Abstract
Numerous studies have found deficits in visual attention and working memory capacity in schizophrenia patients (SZ) in comparison to healthy controls (HC; e.g., Nuechterlein & Dawson, 1984; Park & Holzman, 1992). For example, Gold et al. (2003) found that SZ have reduced VWM capacity, particularly when presented with larger set size arrays. Moreover, in healthy controls, we have recently shown that an individual's memory capacity strongly predicts his or her selective attention ability (Vogel et al, 2005). Here, we used a battery of visual memory and attention tasks to characterize the distribution of individual differences in performance in schizophrenia-spectrum individuals. One goal of the study was to examine whether the predictive relationship between working memory capacity and attention tasks is preserved within the SZ population. Specifically, we recorded behavioral and electrophysiological data while subjects performed a change detection task, as well as several attention tasks (e.g., attentional filtering; multiple object tracking; and task switching). Our preliminary results indicate that we have replicated Gold et al.'s findings that SZ subjects have lower memory capacity than HC. Additionally, our data thus far suggests that the direct relationship observed between attention and working memory capacity in HC does not persist in SZ subjects. That is, low capacity HC tend to have deficits in attentional filtering, whereas SZ tended to have normal filtering ability despite low memory capacity. Together, these results suggest that examining the relationship between various cognitive processes can provide some predictive ability for functional outcome in SZ. Thus, neurocognitive markers identified with adequate sensitivity and specificity may allow for predictive validity for the later development of schizophrenia.