Naturalistic Conditioned Stimuli Facilitate Sexual Conditioning Because of their Similarity with the Unconditioned Stimulus

Previous sexual conditioning studies with male Japanese quail have shown that adding taxidermic female head and neck cues to a conditioned stimulus (CS) facilitates conditioned sexual responding. The present experiment examined CS-US similarity as a possible mechanism for this facilitation. During sexual conditioning trials, artificially colored CSs with or without taxidermic female head cues were paired with copulatory access to artificially colored female quail (the unconditioned stimulus or US) to form similar and dissimilar CS-US combinations. As in previous experiments the presence of taxidermic female cues on the CS enhanced conditioned copulatory responding. Additionally, more conditioned copulatory responding developed when the CS and US colors were similar compared to when they were different. The results indicate that similarity between the CS and US strengthens the sexual conditioning of male quail, and similarity in color is more important than similarity in shape. The results also suggest that CS-US similarity may be one factor responsible for the facilitated conditioned responding that occurs when female cues are added to a CS object. The behavior systems approach is used to interpret the findings