time of day they were made. Judges ruled in favour of prisoners — 65% of the time — if the hearings were scheduled early in the day.

However, where a hearing was scheduled in the afternoon, there was almost zero chance of winning parole, regardless of the facts presented.

Interestingly, if the judges took an afternoon break, their disposition drastically changed, and parole was far more likely.

Take note if you are interviewing for a promotion...try to book a morning slot!



Remember, any muscle, be it physical, cognitive, or emotional, can be strengthened. For all you gym buffs out there, think of those times you’ve exercised to the point of fatigue — your arms and legs no longer function. The last thing you need is another set of burpees (dear more burpees!).

So, what happens when we exercise our brain to the point of fatigue?

Mental fatigue

The brain is no different to the rest of your body — it fatigues to the point where it will reduce in function. The ability to solve problems will then decrease, while the headspace to make difficult decisions will be reduced.

Psychological challenges require us to dip into depleted reservoirs of brain power. Just like our bodies, we need to give the mind a chance to recover and grow.

There is a lot of research out there which shows the significant impact of cognitive fatigue as we progress through our day.

Francesco Gino, a behavioural scientist at Harvard Business School, carried out a study which showed that the later one interviews in the day, the lower score one achieves. This is due to cognitive fatigue of the interviewers.

Mental fatigue in practice

The ability to perform mental tasks significantly reduces when we repeatedly exert our brains. Here are just a few of the negative impacts.

Decision making

The effectiveness of our decision-making suffers when we experience cognitive load from working on too many tasks at once. We are more likely to make a poor decision if we do not block off specific time for the cognitive task.

Problem solving

Problem solving requires creativity and creativity requires rest. Unless we take mental breaks, new ideas and thoughts are less likely to flourish.


Dips in motivation levels naturally occur when we become mentally exhausted. When our workload increases, coupled with our wellbeing decreasing, it’s hard to maintain the same levels of motivation.


Key takeaways

  1. The brain is no different to the rest of your body when it is pushed beyond its limits — it fatigues to the point where cognitive function is reduced.

  2. The impact of cognitive fatigue plays a key role in poor decision making, decreased problem solving capabilities and dips in motivation.

  3. Complete your most important tasks during the periods where you’re most alert, and be sure to take breaks to let your brain recover.


Think big. act small

Identify your most important tasks and choose a time to complete them when your energy levels are at their highest.

Don't waste your best hours on menial tasks.


Content sources

  • Forbes, How To Overcome Mental Fatigue, According To An Expert, Noma Nazish

  • Forbes, Is Pandemic Burnout Draining Your Motivation And Energy? Here's How We Can All Promote

  • Recovery, Naz Beheshti

  • Harvard Business Review, 6 Reasons We Make Bad Decisions, and What to Do About Them, Mike Erwin

  • Peak Performance, Brad Stulberg and Steve Magness

  • Proceedings of the National Academy of Sciences of the United States of America, Extraneous factors in judicial decisions, Shai Danziger, Jonathan Levav, and Liora Avnaim-Pesso

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