Making fewer decisions equals more happiness. Most people believe that having a lot of options will make them happier. Science says the opposite. It's mentally exhausting to have to choose from too many options.

The act of making many decisions over the course of a day can lead to what is known as "decision fatigue." Even decisions that may seem small and trivial can add up, gradually sapping our energy and willpower to make good choices going forward.

Scientists believe that decision fatigue happens because the act of making choices calls upon the same part of the brain that is used for self-control and discipline. So when our decision-making band of the brain gets worn out, so does our ability to exert self-control.

As a result, the more choices we face during the day, the harder it becomes to exercise proper willpower and consider options carefully. We are more likely to give in to urges and temptations, seek out immediate gratification, and act on impulse.

Studies have shown many signs of decision fatigue. For example, judges in court often grant a favorable ruling early in the day or right after a food break, and then become much less generous immediately preceding the next break.

This shows how the act of decision making causes a detectable drain on the judges' limited energy and bandwidth for disciplined thinking. Shoppers also tend to gravitate toward the easiest and most accessible products towards the end of a long day of shopping—potentially making poorer choices just to avoid contemplating additional options.

There are ways to reduce decision fatigue. First, avoid unnecessary small choices during the day, like deciding what to wear or eat. Routines and habits can eliminate such low-impact decisions.

For more important choices, you should strive to make them early in the day or right after a break when possible, while willpower and self-control levels are relatively high. Taking breaks to recharge is also critical.

Finally—even just becoming aware of how decision fatigue works may prompt people to be more wary of impulsive thinking and reckless decisions as the day goes on.