Serial position effects in the recall of picture sequences

Sequences of 10 pictures of familiar objects were presented for immediate recall, and typically bow-shaped serial position curves were obtained. The effects of redundant stimulus suffixes, and of redundant stimulus prefixes, which could be either extra pictures, or written words (the names of similar familiar objects) were examined. In the prefix conditions, extra words produced a general decrement over positions 1-4, as compared with a control condition. Picture prefixes had no effect. In the suffix conditions, redundant words affected positions 9 and 10, whereas the main effect of redundant pictures was at positions 8 and 9. The differential serial position effects are taken to reflect the presence of two memory codes, a verbal one and a visual one, which vary in trace-strength or accessibility at different list positions.