Selective attention is a process which requires that an individual devotes attention to a task-relevant stimulus and processes it, while ignoring a distracting-irrelevant stimulus. The ability to selectively attend and respond effectively to relevant stimuli is essential for adaptive behavior and normal cognitive functioning, since, according to capacity approaches (e.g., Kahneman, 1973; Navon & Gopher, 1979), attention exists in limited amounts and might be allocated to irrelevant as well as relevant information (e.g., Gopher, 1992).
That normal selective attention is essential for adaptive behavior is supported by the literature which shows a relationship between psychopathology and the impairment of selective attentional processes. The most prominent example of such a relationship is the attentional deficit of schizophrenics and “normal” schizotypals. Studies have shown that, as compared to normal individuals, schizophrenics and schizotypals are distracted by irrelevant stimuli (see below). In addition, there is evidence that individuals characterized by high levels of anxiety also are distracted by irrelevant stimuli, although most studies suggest that anxiety leads to an attentional bias only for irrelevant threat-related stimuli.
Surprisingly, despite the similarity of selective attention impairments in schizophrenia/schizotypy and anxiety, there are hardly any studies that have tested whether the anxiety that characterizes schizophrenia/schizotypy accounts for (even only partially) the difficulties schizophrenics/schizotypals have in ignoring irrelevant information.
This chapter will present data about selective attentional dysfunction in groups rated low and high on self-report anxiety and schizotypy scales and in situations that elicit anxiety (stress).