The role of retrieval in schizophrenic memory deficit.

Abstract

In order to distinguish between information that is unavailable or inaccessible in the schizophrenic's memory store, 48 schizophrenics and 48 normals learned three lists of categorized words. The lists were either cued or not cued at recall. Demographic and pretest measures validated the diagnosis of schizophrenia and indicated no significant differences between the experimental groups on age, education, intelligence, and categorizing ability. The results indicated that under conditions where the input did not exceed the limits of immediate memory span, schizophrenic memory deficit could be explained in terms of an "inaccessibility" of items due to a retrieval dysfunction. Under conditions where input exceeded these limits, the recall analysis was suggestive of an "unavailability" of items in the memory store. It was concluded that schizophrenics suffer deficits throughout the information processing system rather than at any specific stage. The locus of breakdown was dependent on the task demands of the experimental situation.Conceptualizations of schizophrenic memory deficit have significantly broadened in recent years. Traditional approaches (e.g. Cameron, 1938;Shakow, 1963;Yates, 1966;McGhie, 1969) have emphasized the disruption of input either as the information enters the processing system or at early stages of the system. Research based on this approach has typically focused on the processes involved in perceiving and/or attending to the incoming stimuli.However, recent investigations have attempted to demonstrate the involvement of other factors in schizophrenic memory deficit. Bauman and Murray (1968) and Bauman (1971a, b) investigated (1) recognition and recall performance and (2) the serial position of omissions of schizophrenic memory. Their results demonstrated an inferiority in performance for schizophrenics only under the recall task. In the recognition memory task there were no significant differences between the normals and schizophrenics. They interpreted this result as indicating an inability of the schizophrenics to adequately organize the memory store. They also found This article is based upon part of a dissertation submitted to the University of Manitoba in partial fulfillment of the requirements for the PHD degree. The author would like to thank his supervisor, M. Wright, and his committee, particularly J.S.

Individual Differences in Episodic Memory: The Role of Self-initiated Encoding Strategies

“…Language studies of semantic processing in individuals with schizophrenia have suggested that they have impairments in the ability to access and/or retrieve semantic knowledge (for a review, see Kuperberg and others 2006), which could mean that individuals with schizophrenia cannot effectively use semantic encoding strategies due to semantic processing deficits. However, studies in which individuals with schizophrenia are instructed to sort words in unblocked categorized lists into different categories have shown that they are able to group words by their meaning (Russell and Beekhuis 1976;Barker 1977;Calev and others 1983;McClain 1983). There is also evidence to suggest that semantic encoding strategies are effective learning strategies for individuals with schizophrenia.…”

“…Providing the names of the categories of words in a list before encoding can also enhance individuals with schizophrenia's memory performance (Chan and others 2000), although not to the level of memory performance of healthy controls. However, providing strategic support during both encoding and retrieval, for example, by giving the names of the categories of words in a list before encoding or providing the category labels for each word during encoding and additionally providing the names of word categories as retrieval cues during recall, can result in equivalent memory performance for individuals with schizophrenia and healthy controls (Barker 1977, McClain 1983. This suggests that individuals with schizophrenia have deficits in self-initiated semantic strategy use during both encoding and retrieval.…”

The Effect of a Dual Level Word List on Schizophrenic Free Recall

“…Only three of the previously mentioned experiments (Koh, Kayton, and Berry 1973;Traupmann 1975;Barker 1977) used a categorical clustering format. Koh, Kayton, and Berry (1973) and Barker (1977) presented recall data for the first trial, but initial trial clustering data were not mentioned by any of these investigators.…”

“…Only three of the previously mentioned experiments (Koh, Kayton, and Berry 1973;Traupmann 1975;Barker 1977) used a categorical clustering format. Koh, Kayton, and Berry (1973) and Barker (1977) presented recall data for the first trial, but initial trial clustering data were not mentioned by any of these investigators. Because all three experiments essentially involved a subjective organization procedure, it is unclear whether the schizophrenic possesses an organization that is idiosyncratic or whether he possesses an organization that corresponds to the "frame of refer-ence" which the majority of people recognize.…”

“…Again, neither clustering nor recall data were reported for the first trial. Barker (1977) used cued and free recall of lists containing 24 words with varying numbers of categories and category size. He found normals recalled significantly more words than schizophrenics under all situations except cued recall of the list with the fewest categories (six categories of four words apiece).…”