Abstract
A common finding in visual short-term memory tasks is a linear increase in reaction time with the increase in memory load. The RT function is assumed to reflect memory search processes during the retrieval phase of the short-term memory task. Using the PRP dual task paradigm, the present study examined whether central attention is involved in memory search during retrieval. Following previous suggestions that qualitatively different processes occur in VSTM tasks with short and longer delay periods, the involvement of central attention in retrieval was examined separately for short and long delays. Two groups of participants performed a color short-term memory task, one group with a short delay period of 1.5 seconds, and the second group with a longer delay period of 6 seconds. The load was varied between one and three items. During the retrieval phase of the memory task, participants performed a secondary tone discrimination task that occupied central attention while they were searching through the memory set. The results showed a dissociation between short and long delays. The occurrence of the concurrent tone discrimination task had no impact on retrieval processes in the short delay condition, but led to the postponement of retrieval processes in the long delay condition. Taken together, the experiments provide evidence that central attention is involved in retrieval processes, only when items are maintained for longer periods, and emphasize further the qualitative distinction between VSTM tasks with short and long delays.
Meeting abstract presented at VSS 2012