"Need to void and attentional process interrelationships." by a french group, first author Marylène Jousse. They studied how your when you have to 'go', your attention and cognition may be affected.
There is some really cool stuff in this paper. First, there is apparently a device called an 'Urgeomotor". And a scale called the "Urogenital Distress Inventory score". And a measurement process called "uroflowmetry", a type of Urodynamic testing. And theories about the neural circuitry involved in monitoring and deferring the need to go.
To run this experiment, they had participants drink 500 ml of water, and then perform some cognitive tasks, including the PEBL Continuous Performance Test. No joke--this is referred to as a 'go/no-go task'. They tested them twice, to see what happens as the water passes into the bladder and the 'urge' increases.
Results showed that for the CPT, the second time (with a greater 'urge'), participants were faster and less accurate--a speed-accuracy trade-off. It is not clear whether they are actually worse (i.e., some sort of attentional cost), but they start speeding up and their error rate (mostly more errors of commission) increase. One way to assess this is to use adjusted RT, which I've described here. This essentially computes a 'throughput' measure--how many correct responses can be made in a fixed period of time.
So, by computing their actual RT and accuracies in the two conditions (421/.977 vs 398/.969), we can derive 'adjusted' RT scores of 430 and 410 ms. One way to interpret this is that participants actually got better when they had a 'strong need to void'. This may partly stem from practice effects, but it also is a type of incentive--the faster they complete the task, the faster they can go to the bathroom. Without this pressure, they were lackadaisical and so it gave them a real incentive to perform.
I think research like this is pretty interesting. It is important to remember that many people have urological disorders and conditions that impact their ability to function, and it would be important to establish whether the medications people take to help them have cognitive side effects. But this is tricky to know this because the state of having to 'void' can essentially make you faster at tasks, appearing to be better.