Imprinting on time-structured acoustic stimuli in ducklings

Filial imprinting is a dedicated learning process that lacks explicit
reinforcement. The phenomenon itself is narrowly heritably canalized, but
its content, the representation of the parental object, reflects the
circumstances of the newborn. Imprinting has recently been shown to be
even more subtle and complex than previously envisaged, since ducklings
and chicks are now known to select and represent for later generalization
abstract conceptual properties of the objects they perceive as neonates,
including movement pattern, heterogeneity, and inter-component
relationships of same or different. Here we investigate day-old Mallard
(Anas platyrhynchos) ducklings’ bias towards imprinting on acoustic
stimuli made from mallards’ vocalizations as opposed to white noise,
whether they imprint on the temporal structure of brief acoustic stimuli
of either kind, and whether they generalize timing information across the
two sounds. Our data are consistent with a strong innate preference for
natural sounds, but do not reliably establish sensitivity to temporal
relations. This fits with the view that imprinting includes the
establishment of representations of both primary percepts and selective
abstract properties of their early perceptual input, meshing together
genetically transmitted prior predispositions with active selection and
processing of the perceptual input.