This year's IgNobel prize in Medicine goes to TWO studies, one of which I knew I would enjoy based entirely on the running title. The running title is, when you read a scientific paper, the few words at the top or bottom to remind you of which paper it is exactly that you're reading (useful mostly when you're flipping through a journal, but also with surprising uses in remembering what exactly you're supposed to be learning about when you're ten pages into a huge review). The running title of this one is "inhibitory spillover". And it's about urine. Spillover. LOL.

Sorry, been a long few days. :)

Tuk and Twente. "Inhibitory spillover: increased urination urgency facilitates impulse control in unrelated domains" Psychological Science, 2011.


We have to make a lot of choices in life. We have to decide whether we want to go out to dinner now, or save the money to replace the old clunky car a few months down the road. We have to decide whether to eat the healthy choice of food now, or worry about our waistlines later. These are examples of something called self-control, where we control our impulses in order to meet a more long-term goal (or maybe an immediate goal that, though virtuous, is not nearly as appealing).

A lot of studies have gone in to what impacts self-control. Normally these studies focus on things that make you give in to the spur of the moment. Things like sexual desire or hunger, these are things that tend to make people make the more impulsive choices. It's a visceral bodily sensation that controls the way you behave in other domains, domains not actually related to sexual desire or hunger (for example, you may spend more money or buy things you don't really want). But it's a little harder to study things that give us MORE self-control. What kind of visceral sensation would make us BETTER at self-control?

Well, I don't know. Do you need to pee? Does it make you more risky in your behavior? Or does it actually make you have a little bit better self-control than you might otherwise? After all, if you gotta go and you're holding it, maybe that makes you better at "holding it" in other behavioral domains.

To test this, the authors took a bunch of college students, paid them (thank goodness), and gave them a behavioral task. The task is the stroop task, which is a cognitive test which requires inhibition of a response. You're given a word. First you have to match it with the right word in the corner. That's super easy, it's your dominant response. Then you're given the word, and told to match, not the word, but COLOR the word is. This is harder and involves inhibiting your dominant response in favor of another one.

Then they had the students take the test again. But first, they made them drink water. Some were given 5 cups of water and told to take a small sip from each cup. The rest were given 5 cups and told to drink it ALL DOWN. Thy then waited 45 minutes, and had them take the Stroop test. Needless to say, no bathroom breaks. They asked them how urgently they needed to pee, and then looked at how well they did in a Stroop test, and in a test where they had to wait for a large reward, or accept a small one immediately.

It turned out that the worse you had to pee, the better you did on the tests, doing better on the Stroop test and choosing to wait for larger rewards. The act of inhibiting your bladder from letting it all leak appears to extend to other behaviors as well. So it turns out that when you have to pee, you are MORE patient rather than less! In fact, further studies showed that just being TOLD about needing to pee, increased the participants need to pee AND increased their self-control! It seems that visceral cues like needing to pee can influence our behavior in other domains. When you hold it physically, you may be able to hold it better behaviorally. And you can get the effect just by HEARING about other people peeing.

So, do you need to pee yet? How about now? How about NOW?!

Now go put some money in your savings. It's good for you. :)

Now the SECOND paper that won the IgNobel for medicine is ALSO on urine physiology, and one where they found findings that were...somewhat opposite to the first one. But not really. I had a great time talking to these guys at the IgNobel after party (hi guys!) and one of them let me know that he successfully underwent the water volume loading I will talk about in their task for THREE HOURS. I think he's some kind of magical being. You'll see.

Lewis et al. "The effect of acute increase in urge to void on cognitive function in healthy adults." Neurology and Urodynamics, 2011.

This study was actually not ORIGINALLY about needing to pee, but the results of it turned out so interesting...well it became about pee. The coolest science is done this way. The original purpose of the study was to examine various cognitive tests that the authors were developing to detect early-onset Alzheimer's. You want to give these tests to people BEFORE they show symptoms, but many cognitive tests are subject to practice improvement, which biases your results. So the authors wanted to try a new test and see if they got around the practice problem. They wanted to work with various levels of distraction, and well...needing to pee is pretty distracting.

They had eight participants drink 250mL of water...every 15 minutes. Until they COULDN'T ANYMORE. This is a lot more water than in the previous study, and resulted in a much bigger urge to pee than the previous study got. While they students had to pee, and then really had to pee, and then really PAINFULLY had to pee...and then right after they finally let them go, the authors administered cognitive tests. By the end, the participants had consumed nearly 2 and a half LITERS of water.

...and in the cognitive tests the participants did steadily WORSE. The worse they had to pee, the worse their scores got, until they were on a par with someone who had stayed up for 24 hours (or who was drunk at a bar). And by that point, they REALLY had to pee. They then allowed the participants to finally lake a well-deserved leak, and had them back in. The instant they got the opportunity to pee, their scores returned to normal.

The authors talk in the discussion about the interactions between the need to micturate (that's pee) and cognitive impairment and the periaqueductal grey matter, but I also have to wonder if the participants were merely just REALLY distracted, if it was just a matter of something more urgent impairing their attention.

Now, you might be thinking "wait, the first study said that needing to pee INCREASES your ability to think (or at least your self-control), and the second study makes it WORSE. What gives?" The reality is that these two studies are not inconsistent. The devil is the details, and the details are in just HOW MUCH you have to pee. In the first study, the participants only had to drink a total of 5 cups of water, while in the second study you're looking at as much as 2.5 LITERS of water. It appears that when you only have to pee a LITTLE, it's nothing urgent, your ability to exercise your self-control may be better. On the other hand, if you're about to wet yourself...well I don't know about you but I bet my SAT scores would drop significantly. With urine and cognitive impairment, it looks like a matter of magnitude.