Abstract
In everyday life we must often shift our attention between tasks that require processing in different sensory modalities, yet the vast majority of experimental work on task switching has focused only on shifting attention between visual tasks. We conducted a set of experiments that required participants to perform a visual task (identifying a shape presented on a computer screen) and an auditory task (identifying a letter presented through headphones). Participants were presented with a pretrial cue instructing them to perform either the visual task, the auditory task, or both tasks on the upcoming trial. We observed significant switch costs for both modalities; that is, trials in which participants were required to switch attention between the visual and auditory tasks yielded longer RTs than trials in which participants performed the same task on consecutive trials. While this pattern is similar to that typically observed in studies requiring participants to switch attention between only visual tasks, we also varied the cue-target interval (CTI) and found that the preparatory cues were used differently in each modality. Switch costs decreased as CTI lengthened in the visual modality but did not do so in the auditory modality, suggesting that visual task cues trigger endogenous, goal-driven processes, while auditory task cues alternatively may trigger an alerting or "warning" effect. Converging evidence for this finding that auditory and visual task cues activate different preparatory processes was also found in the dual task conditions, where participants had to respond to both the auditory and visual targets on the same trial. These results suggest that auditory and visual cues evoke different control processes, a finding that has important implications for understanding how attention is controlled in dynamic, information-rich environments where attention must be shifted and/or divided between multiple tasks that require processing in different sensory modalities.
Meeting abstract presented at VSS 2012