Visual discrimination learning of the young chick: Key‐peck conditioning with heat‐light reinforcement

Heat‐light reinforcement procedures are described which were developed for key‐peck conditioning of 1‐day‐old chicks. 24 Vantress x Arbor Acre and 24 White Leghorn chicks were randomly assigned to two preference conditions in a successive discrimination problem: bright yellow as S + and dim blue as S − , or the reverse. During 7 sessions of 48 discrete conditioning trials each, the chicks learned quickly to peck the key when the S + was presented and to inhibit pecks when the S − was presented. This differential responding to S + and S − was evident when the chicks were 1 day old (sessions 1 and 2) and became more evident with further training when the chicks were 2 days old (sessions 3–7). There were no significant preference or breed differences. Contrary to previous results, this experiment demonstrated that neural mechanisms involved in inhibition of responses are well developed in the young chick.