Information Processing Deficit in Schizophrenia: A Frontal Lobe Sign?

To the Editor.—  In their article in the September 1988 issue of the Archives, Braff and Huey¹ demonstrated that the administration to normal individuals of an agent that augments catecholaminergic transmission induced in them a susceptibility to backward masking similar to that encountered in schizophrenics. As the authors rightly point out, while their findings are compatible with the notion of hyperdopaminergia-induced information processing dysfunction in schizophrenia, the hypothesis remains open to question. We wish to propose an alternative, not necessarily biochemical, explanation of the schizophrenic backward masking vulnerability, one that is linked to prefrontal impairment.The task utilized by Braff and Huey is fundamentally a test of proactive interference, a generic term for the negative effect exerted by a subsequently performed activity on a prior mental operation. In the case of the backward masking paradigm, this involves interference to the point of nonrecognition by a masking visual stimulus