The impact of secondary tasks on multi-tasking in a virtual environment.

One experiment is described that examined the possible involvement of working memory in the Virtual Errands Test (McGeorge et al. (2001). Using virtual environments in the assessment of executive dysfunction. Presence, 10, 375-383), which requires participants to complete errands within a virtual environment, presented on a computer screen. Time was limited, therefore participants had to swap between tasks (multi-task) efficiently to complete the errands. Forty-two undergraduates participated, all attempting the test twice. On one of these occasions they were asked to perform a concurrent task throughout (order of single and dual-task conditions was counterbalanced). The type of secondary task was manipulated between groups. Twenty-one participants were asked to randomly generate months of the year aloud in the dual-task condition, while another 21 were asked to suppress articulation by repeating the word "December". An overall dual-task effect on the Virtual Errands Test was observed, although this was qualified by an interaction with the order of single and dual-task conditions. Analysis of the secondary task data showed a drop in performance (relative to baseline) under dual-task conditions, and that drop was greater for the random generation group than the articulatory suppression group. These data are interpreted as suggesting that the central executive and phonological loop components of working memory are implicated in this test of multi-tasking.