The role of item distinctiveness in short-term recall of order information.

In two experiments, we examined short-term recall of order information using a partial-report distractor task. We manipulated the characteristics of a single letter in one of two four-letter segments. Participants knew in advance the identity of the letters in each segment. We made a single letter distinctive at presentation either by printing it in red or by replacing it with a red dash. Presenting the letter in red did not affect overall recall of the positions of the letters in the segment but did facilitate specific recall of the position of the distinct letter. Replacing the letter with a red dash inhibited overall recall as well as specific recall of the distinct letter. Participants were also less likely to respond in the regular output order when there was a dash replacing a letter in the segment. These effects of distinctiveness are explained in terms of output order processes in recent versions of the perturbation model.