The effect of selective attention and a stimulus prefix on the output order of immediate free recall of short and long lists.

Participants tend to initiate immediate free recall (IFR) of short lists of words with the first word in the list (Serial Position 1 [SP1]) and then proceed in forward serial order. Two potential explanations for this finding were examined: that the first items have increased selective attention (Experiment 1A and 1B) and enhanced temporal distinctiveness (Experiment 2) relative to subsequent list items. In Experiments 1A and 1B, participants were presented with lists of colored words for IFR. The experimental group was told that some trials would contain a red word and that when this occurred, they should output this word first in recall before recalling as many other words as they could. This instruction was designed to shift attention away from SP1 and toward the red item. The control group participants received identical stimuli but were unaware of the importance of the colored words and had no output order constraints. The overall recall of SP1 was not greatly affected in either experiment. In Experiment 2, participants were presented with lists containing between 2 and 12 words. Half of the trials contained a triple word stimulus prefix. For short lists in IFR, the overall recall of SP1 and the tendency to initiate recall with SP1 were reduced but far from eliminated by the stimulus prefix. We argue that our findings may be explained within a grouping interpretation in which the tendency to initiate recall with the first to-be-remembered item may reflect participants' tendency to output the first word in a highly salient participant-determined group.