Abstract: College students were tested with a dual task tecnique to examine the effects of divided attention (DA) at encoding or retrieval on perceptual grouping processes in short-term memory. The results showed that memory performance of perceptually grouoed lists were significantly better than that of ungrouped lists under full attention in both free recall and serial recall, indicating a perceptual grouping effect. DA at encoding disrupted mis effect in both free recall and serial recall, by contrast, DA at retrieval disrupted it in serial recall alone, leaving it unaffected in free recall, revealing different characteristics in free recall and serial recall. The authors assumed that perceptual grouping processes in short-term memory occurred at both encoding and retrieval phases, and the encoding phase is the primary one which demands relatively more attentional resources.

Key words: short-term memory, perceptual grouping, full attention, divided attention