Dual-task studies on the capacity limits of perceptual attention and working memory.
Fougnie, Daryl Lawrence
We are only able to maintain a limited number of objects in working memory and can only attend to a limited number of perceptual representations. Do these limits stem from a single, undifferentiated source of capacity, or do capacity limits differ by task and by modality? The current studies explored the degree to which capacity limits for working memory (Chapter 2) and attention (Chapter 3) are domain-specific or domain-independent. Using a dual-task paradigm I found no evidence of interference between auditory and visuospatial working memory tasks, suggesting domain-specific sources of working memory capacity. In contrast, significant interference was found between auditory and visual attentive tracking tasks, and this interference was load-dependent. A comparison with a second study that paired two visual attention tasks suggested that our attentional capacity is constrained by both domain-general and domain-specific sources. These results further argue that attention and working memory are mediated by distinct processes and suggest that only attention is limited by domain-general sources.