The role of mental computations in judgments of area and volume

Abstract

Area and volume judgments are usually underestimates of true size. The possibility that these underestimations are more dependent on cognitive factors than on sensory ones was investigated in two experiments. In Experiment 1, subjects judged the products of multiplication problems varying in number of multiplications and number of digits per number. Judgments were analyzed using power functions. The power function exponents for problems requiring one multiplication and two multiplications were very similar to previously obtained exponents for judgments of area and volume, respectively. In Experiment 2, subjects judged three-number multiplication problems and volume ratios of depicted, rectangular boxes. Power-function exponents for these two kinds of tasks had similar means and standard deviations and were significantly correlated. These results support the hypothesis that underestimations of area and volume judgments are due primarily to errors in mental multiplication. © 1983 Psychonomic Society, Inc.