Selective pair recognition memory impairment with no response bias in schizophrenia.

Memory is one of the cognitive functions most affected in schizophrenia, but the severity of deficits varies from one task to another. In particular, greater impairments have been reported for pair recognition than item recognition. However, decision biases and how they could affect memory dysfunction in schizophrenia have received scant attention. In this study, 26 people with schizophrenia and 28 healthy controls were administrated an association item recognition task. During encoding, participants studied pairs of visual objects, and they had to memorise objects and their pairing. In a subsequent retrieval task, participants performed an item recognition test (old/new items) and a pair recognition test (intact/rearranged pairs). Results showed that both groups were better at recognizing items than pairs, with lower performance for pair recognition, but not for item recognition, in people with schizophrenia. Analyses of response biases revealed that patients had a conservative response bias for items but not for pairs. The study also provides evidence that associative impairment may not result from decisional bias but rather from impairments in mnesic processes.