The control of feeding behavior by an imprinted stimulus.
Imprinted ducklings were trained to peck a pole using brief presentations of the imprinted stimulus as the response-contingent (reinforcing) event. Subjects were then permitted to spend extended periods with continuous access to food and the imprinted stimulus (via a pole peck). For other (control) subjects the experimental situation was restricted to either responding for the stimulus, or feeding in the absence of the stimulus. For subjects in the control conditions, both activities occurred in cyclic fashion. When, however, there was continuous opportunity to respond for the stimulus and food was available, the tendency to respond was related to the tendency to feed. Other experiments showed that independent presentations of the stimulus could initiate feeding in imprinted ducklings with no prior pairing of the stimulus with food and with no prior pole-peck training. The most consistent control over feeding, however, was exhibited by ducklings that were imprinted and also accustomed to periodic removals of the stimulus. It is concluded that in ducklings, imprinting procedures are sufficient to endow an arbitrary stimulus with the capacity to release feeding behavior.