More things in heaven and earth: A reply to Loftus.

Abstract

Observers perceive not the constancy of the moon's subtense, but its failure to reach projected subtenses. These subtense projections are based on visual experience provided by the geometry of terrestrial passage. In such passage, visual subtenses of objects increase with elevation, and they increase less for high objects and details than for lower objects and details. There is between elevation and subtense a perceptual invariance that holds for terrestrial objects though not for celestial objects. The moon's unchanging subtense is consistent with a variety of assumptions of altitude; magnitude of the illusion depends on the observer's recognition that subtenses of objects at great altitude change little with elevation. The illusion is most coherently-though perhaps not most simply-described by saying that the moon seems a remarkably large object at horizon and that it distances as it rises.

Moon illusions redescribed

“…New attempts to explain this "larger and closer" illusion continue to appear, with each writer noting how previous explanations (theories) fail (Baird, 1982;Baird & Wagner, 1982;Enright, 1975;Gilinsky, 1980;Hershenson, 1982;Loftus, 1985;Reed, 1984Reed, , 1985Restle, 1970;Smith, Smith, Geist, & Zimmermann, 1978). The present article l extends the argument (McCready, 1965(McCready, , 1983(McCready, , 1985 that published explanations fall short of the mark primarily because, in addition to the perceived distance variable, V' m, they use only one "perceived size" variable instead of both the perceived linear size value, S' m, and the perceived visual angle value, V' deg (the perceived optical direction difference).…”

“…The difference between our frequent exposure to things passing overhead in flat trajectories, and our infrequent exposure to things passing over in arched trajectories, is important, however, to Reed's (1984Reed's ( , 1985 "terrestrial passage" theory of the moon illusion.…”