Parallel memory retrieval in dual-task situations: I. Semantic memory.
Gordon D. Logan, Matthew D. Schulkind · Journal of Experimental Psychology Human Perception & Performance · 2000
Can participants retrieve information about the 2nd of 2 stimuli while they are processing the 1st?Four experiments suggest they can.Reaction times to the 1st stimulus were faster if it came from the same category as the 2nd than if it came from a different category.This category-match effect was observed for letter-digit discrimination (Experiment 1), magnitude and parity judgments about digits (Experiment 2), and lexical decisions (Experiment 3).Experiment 4 showed that the 2nd stimulus could semantically prime the 1st.The category-match effect was observed only when the same task was performed on the 2 stimuli.When the task changed from the 1st stimulus to the 2nd, there was no advantage of a category match.This dependence on task set may explain previous failures to find parallel retrieval.This article is concerned with the possibility of parallel memory retrieval in dual-task situations.Can people retrieve information about one stimulus while they are busy processing another?This question has been important in the memory literature for decades, and many studies have addressed it throughout that period (see below).Many of the studies had procedural limitations that undermined their ability to address the question of parallel retrieval precisely.Two recent studies overcame these limitations by using the psychological refractory period (PRP) procedure, but they suggested opposite conclusions: Carrier and Pashler (1995) argued that memory retrieval was strictly serial, whereas Hommel's (1998) results suggest that memory retrieval may be parallel.Our research addressed procedural, analytic, and logical differences between the studies and found evidence supporting parallel retrieval that has implications for theories of the PRP as well as theories of memory.We should make clear that we are addressing parallel retrieval between tasks rather than within tasks.Most formal theories of memory assume parallel retrieval within tasks, in that a single memory probe accesses all traces in memory concurrently (e.g.,