Release from proactive interference: Determinants of performance and neuropsychological correlates

Abstract

The Wickens (1970) modification of the Brown-Peterson short-term memory task has been used to investigate release from proactive interference (PI) in a number of memory-impaired groups. It has been suggested that failure to release from PI is observed only in patients with compromise of both memory and 'frontal-lobe' functions. The present study examined performance on this paradigm in patients with schizophrenia (SC), a neuropsychiatric disorder which typically includes both frontal and mnemonic impairments. Patients with SC were found to exhibit significantly less release from PI than normal controls. It was determined through correlational analyses that average Trial 1 performance on this task could predict performance on all subsequent trials, indicating that 'release' from PI may measure the same psychological process as the Brown-Peterson task, which does not include a release condition. Trial 1 performance in the SC group was correlated with a wide range of neuropsychological measures, but after the effect of full scale IQ was partialled out, only correlations with measures of memory and measures of frontal-lobe function remained significant. The results support previous formulations of the neuropsychological concomitants of release from PI, but suggest that failure to release on this paradigm may be secondary to a significant compromise of the ability to perform the Brown-Peterson task. It is proposed that the experimental design constraints necessary to elicit a failure to release from PI in any patient group may limit the utility of this measure, and that Brown-Peterson performance may be a more reliable index of the neuropsychological functions involved.