Decerebrate Pigeon-Fear Signs

Abstract

Based on the statements of Flourens,1 McKendrick,2 Ferrier,3 Vulpian,4 Schrader5 and others,6 it is still believed that the pigeon deprived of its cerebral hemispheres, “exhibits no signs of fear.” In the study of such a pigeon,7 I observed repeatedly, indubitable signs of fear. Some of these signs were: dodging, starting, trembling, fleeing, struggling, staring, and crying out in a characteristic way. Since these signs, which show the semblance of fear, were produced in this decerebrate pigeon by stimuli that ordinarily produce fear in nomal pigeons, they may, perhaps, be called signs of fear.As examples of fear reactions we cite only a few, as follows:Sound Fear Reactions—One hour after the operation, clapping of the hands caused the head to move, the body to tremble, and the wings to shuffle. Fifteen hours after the operation, clapping the hands caused the head to rise and the eyes to stare. On the 42nd day after the operation, snapping a ruler on a table 8 to 10 times in succession, caused the head an...