Adaptation to optically produced curvature of frontal planes

A new kind of adaptation was discovered, namely, to glasses that cause frontal planes to appear concave. The effect of this adaptation can be observed without the glasses as an apparent convexity of a frontal plane. We measured this effect by bending a frontal plane into a concave surface that compensated for this convexity. To obtain rapid adaptation, the subject must nod his head during the exposure period so that the concavity is seen to shift through a frontal pattern. Causing the same shift by moving the pattern up and down instead of the subject’s moving his head does not produce such an adaptation. Head movements are, however, not necessary for the adaptation effect to become manifest.