Memory psychophysics for visual area and length.

Independent groups of observers made magnitude estimates of geographical area or interstate distance. In Experiment 1, observers estimated the areas of nations or of states of the United States from memory. In Experiment 2, estimates of state area were made either with a map present or from memory after the map had been studied. Similarly, in Experiment 3, observers made perceptual or memorial estimates of interstate distances. Perceptual estimates of distance and geographical area were related to actual stimulus magnitude by power functions whose exponents were similar to those found with conventional procedures. Memory estimates were also related to actual area and distance by power functions. Comparison of memory and perceptual exponents showed that for both area and distance, the memory exponent was equal to the square of the perceptual exponent. The results of Experiment 3 were predicted by a "re-perceptual" model of memory for continuous dimensions, which was developed to describe the results of Experiment 2.