Conventional wisdom holds that one should never go grocery shopping on an empty stomach. Now, if new research is to be believed, one should never make a big decision on an empty bladder, either. Dutch researchers have shown that controlling the bladder triggers self-restraint in other areas, helping people make better decisions. Here's a brief guide to the counterintuitive finding:

Wait, why do full bladders lead to good decisions?
When people resist the urge to urinate, they activate regions in the brain that help to resist other urges, according to a paper published in the journal Psychological Science by researchers from the University of Twente in the Netherlands. That helps them keep a lid on desire — to buy an unnecessarily expensive item, for example. "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," says study leader Mirjam Tuk, as quoted by The Telegraph.

Do other studies back that up?
No. The discovery runs counter to previous research, which showed that people who are forced to show restraint in one area find it difficult to exert self-control in another.

So how did this study work?
Tuk had subjects either drink five full cups of water (750 ml each) or take five small sips. She waited 40 minutes — the time it takes liquid to reach the bladder — and then asked the participants to make eight different choices in which they could either receive a small, immediate reward, or a larger one at some point in the future. The subjects who drank the larger amount of water were more likely than their blissfully unburdened counterparts to hold out for the larger reward, which the researchers deemed a "better" decision.

Is there a substitute for drinking all those liquids?
For those dreaming of that next unaffordable gadget, the researchers found that simply thinking about urinating produced similar effects to the feeling of a full bladder.

Sources: Telegraph, Psychological Science