Fragment and schema models for recall

Two general conceptualizations of recall may be distinguished. One holds that recall is sub-served by memory traces in which representations of different aspects of external events are linked directly to each other. The other holds that these representations are connected via a mediating concept. Formalizations of these views are provided by two theories examined by Ross and Bower (1981a): the “fragment” and “schema” models, respectively. Ross and Bower found that patterns of cued recall of clusters of words with a common theme were predicted well by the schema model, but not by the fragment model. Two experiments reported here show that the reverse is true if the clusters of words are selected randomly. Ross and Bower also considered separately a third theory, the “horizontal” model. However, the horizontal model is shown here to be a constrained form of the fragment model. Another constrained form of the fragment model, termed the “link” model, is introduced and is shown to provide an account of encoding as well as of retrieval that, although it is outstandingly parsimonious, is also approximately accurate. Finally, it is shown that the memory structures characterized by the fragment model may be interpreted as either graphs or digraphs: that is, networks with either bidirectional or unidirectional connections between nodes.