The effects of spatial, temporal, and control variables on the free-recall serial position curve of retardates and equal-MA normals.

In Experiment I seven pictures were sequentially illuminated at a 3-see rate through seven translucent windows. A different window provided the starting point for each of seven tests. Retarded and normal Ss of equal MA produced equivalent free recall and reliable recency effects. Although groups did not differ significantly at any portion of the curve, only the normals produced a significant primacy effect. The spatial end anchors produced no significant primacy or recency effects. In Experiment II total presentation time remained the same but the pictures were presented at a 1-sec rate. Variations in elapsed time and number of Presentations produced a negative primacy effect, a result attributed to the prevention of selective rehearsal and the resultant interaction of trace decay and order of recall. Superior recall by the normals, particularly in the recency portion of the curve, was attributed to group differences in order of recall strategies.