The Moon Illusion as a Function of Binocular Regard

Schuri has shown that the moon illusion depends upon the elevation of the regard and occurs in full amount only at considerable distances (at 100 ft. and further). Holway and Boring2 have shown that the illusion depends upon the orientation of the eyes in the head: the apparent size of a distant object like the moon, for the erect, supine or intermediately inclined O, is greatest when the eyes are in the 'primary' position, and least when the eyes are maximally raised or lowered. The eyes can move with