Long-term memory for 400 pictures on a common theme.

Long-term memory for large numbers of color photographs with a common motif--doors--was studied using pictures with two levels of informative cues: original photographs, and edited pictures in which extraneous information on details such as vegetation, paint scratches, signs, and lamp posts was removed. In the study phase, subjects viewed 400 pictures and were subsequently tested for memory on two-alternative forced-choice discriminations between studied and distracter pictures from the same picture category, at retention intervals between 0.5 h and 9 days. When tested with the nonedited original photographs immediate memory performance was close to 85% correct; when pictorial details were removed memory performance dropped by 20%. The decay functions were shallow with parallel paths for the categories of pictures. It is concluded that specific details of visual scenes contributed to long-term memory of those scenes.