Processes Underlying Clustering in Free Recall
Toshiaki Mori · Hiroshima University Acedemic Information Repository (Hiroshima University) · 1975
In free recall S is presented a list of words to learn, and he is told to recall the items in any order he wishes. Interestingly, certain regularities appear in the order in which the items are recalled. For example, there is a tendency for items which belong to the same category to be recalled together even though these items were not contiguous during presentation. This tendency for items belonging to the same category to be recalled together has been termed clustering. A long line of studies, beginning with the experiment by Bousfield (1953), have been concerned with this phenomenon of clustering, and have shown that clustering is a function of many variables, such as number of categories (Bousfield & Cohen, 1956; Dallett, 1964; Mandler, 1967), type of category (Cohen, 1963a; Cohen, 1963b), presentation order of words (Cofer, 1967; Cofer, Bruce, & Reicher, 1966), rate of presentation (Cofer, Bruce, & Reicher, 1966), frequency of words (Bousfield, Cohen, & Whitmarsh, 1958; Segal, 1969), and developmental level of subjects (Bousfield, Steward, & Cowan, 1964; Mandler & Stephens, 1967). However, the processes underlying clustering in free recall are so far only dimly understood. One of the most fundamental questions to be clarified is whether clustering occurs during storage or at the time of retrieval. Tulving (1968) has argued that items are stored in some coded fashion. The coding may take the form of unitization (chunking) of related items into the functional units. This coding is assumed to take place during storage. If categorized words comprised the list, S might recode them by forming chunks which could be tagged with the category label. At the time of retrieval, S merely has to recall the category label and reproduce the items from that category, consequently producing output organization. Slamecka (1968), on the other hand, put forth a different explanation of the clustering phenomena. He assumed that the specific item traces are being stored independently and the pattern of output organization reflects the nature of the retrieval process. This question of whether item traces are originally arranged into cohesive groups during storage, or this organization comes into being only at retrieval has been the subject of some debate but has not been yet satisfactorily resolved. One way of attempting to answer this question would be to inform S at time of retrieval that the words could be put into categories, while preventing him from detecting the structure of the list during presentation. In the present study, an incidental learning task was employed to prevent S from detecting the structure of the list. If clustering occurs during storage, such information given at the time of retrieval could not facilitate clustering. If, on the other hand, clustering occurs during the retrieval process, the information at the time of retrieval should facilitate clustering. Experiment I was, therefore, designed to investigate whether providing information on the list structure at the time of retrieval facilitates clustering in free recall.