This self-directed computerized task requires the subject to search for hidden tokens one at a time within sets of four to eight randomly positioned boxes. Tokens are hidden only once in each box. Working memory skills are tapped as the subject, while searching, must hold in working memory the locations already checked and, as tokens are found, they must remember and update the information about the locations of the found tokens (Elliott et al., 1997). In functional imaging studies, this specific task reliably activates dorsolateral prefrontal cortex (Owen, 1997a, 1997b; Owen, Doyon, Petrides, & Evans, 1996). The dependent variable for the Spatial Working Memory task was the between-search errors score.
