Ekman, G., and Junge, K. Psychophysical relations in visual perception of length, area and volume.Scand. J. Psychol., 1961,2, 1–10. — Subjective length, area and volume as functions of the corresponding stimulus variables were studied in three experiments. The exponents of the psychophysical power functions scattered around 1 for perception of ‘real’ space. For perspective drawings of cubes and spheres, however, the exponents were about 0.75. From a further analysis of the data it was tentatively concluded that perspective and shadow are insufficient cues to visual volume, and that the subjective scale reflects perception of area rather than volume, especially in the case of small