Does repeating a task improve mental fitness?

Or are we doomed to make poor decisions forever?
16 May 2017


A brain sparking with electricity.



When we exercise our bodies we get tired and have to stop after a bit. Eventually we get fitter and more enduring at those tasks. I know we can suffer fatigue and certain mental faculties too - decision fatigue springs to mind. If we perform difficult mental tasks does our endurance of those tasks improve over time or are we doomed to make poor decisions in the afternoon forever?


Izzie Clarke put this tiring topic to Duncan Astle from Cambridge University...

Duncan - Just as with physical activity, difficult mental activities show big practice effects - that is the more you do them, the better you get. Carefully controlled studies have shown that practicing difficult mental activities like remembering all of the objects within a picture can make you much better at those tasks and this improvement can be mirrored by changes in the brain. For example, the brain areas involved in attention and memory can become more strongly connected by this kind of practice.

Izzie - Just like with physical exercise, mental practice can improve our skills. But, if I go for a run, I will definitely need a rest to stop and catch my breath. Does this apply to our brains as well?

Duncan - Even where we can improve something by practicing it, this doesn’t mean that we no longer require breaks. Demanding cognitive activities can be tiring. Forcing yourself to continue is unlikely to be optimal and regular breaks are necessary when performing demanding tasks, even when we’re highly practiced.

Izzie - In that case, I’ll go pop the kettle on. And if you’re taking any exams at the moment you should probably do the same.

Duncan - We know that when revising it’s really important to space revision out. Frequent bursts of revision are much more effective than the same amount of revision in one long block. This is sometimes called the spaced practice effect. This is because each time your revisit information you strengthen the corresponding memory traces. So, the more times you actively retrieve the information afresh, the more durable those memories become.

Izzie - So, after all this training, can our brain automatically adapt to take on any task?

Duncan - Whether these benefits will travel to other mental activities that we haven’t practiced is highly controversial. There isn’t much compelling evidence for these generalised benefits of mental practice.


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