No abstract

We investigated participants’ task set preparation by measuring changes in pupil diameter during a blank interval as they prepared for an easy (i.e., prosaccade) or difficult (i.e., antisaccade) trial. We used occasional thought probes to gauge “on-task” thoughts versus mind wandering. In both studies, participants’ pupil diameters were larger when anticipating an antisaccade, relative to a prosaccade, trial. In contrast, their self-reported mind wandering depended upon whether the thought probes occurred after their target detection response (Experiment 1) or occurred in lieu of target detection (Experiment 2). In the latter case, self-reported mind wandering echoed the pupil diameter changes in demonstrating greater off-task behavior when preparing for a prosaccade trial. More important, trial type effects in pupil diameter emerged only when participants reported being “on-task,” but disappeared during periods of mind wandering. These results demonstrate that changes in pupil diameter reflect the degree of preparatory control exerted for an upcoming trial, but only when attention is actively focused on the upcoming task.

In two experiments we demonstrate that much larger practice effects occur in a backward masking paradigm where patterned masks are used than in similar visual processing paradigms, such as lateral masking and whole report. In additional experiments we examine four possible explanations for the large practice effects: increased familiarity with the paradigm in general, learning about the targets, learning about the masks, and enhanced sensory processing. Because of failure to observe similar practice effects in related paradigms not involving backward masking and because of the sustained nature of the improvement, we reject the first explanation as a source of practice effect. Experiment 3 allowed us to reject target learning as a source of improvement as well; target sets were switched at the end of training, but no decrement in performance was observed. In Experiment 4, mask sets were switched at the end of training, revealing a significant decrement in performance. Learning about the specific masks, then, does contribute to the observed improvement. However, it is responsible for only about one third of the overall improvement in performance. The final experiment provides evidence that the residual improvement is due to enhanced sensory processing. In that experiment, training on backward masking led to a lowered threshold in a two-flash paradigm but not to a significant change in whole-report performance.

Eye blink measures have been shown to be diagnostic in detecting deception regarding past acts. Here we examined—across two experiments with increasing degrees of ecological validity—whether changes in eye blinking can be used to determine false intent regarding future actions. In both experiments, half of the participants engaged in a mock crime and then transported an explosive device with the intent of delivering it to a “contact” that would use it to cause a disturbance. Eye blinking was measured for all participants when presented with three types of questions: relevant to intent to transport an explosive device, relevant to intent to engage in an unrelated illegal act, and neutral questions. Experiment 1 involved standing participants watching a video interviewer with audio presented ambiently. Experiment 2 involved standing participants questioned by a live interviewer. Across both experiments, changes in blink count during and immediately following individual questions, total number of blinks, and maximum blink time length differentiated those with false intent from truthful intent participants. In response to questions relevant to intent to deliver an explosive device vs. questions relevant to intent to deliver illegal drugs, those with false intent showed a suppression of blinking during the questions when compared to the 10 s period after the end of the questions, a lower number of blinks, and shorter maximum blink duration. The results are discussed in relation to detecting deception about past activities as well as to the similarities and differences to detecting false intent as described by prospective memory and arousal.

Attention control is often examined behaviorally by measuring task performance and self-reported mind wandering. However, recent studies have also used pupillometry to measure task engagement versus task disengagement/mind wandering. In the current study, we investigated participants' ability to engage versus relax attention control in anticipation of hard (antisaccade) versus easy (prosaccade) trials within a saccade task, creating a "Cue-Evoked" Pupillary Response (CEPR). Participants completed the Automated OSPAN as a measure of working memory capacity (WMC) followed by a saccade task with a constant 5,000 ms delay between cue and stimulus. Occasional thought probes were included to gauge on-versus off-task attentional state. Consistent with recent findings (