Date of Degree
Coordination; Vocal learning; Zebra Finch
Social animals frequently emit communication calls. Although these calls are often innate in their acoustic structure, they can be used adaptably to coordinate behavior with other individuals. It is not known, however, what each animal needs to learn in order to achieve and maintain synchronized call patterns with others. To study this process, we have developed a vocal robot that can be programed to generate call patterns or to sense a bird's contact (short) calls and respond with precisely timed call answers. By varying the robot's vocal behavior, including call timing and rhythm, we tested how interacting zebra finches adapt to different call patterns produced by a partner robot bird. This approach allows us to assess engagement and the capacity to synchronize calls between females (vocal non-learners) and males (vocal learners) as well as birds with different levels of developmental social experience. We also tested if forebrain structures that are known to be involved in song learning are required for the coordination of calls. We discovered that zebra finches can learn to adjust the timing of their responses to a robot bird partner within minutes. Further, when challenged with complex rhythms containing jamming elements, birds dynamically adjusted the timing of their calls in anticipation of jamming. Blocking the song system cortical output dramatically reduced the precision of birds' response timing and abolished their ability to avoid jamming. Surprisingly, we observed this effect in both males and females, indicating that the female song system is functional rather than vestigial. We then tested if social interactions during development are necessary for birds to acquire the capacity to synchronize and adapt their call timing to those of a partner bird robot. We found that socially isolated birds were extremely imprecise in the timing of their responses. Further, they were unable to avoid disruptive jamming. Interestingly, these results were very similar to those observed after blocking the forebrain song system in socialized birds. We conclude that social interactions during development are necessary for zebra finch males to develop the capacity to precisely adapt the timing of their calls. Further, the capacity to synchronize calls must be acquired independently from that of song learning. Finally, we investigated if, and to what extent, birds can take into account the behavior of a third party while interacting with a partner. Using miniaturized wireless audio transmitters, we found that when two birds are interacting simultaneously with the vocal robot and with each other, they can avoid jamming with each other and with robot by cooperatively changing the latencies of their answer calls. These qualitative results suggest that birds are capable of adjusting the timing of their calls with respect to more than a single partner bird. Together, our results uncover behavioral and physiological mechanisms that give rise to vocal coordination, bridging a functional gap between innate and learned vocalization abilities.
Benichov, Jonathan I., "Mechanisms of Vocal Coordination in Zebra Finches" (2015). CUNY Academic Works.