Mirror-image stimulation and tonic immobility in chickens

Abstract

Group-reared chicks manually restrained in the presence of an unrestrained conspecific remained immobile for less time than birds restrained in isolation. On the other hand, chicks restrained in front of their own reflection in a mirror showed exaggerated tonic immobility reactions. Using differently prepared dead conspecifics as stimuli, it was determined that the reason a mirror prolongs the immobility episode relates to the reflected gaze of the “other” immobilized bird. © 1972, The Psychonomic Society, Inc.. All rights reserved.