Development of filial attachment to static visual features of an imprinting object

Three experiments investigated the fact that the static visual features of an imprinting object (its color, size, and shape characteristics, as represented by the object remaining stationary during its presentation) can gradually acquire control over filial behavior by virtue of their repeated spatial-temporal pairing with visual motion—an effect that has been interpreted as a process of classical conditioning. Experiment 1 found that the static features can acquire control if they are made conspicuous in some other, nonmovement way (i.e., by manipulating the relative illumination of the imprinting object). Further experiments then failed to find any qualitative difference between the behavioral control developed by conspicuous but static aspects of a duckling’s environment and the control developed by the static features of a moving object, either in terms of persistence of the acquired control (Experiment 2) or in terms of possible restrictions imposed by the sensitive period for imprinting (Experiment 3). Taken together, these results support the plausibility of a perceptual learning hypothesis, although the classical conditioning view was not itself contradicted. The present findings are also relevant to the broader issue of whether any valid distinctions exist between the behavioral control exerted by static aspects of a precocial bird’s environment and the control exerted by animate, presumably social stimuli.