Pavlovian conditioning of sexual behavior in male threespine stickleback (Gasterosteus aculeatus)

This study examines whether the sexual behavior of male threespine stickleback (Gasterosteus aculeatus) can be conditioned using a Pavlovian conditioning procedure. Eight males were trained to discriminate between a red and a green signal where one signal (reinforced conditioned stimulus, CS+) was followed by the presentation of a gravid female and the other signal (nonreinforced stimulus, CS-) was never followed by the presentation of a female. After the training phase (240 trials), males were presented with extinction trials (160 trials). Males rapidly learned the discrimination task, performing more approaches and zigzags (a courtship dance) to the CS+ than to the CS- during training trials. Throughout the extinction phase, males continued to approach and zigzag more to the CS+ than to the CS-, but conditioned responses to the CS+ slowly declined over this phase. Learning may be an adaptive mechanism by which a male anticipates a potential mate, and becomes prepared to court, rather than attack, an approaching female.