Abstract
Past research on inattentional blindness has uncovered few reliable individual difference measures that successfully predict failures to detect an unexpected event. Most notably, no correlation exists between primary task performance and inattentional blindness (Simons & Jensen, 2009). This is perplexing as better primary task performance is typically associated with increased effort, which in turn is associated with fewer spare attentional resources to process the unexpected event. Our experiment utilized a psychophysiological measure of effort (pupillary response) to determine whether effort devoted to the primary task is related to inattentional blindness, and whether accuracy is a valid measure of effort in a task such as multiple object tracking. A paradigm similar to Simons and Jensen (2009) was used. Observers’ eye movements were recorded as they tracked white T’s among white and black distractor letters. Tracking load was manipulated to assess pupillary response as a function of effort devoted to the task. Namely, each block alternated between four targets and one target, with the final block containing the critical trial in which the unexpected event (i.e. a black cross) occurred. The pupillary response of those who noticed the unexpected event was compared to those who did not notice. Results showed that tracking load significantly influenced pupillary response (9% increase in pupil size under high load), t(100) = 18.95, p<.001. However, the pupillary response of those who noticed the unexpected event did not significantly differ from those who did not, t(99) = 1.55, p= .12. While these tentative results suggest that effort measured by pupillary response is unrelated to inattentional blindness, a follow-up study is being conducted to replicate and further explore these findings.
Meeting abstract presented at VSS 2012