Ever felt like your head is trying to tell you something after a long day's hard activity? Research suggests that the brain sends signals to your pain receptors when it's exhausted, which triggers you to start thinking that maybe it's time to down tools. However, if you're being rewarded for the effort, it's much easier to do so.
The research, published at PNAS, saw French scientists developing a task that tracked brain activity while performing a gripping task in exchange for a financial benefit proportional to how long they held grip. Neuroimaging showed a signal in the posterior insula -- the area of the brain involved with pain perception -- that intesified during activity and decreased when the subjects were at rest.
Work hurts, in other words, which isn't entirely new, but what the scientists found was that while the signal intensified if they simply made the task harder, as you'd expect, when they also upped the rewards, the level at which it accumulated was reduced and the speed with which it dissipated increased, as well as expanding the minimum and maximum levels of tolerance. What this means is that it's very likely that your brain actively works to maximise obvious benefit to itself, although not to a point where you're actually exhausted.
The research continues -- when doesn't it? -- but the practical takeaway from this is that while incentives can indeed make us work both harder and perhaps smarter, it's still sensible to take breaks from work at regular intervals. If you're being rewarded amply, you'll even find that you need lesser break periods.