The Development of Habituation in the Domestic Chick

Abstract

Age-dependent changes in both within- and between-session habituation of locomotor activity were found in young Vantress x Arbor Acre chicks. In three experiments, 1- and 4-day-old chicks were given a series of either six short 10-min. habituation sessions or three long 20-min. habituation sessions in a large cylindrical drum. Individual locomotor activity was measured as the mean number of photocell beam interruptions/min. After their last activity session, the chicks were isolated for 3 hr. and then were tested for retention. Major findings were as follows: (a) the 4-day-old chicks showed significant within- and between-session decreases in activity during both the short and long habituation sessions; (b) the 1-day-old chicks did not show either within- or between-session habituation on the initial sessions when brief exposures were given, but did show significant habituation on the longer sessions; and (c) significant spontaneous recovery was observed in the chicks of both ages following the longer but not the shorter sessions. Rubel and Rosenthal (1975) have reported that 1- and 4-day-old chicks do not differ in their rate of habituation of an elicited eye-opening response. Therefore, our finding of an age-dependent change in the young chicks’ habituation of locomotor activity suggests that the precocial chick, like the altricial rat, shows an ontogenetic dissociation in habituation of elicited and emitted responses.