A study of the extinction of unconditioned reflexes.

Abstract

Extinction and disinhibition were demonstrated in the tail reflex of the spinal rat, the startle response of the normal rat, and the abdominal reflex of man. Where successive extinctions with interpolated disinhibitions were used the curves of successive extinctions are negatively accelerated and are essentially the same for all 3 responses. The extent of successive recoveries to disinhibition is a logarithmic function. No extinction was found in the patellar reflex of the normal or the spinal cat, in the human biceps reflex, or in the human pupillary response to faint light or to sound.