Classical conditioning of goldfish in the shuttlebox

Goldfish trained in a shuttlebox with light as CS and brief shock as US acquire the shuttling response to light whether or not an avoidance contingency is in effect. That the change in behavior produced by the classical procedure is not due merely to sensitization is demonstrated by a discriminative control. The results suggest the usefulness of the shuttlebox for the study of classical conditioning in goldfish and call into question the instrumental interpretation of the change in behavior produced by the avoidance procedure.