Pupil's Bigger Pupils

Apparently we spend a great deal of our day with thoughts that are unrelated to the task that we are performing. Of course, this gets worse when we are doing something boring or of little importance to us.

Once our psychologist/neuroscience friends get going, they can set up tasks in the lab that would bore the socks off most of us. Smallwood et al set 9 healthy 20-year old guys to watching computer monitors flashing numbers at them every couple of seconds for about 20 minutes (1). Interspersed with the numbers were X’s and the guys had to hit a button so their reaction times could be measured.

At the same time their pupils were monitored as an indicator of the level of Norepinephrine sloshing about in their brains. Bigger pupils correspond to larger amounts apparently. Now norepinephrine levels affect cognition and decision-making – low levels have been indicated as being connected to ADHD.

After their rather boring 20 minutes, the participants were grilled about their inner thoughts and their dilated pupils corresponded to their having more task unrelated thoughts, that is they were starting to daydream. Their slower reaction times also correlated with their larger pupil diameters and hence their daydreaming.

Of course there is a theory – an Adaptive Gain Theory, which suggests that at higher levels of norepinephrine the attention becomes defocused so that alternative possibilities to the current goal may be explored.  This apparently is  a good thing for both non-human and human primates as they can become mentally disengaged from something boring and easy so as to get some new bright idea.

Perhaps in the future, when we have more and more teaching at our computer screens, the face-time cameras will be monitoring our pupil’s pupils to make sure that they don’t start to dilate and bring them back to reality as soon as they do. Of course, if they nod off, we’re stuck.

  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0033706

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