The Processing of Stimulus Properties: Evidence for Dual-Task Integrality

Assessed the conditions under which dual-task integrality can be fostered by manipulating 4 factors likely to influence the integrality between tasks: intertask redundancy (ITD), the spatial proximity of primary and secondary task displays, the degree to which primary and secondary task displays constitute a single object, and the resource demands of the 2 tasks. The resource allocation policy was inferred from changes in the amplitude of the P300 component of the event-related brain potential. 12 university students participated in 3 experimental sessions in which they performed both single and dual tasks. The primary task was a pursuit step tracking task. The secondary tasks required Ss to discriminate between different intensities or different spatial positions of a stimulus. Task pairs that required the processing of different properties of the same object resulted in better performance than task pairs that required the processing of different objects. These same object-task pairs led to a positive relation between primary task difficulty and the resources allocated to secondary task stimuli. ITD and the physical proximity of task displays produced similar effects of reduced magnitude