Abstract
Arousal is an important modulator of diverse behavior, and has been shown to alter performance in various tasks, most notably those requiring a high level of cognitive control. Less is known about the effects of arousal on feature selectivity in visual attention. Both recent and classical theories have hypothesized that increased arousal narrows the scope of attention, resulting in facilitated processing of physically, or behaviorally, salient stimuli. We used 4 different arousal manipulations, in otherwise identical experiments, to test the effects of arousal upon feature selectivity. Observers were presented with a red target letter in brief post-masked displays. Distractor letters (blue or yellow) were presented alongside the target on some trials, to vary the degree of feature selectivity required of observers. Arousal was manipulated using loud white noise, emotionally arousing images, an alerting tone (300 ms tone-to-target SOA), or an accessory stimulus tone (30 ms SOA). Race models were fitted to the results of each experiment to assess which components of attention were affected by arousal. Our results demonstrate that 1) white noise did not affect attention, while 2) phasic arousal by emotional image presentation did increase the overall processing capacity of observers, without any benefits to selectivity. 3) The accessory stimulus had a large increase in processing capacity, but reduced feature selectivity. 4) Conversely, when the alerting tone was presented there was no change in overall processing capacity, but selectivity was facilitated to an extent that rendered the distractors functionally inept. Our models suggest that the brief presence of a loud tone triggers an immediate and transient increase in indiscriminate processing, followed by a period of almost perfect selectivity, and highlight the importance of constraining experimental designs to reveal the cognitive processes that are affected by arousal.
Meeting abstract presented at VSS 2016