Abstract
Buetti and Lleras (2016) demonstrated that the level of engagement required by a cognitive task modulates the rate of oculomotor capture by task-irrelevant images. Specifically, oculomotor capture diminished from ~70% to ~40% when participants performed a series of easy mental math operations compared to a series of difficult mental math operations. An advantage of the task used by Buetti and Lleras is that the task did not constrain in any way visual attention: math operations were presented auditorily and the images that appeared on the display were the only visual events in the trial sequence (and were completely unrelated to the task). Buetti and Lleras suggested that when attention is required internally by a cognitive task there is an automatic tuning down of external sensory information. The goal of the present study was to seek a more direct measure of this reduction in visual sensitivity under different cognitive load conditions. Visual sensitivity was examined using the Octopus 900 visual perimeter taking advantage of the wide presentation field and the adaptive stair-casing. Sixty locations throughout the visual field were examined using 100 ms flashes of varying intensity. Participants completed the visual detection task under three conditions: 1) baseline (detection task only); 2) low load (series of simple mental math operations presented auditorily in addition to the detection task); 3) high load (series of more difficult mental math operations in addition to the detection task). The results showed the expected decrease in visual sensitivity as a function eccentricity as well as an additive effect of cognitive load. Interestingly, there was no significant interaction, suggesting that sensitivity throughout the visual field was equally affected. The results are discussed in relation to the literatures on the useful field of view and Inattentional Blindness, and a possible neural underlying mechanism is presented.
Meeting abstract presented at VSS 2018