According to a study published by the Association for Psychological Science, people are able to make better decisions when they control their bladder. Based on a science experiment conducted by Mirjam Tuk of the University of Twente in the Netherlands, people who drank 5 cups of water had more self control, and therefore made better decisions than those who drank only two sips of water.
In the experiment conducted by Tuk, participants answered eight questions after 40 minutes of water intake, explains APS. All the questions pertained to making a choice between receiving an immediate but small reward, or a larger reward but at a later time. For example, they were asked to choose between receiving $10 today or $20 in a week. It was observed that those people with a full bladder tended to choose the larger reward at a later time, while the others leaned toward choosing the smaller reward at an immediate date. The results of the experiment suggested that self control in one area such as the bladder might lead to the person exercising self control in other areas as well, leading to a decision of waiting for a longer period for a larger reward.
From a theoretical point of view, the results of this experiment surprised many psychologists, as they were contrary to the theory of "ego depletion," notes APS. The theory of ego depletion holds that when the brain exerts self control over one area, such as the bladder, it is then too tired to exercise self control over any other area. Therefore, the participants with a full bladder should have picked the immediate reward. Tuk says that it seems to work a different way, possibly because holding the bladder is an inbuilt natural process.