Orienting and schizophrenia: Stimulus significance, attention, and distraction in a signaled reaction time task.

Abstract

Interpreting the orienting response as a call for controlled processing resources, we tested the hypothesis that poor performance among schizophrenics is associated with less orienting to task-relevant stimuli and more orienting to task-irrelevant stimuli. Thirty-two schizophrenics and 32 age-and sexmatched controls were exposed to a signaled reaction time task in which one tone was followed by an imperative noise stimulus and a different tone signaled nothing. During one phase of the experiment, distracting visual stimuli were presented both between and during reaction time trials. Orienting was assessed by measurement of skin conductance, heart rate, and finger pulse volume responses. The controls differentiated between the signal and nonsignal tones in all measures and showed rapid habituation to the distracting visual stimuli. The schizophrenics showed very slow reaction times, less overall responding than the control group, and very limited differential responses to signal and nonsignal stimuli. For the responses to visual distractors, however, the schizophrenics showed significantly slower habituation than the controls, confirming their inefficient orienting style. 326This document is copyrighted by the American Psychological Association or one of its allied publishers.This article is intended solely for the personal use of the individual user and is not to be disseminated broadly.

The neuropsychology of schizophrenia

“…In contrast, in the typical orienting and habituation paradigm, only one stimulus is presented repeatedly and no task is required. In support of the importance of this difference, Ohman et al (1986) tested schizophrenic patients In a modified orienting and habituation paradigm that involved presentation of relevant and distracting stimuli. Ohman et al found that the patients oriented less than normal to task-relevant stimuli, but more than normal to the distracting stimuli.…”

Increased Distractibility in Schizotypy: Independent of Individual Differences in Working Memory Capacity?

“…Vernon et al (2005) propose that this neural model becomes vulnerable to degradation through impoverished updating or rehearsal processes so that it is no longer a viable match for the incoming auditory stimulus. As a consequence, an OR will occur and habituation of the OR will diminish or fail (Öhman, Nordby, & d'Elia, 1986). While our experiment did not examine habituation directly, it is important to address whether particular schizotypal symptoms are associated with a failure to suppress the OR, in addition to habituating the OR.…”

The neuropsychology of schizophrenia: Act 3

“…However, the issue is further complicated by Lubow's important distinction between habituation of unconditioned specific responses to the CS, and habituation of the orienting response (OR). It is the latter that has been most frequently investigated in schizophrenics (e.g., Ohman et al 1986). There is some evidence of a relationship between OR habituation and LI (Kaye & Pearce 1987), although a context change insufficient to dishabituate the OR nevertheless interferes with LI (Hall & Channel 1985).…”