Do you ever feel spacey, distracted, and worn down toward the end of a long work-related task – especially if that task is entirely a mental one? For over a century, psychologists have been trying to determine whether mental fatigue is fundamentally similar to physical fatigue or whether it is governed by different processes.
Some researchers have argued that exerting mental effort depletes a limited supply of energy – the same way physical exertion fatigues muscles. The brain consumes energy in the form of glucose, which can run low.
Other researchers see mental fatigue as more of a psychological phenomenon. Mind-wandering means the current mental effort is not being sufficiently rewarded – or opportunities to do other, more enjoyable activities are being lost.
