Photo remixed from an original by Alan Cleaver
How does this work? According to Science Daily, sexual excitement, hunger and thirst are all triggers that can make people actually want other things, even if they seem unrelated.
[Mirjam]Tuk came up with the idea for the study while attending a long lecture. In an effort to stay alert, she drank several cups of coffee. By the end of the talk, she says, "All the coffee had reached my bladder. And that raised the question: What happens when people experience higher levels of bladder control?" ... In one experiment, participants either drank five cups of water (about 750 milliliters), or took small sips of water from five separate cups. Then, after about 40 minutes — the amount of time it takes for water to reach the bladder — the researchers assessed participants' self-control. Participants were asked to make eight choices; each was between receiving a small, but immediate, reward and a larger, but delayed, reward. For example, they could choose to receive either $US16 tomorrow or $US30 in 35 days.
The results? More often than not the people will full bladders held out for the larger reward the next day — clearly the smarter choice. Next time you need to make an important decision, try holding out until your bladder's full. It might help.