Studies of rhythmic synchronization in avian vocal learners using operant conditioning methods

Researchers have argued that non-human animals exhibit a sense of rhythm. Budgerigars and Bengalese finches were trained to peck a key iteratively in response to metronomic stimuli using an operant conditioning method. Peck timing in Budgerigars was distributed around the stimulus onset of the metronome, suggesting the birds synchronized their body movement to the rhythm of the metronome. However, peck timing in finches appeared to correspond to an estimated reaction time, suggesting that peck responses were a mere reaction to the metronome stimuli. Next, budgerigars were trained to peck two keys alternatively without any metronomic stimuli, so that pecking of the keys was self-paced. Metronomic sounds were created to match the intervals of the self-paced pecking. Additional metronomic stimuli were created to be 10% faster, 10% slower, and 20% slower than the original self-paced metronome stimuli for each bird. These sped up or slowed down metronomic sounds were played back in the background of the self-paced pecking task. In this experiment, rhythmic synchronization was not observed; however, one bird exhibited shorter pecking intervals for the faster metronome and longer intervals for the slower metronome, suggesting that the metronomic stimuli influenced peck timing in this bird in the absence of training.