Pupillary responses on the visual backward masking task reflect general cognitive ability.

Cognitive processing efficiency requires both an ability to attend to task-relevant stimuli with quickness and accuracy, also while filtering distracting or task-irrelevant stimuli. This study investigated cognitive processing efficiency by using pupillary responses as an index of attentional allocation to relevant target and irrelevant masks on a visual backward masking task. The relationship between attentional allocation on this task and general cognitive ability on the scholastic aptitude test (SAT) was examined in college students (n=67). A principle components analysis of the pupillary response waveform isolated a late component that appeared to index the attentional demands associated with processing masks on the backward masking task. This pupillary response index of wasteful resource allocation to the mask accounted for significant variance in SAT scores over and above that accounted for by socio-economic status and target detection accuracy scores. Consistent with the neural efficiency hypothesis, individuals who allocated more resources to processing irrelevant information performed more poorly on cognitive ability tests.