Anyone considering an expensive purchase might do well to drink a bottle of water first, scientists concluded after finding that people with full bladders make wiser decisions.
Researchers discovered the brain’s self-control mechanism provides restraint in all areas at once.
They found people with a full bladder were able to better control and “hold off” making important, or expensive, decisions, leading to better judgement.
Psychologists from the University of Twente in the Netherlands linked bladder control to the same part of the brain that activates feelings of desire and reward.
The study, published in the journal Psychological Science, also concluded that just thinking about words related to urination triggered the same effect.
Their findings contradict previous research which found people who are forced to “restrain themselves” put more pressure on their brain and found it difficult exerting self-control.
Dr Mirjam Tuk, who led the study, said that the brain’s “control signals” were not task specific but result in an "unintentional increase" in control over other tasks.
"People are more able to control their impulses for short term pleasures and choose more often an option which is more beneficial in the long run,” she said.
"The brain area sending this signal, is activated not only for bladder control, but for all sorts of control.
"Controlling our impulsive desires for an immediate reward, in favour of a larger reward at a later date, is a similar type of response, originating from this same neurological area.
In her study, Dr Tuk asked volunteers to drink either five cups of water containing 750 millilitres or take small sips of water from five separate cups.
After 40 minutes, the estimated time water is thought to reach the bladder, researchers assessed participants' self-control.
They were asked to make eight choices ranging from small, and immediate, rewards to larger, but delayed, ones including choosing to receive either $16 (£10) tomorrow or $30 (£18) in 35 days.
They concluded that people with full bladders were better at holding out for the larger rewards later.
“You seem to make better decisions when you have a full bladder,” said Dr Tuk, whose study came about after sitting through a long lecture.
“Maybe you should drink a bottle of water before making a decision about your stock portfolio.
“Or perhaps stores that count on impulse buys should keep a bathroom available to customers, since they might be more willing to go for the television with a bigger screen when they have an empty bladder."