Complexity effects in visuo-spatial working memory: Implications for the role of long-term memory

Several studies have shown that the capacity of visuo-spatial working memor y is limited by complexity. Using a variant of the Corsi blocks task, this paper investigates the effect of complexity of the to-be-remembered path on visuo-spatial memory span. Redundancy was determined by three Gestalt prin ciples: symmetry, repetition, and continuation. Experiment 1 revealed an ef fect of path complexity. The subsequent experiments explored whether the su periority for recall of structured over complex paths can be attributed sol ely to the operation of visuo-spatial working memory, or whether it also re flects the use of long-term knowledge. Experiment 2 demonstrated that the e ffect of complexity remained, even when the mechanisms for visuo-spatial co ding were removed by a secondary visuo-spatial task. In Experiments 3 and 4 subjects were trained in the recall of complex paths. This led to the crea tion of long-term memory representations for these paths, as shown by an im provement in their span, and a concomitant lack of transfer to new paths. F inally, Experiment 5 showed that one prior repetition of a complex path was sufficient to produce specific and long-term learning effects. These resul ts point to the involvement of long-term memory processes in the temporary retention of visuo-spatial material for which representations exist in long -term memory. They also suggest that the effect of complexity may provide a tractable technique for investigating the mechanisms underlying the limits of visuo-spatial short-term storage.