Female Budgerigars Attend Equally to Rhythmic Beat or Repetition, While Humans Prioritize Their Combination.

Rhythm is an essential aspect of human music, typically characterized by temporal regularity of sound events and repetition of rhythmic patterns. One key biological trait for human rhythmic behavior is the ability to entrain movement to sound events, an ability possibly related to vocal production learning. Parrots share both of these crucial traits with humans. Budgerigars in particular can entrain to a beat, and female budgerigars, like humans, prefer rhythmic sounds. What remains unclear is whether this attraction to rhythm is based on the same features that are important in humans. If so, this could suggest shared mechanisms and/or functions. Using a three-choice place preference paradigm for both species, we found that female, but not male, budgerigars preferred rhythmic over arrhythmic stimuli, with equal preference for repetition and regularity. Humans preferred stimuli containing a regular beat, with a tendency to prioritize the combination of regularity and repetition. We suggest that female budgerigar preferences are driven by features of budgerigar warble song displayed in courtship contexts, while humans are driven by group chorusing behavior. We discuss how differential behavioral exploitation of shared biological traits may have had different evolutionary consequences and offer suggestions for how these can be tested.