We’ve all experienced the fading of our ability to concentrate when we’ve been focused on a task for too long. The dominant theory of why this should be so has been around for half a century, and describes attention as a limited resource that gets ‘used up’. Well, attention is assuredly a limited resource in the sense that you only have so much of it to apply. But is it limited in the sense of being used up and needing to refresh? A new study indicates that it isn’t.

The researchers make what strikes me as a cogent argument: attention is an endless resource; we are always paying attention to something. The problem is our ability to maintain attention on a single task without respite. Articulated like this, we are immediately struck by the parallel with perception. Any smell, touch, sight, sound, that remains constant eventually stops registering with us. We become habituated to it. Is that what’s happening with attention? Is it a form of habituation?

In an experimental study, 84 volunteers were tested on their ability to focus on a repetitive computerized task for 50 minutes under various conditions: one group had no breaks or distractions; two groups memorized four digits beforehand and were told to respond if they saw them on the screen during the task (but only one group were shown them during the task); one group were shown the digits but told to ignore them if they saw them.

As expected, performance declined significantly over the course of the task for most participants — with the exception of those who were twice shown the memorized digits and had to respond to them. That was all it took, a very brief break in the task, and their focus was maintained.

The finding suggests that prolonged attention to a single task actually hinders performance, but briefly deactivating and reactivating your goals is all you need to stay focused.