Properties of human visual memory for block patterns.

Several characteristics of human short-term visual memory (STVM) were specified through a series of experiments, by using block patterns (BPs) of varying complexity and matrix size (n-by-n). For each matrix size, BPs with high and low complexity were formed (i.e. n-by-n-H and n-by-n-L). In experiment I, the characteristics of the acquisition process were examined through a recall task. The recall rate for a single glance (exposure time less than 0.3 s) is more than 90% for 3-by-3 and 4-by-4-L BPs. For 4-by-4-H BPs, an improvement in recall rate was not found even when exposure time was increased to 2.4s. The recall rate for 6-by-6-H, 7-by-7, and 8-by-8 BPs did not change even when the exposure time was increased to 9s. In experiment II, the characteristics of the STVM decay process were examined using a recall task. Though a difference between the 4-by-4-L and 4-by-4-H acquisition rates was found, no difference was found in the forgetting rates. No decay was found for 6-by-6 BPs. Furthermore, the information obtained during a short duration was not forgotten for 4-by-4, and 6-by-6 BPs. It was concluded from these results that: 1) The acquisition rate into STVM depends upon figural complexity. 2) The decay rate does not depend upon figural complexity. 3) The limit of STVM was between 4-by-4-L, and 4-by-4-H BPs.(ABSTRACT TRUNCATED AT 250 WORDS)