Data from: Pupil diameter tracks lapses of attention

Our ability to sustain attention for prolonged periods of time is limited.
Studies on the relationship between lapses of attention and
psychophysiological markers of attentional state, such as pupil diameter,
have yielded contradicting results. Here, we investigated the relationship
between tonic fluctuations in pupil diameter and performance on a
demanding sustained attention task. We found robust linear relationships
between baseline pupil diameter and several measures of task performance,
suggesting that attentional lapses tended to occur when pupil diameter was
small. However, these observations were primarily driven by the joint
effects of time-on-task on baseline pupil diameter and task performance.
The linear relationships disappeared when we statistically controlled for
time-on-task effects and were replaced by consistent inverted U-shaped
relationships between baseline pupil diameter and each of the task
performance measures, such that most false alarms and the longest and most
variable response times occurred when pupil diameter was both relatively
small and large. Finally, we observed strong linear relationships between
the temporal derivative of pupil diameter and task performance measures,
which were largely independent of time-on-task. Our results help to
reconcile contradicting findings in the literature on pupil-linked changes
in attentional state, and are consistent with the adaptive gain theory of
locus coeruleus-norepinephrine function. Moreover, they suggest that the
derivative of baseline pupil diameter is a potentially useful
psychophysiological marker that could be used in the on-line prediction
and prevention of attentional lapses.