Psychophysical functions for perceived and remembered distance.

Two separate groups of subjects made magnitude estimations of the distances to fifteen objects (from 20 ft to 14.28 miles away) situated in a landscape. On day 1 of the experiment both groups learned the names and locations of the objects while viewing them from the top of a small mountain. On day 2 the perception group (N = 19) judged the distances to the objects while viewing them from the top of the mountain, whereas the memory group (N = 18) judged the distances while visualizing the landscape from memory. The data for both groups were well fit by power functions; the exponent was reliably smaller for the memory group (0.596) than for the perception group (0.811). Both groups drew maps of the landscape (reproduction task) from memory and the exponents were 0.483 and 0.514 for the memory and perception groups, respectively. The results are discussed in light of possible transformations performed on the original stimulus inputs by the sensory/perceptual and the memorial systems.