Measurement of visual memory span by means of the recall of dot-in-matrix patterns

A method for the study of visual memory span is described. The results of two dot-in-matrix experiments indicated that the patterns of larger matrix size were more difficult to recall, but the effect of visual angle was not significant. Visual memory span could be represented by the number of dota in the 5 by 6 or 6 by 6 pattern that a subject perfectly recalled with a probability of .5, since the proportion of recalled patterns was a monotonie decreasing function of the number of dots. This method can be used in group experiments without consideration of the differences in visual angles caused by the locations of subjects. The selection of appropriate presentation times and the distinction between verbal and visual memory spans are discussed.