Inhibitory processes in memory are impaired in schizophrenia: evidence from retrieval induced forgetting

Schizophrenic patients are known to exhibit inhibitory impairments in response suppression and selective attention. However, the impairment of inhibitory control in memory retrieval has not clearly been documented. In two experiments, we investigate inhibition in memory retrieval by using the retrieval practice procedure. In Expt 1, a cued recall final test was used. Consistent with previous research, we found similar retrieval-induced forgetting (RIF) effects in schizophrenic patients and in controls. However, these effects could be the result of interference/blocking or the results of inhibition. In order to reduce the influence of blocking in Expt 2, we used a recognition test. We found that RIF was reduced in patients, compared to healthy controls. The elimination of RIF effect in patients, when the influence of blocking is reduced, indicates that inhibitory processes in memory are altered in schizophrenia. Result suggest that schizophrenic patients suffer from critical impairments in inhibitory processes involved in memory retrieval, similar to the inhibitory deficits found in other cognitive domains.