An imprinting object rapidly acquires high attractiveness when associated with food delivery

Young precocial birds develop a preference for an imprinting object by mere visual exposure to it in the absence of conventional physiological reinforcement. The lack of the necessity of conventional reinforcement for imprinting, however, does not mean that such reinforcement is unimportant. The evidence presented here shows that an imprinting object rapidly acquires high attractiveness to young chicks when it is associated with food provisioning. Domestic chicks, Gallus gallus domesticus, were first exposed to two different imprinting objects in the absence of any reinforcement. Subsequently, two groups of chicks received a single feeding session wherein they were provided with prey from one of the imprinting objects. A third group served as a control in which the chicks were exposed to one of the imprinting objects and prey delivery in an unpaired way. Finally, all chicks received two choice tests to assess their preferences for the two imprinting objects. The chicks that received food from an imprinting object strongly preferred that object to the alternative familiar-only object, and preferred the familiar-only object to a novel object. The control group did not show any preference between the two imprinting objects, but preferred the unpaired imprinting object to a novel object. These results suggest that primary-need reinforcers such as food contribute to increasing the attractiveness of an imprinting object by promoting rapid associative learning.