BLOCKING OF THE SEXUAL CONDITIONING OF DIFFERENTIALLY EFFECTIVE CONDITIONED-STIMULUS OBJECTS

The blocking phenomenon was investigated in the sexual response system of male Japanese quail. Access to a live female quail served as the u nconditioned stimulus (US). The same audiovisual cue served as the pre trained stimulus in all of the experiments. Following asymptotic condi tioning of the audiovisual cue, a second conditioned stimulus (CS2) wa s added. In Experiment 1, CS2 was a rectangular wood block that had li ttle or no resemblance to a female quail and could not support copulat ory behavior. In Experiment 2, CS2 was a terrycloth object that had no quail parts but could support copulatory behavior, and, in Experiment 3, CS2 was a terrycloth object that had a taxidermically prepared hea d of a female quail added. The terrycloth-only object supported more r apid conditioning than did the wood block, but the blocking effect was obtained with both kinds of stimuli. Approach responding to the terry cloth + head object required pairing it with copulatory opportunity, a nd the terrycloth + head object supported at least as rapid conditioni ng as did the terrycloth-only object. However, responding to the terry cloth + head object was not blocked by the pretrained audiovisual cue. These results indicate that the blocking effect occurs in sexual cond itioning even with stimulus objects that can support copulation. Howev er, the addition of species-typical head cues to an object makes that object such a powerful stimulus that conditioned approach responding t o it cannot be blocked by a previously conditioned arbitrary audiovisu al cue.