An elephant never forgets the sound of a hammer: Task difficulty and multimodal search.

摘要

How is attention divided in the human brain? What qualities of a task promote attentional division, and is there a point at which division hinders performance? Thus far, research has just examined limited situations in which multimodal stimuli are used. Tasks utilizing the pairing of visual and auditory stimuli have shown that the addition of auditory information does not inhibit performance (Kobus et al., 1986). Some research suggests that certain types of sound can enhance performance (Chen & Spence, 2011). Also, there was facilitation of visual search performance as auditory information that was unrelated to the task was added (Ngo & Spence, 2012). There may be other situations in which performance differs depending on task demands. To further investigate this, our studies consisted of a visual search task of six Snodgrass objects (Snodgrass & Vanderwart, 1980) paired simultaneously with an auditory stimulus that was either congruent or incongruent with the visual target. In three experiments, task difficulty was manipulated by varying the search category on each trial and the clarity of the image. Participants searched for visual objects that were either from the category a??ANIMALa?? or a??HOUSEHOLD ITEM.a?? As an assessment of accuracy they indicated where the target was on the screen. Generally, in all experiments, the pairing of an incongruent target and sound did not significantly impact reaction time and accuracy performance when the target category was more concrete, i.e. a??ANIMAL.a?? However, visual target and sound incongruency only impacted performance when the target type was not as well defined semantically, i.e. a??HOUSEHOLD ITEMa??. This result was sustained even when the difficulty of the visual task was enhanced by degrading the screen with an overlay of a??snowa??. Our results support that deficits in performance are more reliant on the semantic components of a task and the level of task difficulty.