Baldwin, J. M. (1903). Memory for square size. In J. M. Baldwin, Fragments in philosophy and science (pp. 248-256). London, Great Britain: John C. Nimmo.
http://dx.doi.org/10.1037/13706-013
This reprinted article originally appeared in Psychological Review, May 1895. The object of the experiments of this study was to determine the accuracy of the memory for size, as affected by the lapse of time. A figure of two dimensions was selected for experiment because of the tendency to measure linear size in terms of well-known units of length. The experiments proceeded by three different methods. (1) Selection from a Variety: A single figure (the normal, 150 mm square) was drawn on a blackboard and shown to a large college class; after a certain time a number of squares of various sizes were shown simultaneously, and the class was requested to designate the one that appeared to be the same size as the normal. The squares ranged from 130 to 210 mm, by intervals of 20 mm, and the time intervals were 10, 20, and 40 minutes. The class consisted of about 225 persons, of whom some 50 were women. (2) Identification: Here the normal square was first shown, and afterwards one other square; the subjects were asked to say whether the latter appeared to be greater, equal to, or less than the normal. The time intervals were the same as before, and the second square was in every instance 20 mm greater than the normal. Plotting the results, we find the memory curves, as they may be called, practically parallel, but the degree of accuracy is much higher by the second method than by the first. (3) The third series proceeded by what was termed the method of Reproduction: A normal square having been shown, as before, the subjects were asked, after the stated interval, to draw on paper a square of the same size. The normal in this case was 170 mm square. The reproductions were almost always too small, their average being 146.0 after 20 minutes and 146.4 after 40 minutes. The methods and results of further experiments in memory for square size are presented. (PsycINFO Database Record (c) 2016 APA, all rights reserved)