Short-term conceptual memory for pictures.

Three converving procedures were used to determine whether pictures presented in a rapid sequence at rates comparable to eye fixations are understood and then quickly forgotten. In two experiments, sequences of 16 color photographs were presented at rates of 113, 167, or 333 msec per picture. In one group, subjects were given an immediate test of recognition memory for the pictures and in other groups they searched for a target picture. Even when the target had only been specified by a title (e.g., a boat) detection of a target was strikingly superior to recognition memory. Detection was slightly but significantly better for pictured than named targets. In a third experiment pictures were presented for 50, 70, 90 or 120 msec preceded and followed by a visual mask; at 120 msec recognition memory was as accurate as detection had been. The results, taken together with those in 1969 of Potter and Levy for slower rates of sequential presentation, suggest that on the average a scene is understood and so becomes immune to ordinary visual masking within about 100 msec but requires about 300 msec of further processing before the memory representation is resistant to conceptual masking from a following picture. Possible functions of a short-term conceptual memory, such as the control of eye fixations, are discussed.