Social facilitation of feeding behaviour in the domestic chick

Abstract 1. 1. The present investigation represents an attempt to obtain data relevant to the problems of development and stimulus control of social facilitation of feeding in the domestic chick. 2. 2. Chicks were reared in pairs or in isolation for four days following hatching. Under these conditions the paired birds ate significantly more than the isolates as indicated by greater weight gains. 3. 3. On the fifth day after hatching these same chicks were divided into four subgroups: isolation, visual social contact, partial social contact (paired but separated by wire screen), and complete social contact. With respect to amount eaten, the results indicated ( a ) that the method of rearing had no effect, ( b ) that there was no interaction between rearing and the immediate test condition, and ( c ) that complete social contact was necessary for the appearance of facilitation. 4. 4. Two additional experiments indicated that the results could not be accounted for by ( a ) differential weight loss in the isolated and social conditions, or ( b ) differential gain or loss due to compartment size or number of food cups available. 5. 5. Further observations of social interaction between chicks suggested that paired or grouped chicks may be led to eat more through pecking at one another's bills. It was demonstrated that a chick could be led to eat by simulating the movement of a companion's bill with a pencil. 6. 6. It was concluded that social facilitation of feeding does occur in young chicks, that unobstructed social interaction is necessary for its occurrence, and that it might be accounted for by bill pecking.