The essential elements of an ecological approach to Pavlovian conditioning

Pavlov was primarily an experimentalist rather than a naturalist. Although he was mindful of what his dogs might encounter in their natural environment, he was primarily interested in experimental control and precision rather than ecological validity. I discuss three essential elements of an ecological approach. First, in an ecological study the conditioned stimulus or CS is not "neutral" or "arbitrary" but has an inherent or pre-existing relation to the unconditioned stimulus or US. Conditioning with such ecological CSs produces results that are often different from what occurs with arbitrary CSs. Second, an ecological approach is focused on how a CS alters responding to the unconditioned stimulus or US. Numerous examples of conditioned modification of responding to the unconditioned response or UR are described, along with mechanisms that involve CR/UR summation and Pavlovian sensitization of reactivity to the US. The adaptive significance of the latter has been directly demonstrated in studies of conditioned fertility. Third, an ecological approach considers Pavlovian conditioning as the fine tuning of complex behavior systems that evolved to accomplish major tasks of living such as avoiding predators, finding food, and successfully reproducing. In considering how Pavlovian conditioning may alter a behavior system, an ecological approach emphasizes both changes in efferents or behaviors as well as changes in afferents or sensitivity to stimuli that are relevant to the behavior system.