You may or may not have heard of decision fatigue, but you have no doubt felt it. Decision fatigue refers to the exhaustion we feel after making so many large and small decisions over the course of the day.
Those in positions which involve more decision-making are of course more prone to this phenomenon. A 2011 study found that judges were likely to deliver harsher rulings later in the day.
But decision fatigue impacts everyone. Think about how many decisions you make every day. What to wear, what to eat for breakfast, how you want your coffee, whether to stop for gas, how to greet your coworkers, which task to start first, what language to use in an email... The list goes on.
These decisions add up. We make thousands of decisions every single day. But we don't have an infinite amount of energy and willpower with which to make these decisions.
The New York Times published a wonderfully comprehensive article about decision fatigue, which includes links to studies demonstrating the finite nature of willpower.
At some point, we simply run out of mental energy. What happens then?
Burnout. When your stores of mental stamina are exhausted, you're likely to crash, and you're likely to make poor decisions. You may not have the willpower to resist temptation, like that plate of chocolate chip cookies on the counter. Or to say no to a friend or salesperson.
Mental exhaustion and burnout can have all kinds of effects, and none of them are good.