Song learning of songbirds provides us a unique opportunity to study detailed mechanisms for vocal learning in various species, including humans. Recent studies in the behavioral neuroscience field have shown accumulated evidence indicating that their song learning is based on reinforcement via the auditory feedback of their own voice. The present review introduces an experimental paradigm that can elicit additional learning in bird's songs as a response to perturbations in the auditory feedback with noise presentation. This paradigm, named the noise-avoidance (NA) experiment, is quite useful for understanding the mechanism for song learning. Here I summarize findings obtained from the NA experiments, and review the current understanding of behavioral and neuroscientific mechanisms for feedback-based vocal learning. Additionally, I discuss computational aspects of the NA behavior in light of the reinforcement learning framework, and how the NA paradigm can be associated with the operant conditioning.
Altruistic behaviour, such as allogrooming and allofeeding, has been suggested to be crucial for maintenance of cooperative relationship especially between non-kin individuals. Monogamous pair-bond, which is widespread in birds, is a form of cooperation for breeding between a male and a female. Many previous studies reported that altruistic behaviour within pair-bonds occurred primarily from males to females. However, most of those findings were obtained from the observations during the breeding season, and therefore it remains unknown what sex-different patterns of altruistic behaviour occur outside the breeding season for life long monogamous birds. The present observation study investigated sex differences of altruistic behaviour within pair-bonds outside the breeding context in a life-long monogamy, large-billed crows (Corvus macrorhynchous). Specifically, frequency of allopreening and allofeeding were compared between sexes and also between pair-bonds. We found that frequency of both behaviour was different between sexes, and inconsistent within and between pair-bonds. Our findings suggest that altruistic behaviour within pair-bonds may occur asymmetrically between sexes but vary between pair-bonds in large-billed crows.
We introduce a unique art-science collaboration project organized by contemporary artists and comparative psychologists at Kyoto City Zoo in 2019. The objectives of this project were to evaluate how chimpanzees and humans respond to movies created by professional artists and to contribute to an outreach event at the zoo by demonstrating the entire research process to the public. We asked the artists to make short movies 'for chimpanzees' and presented those movies to chimpanzee and human participants while tracking the participants' eye movements using an eye-tracker. Both chimpanzees and humans looked at similar elements of movies, such as appearance of animal figures, targets of actions, and the center of abstract concentric figures. The differences between chimpanzees and humans were also pronounced; for example, human showed strong 'center bias' by keeping their gaze around the center of the screen, while chimpanzee did so to a lesser extent. This study not only offered comparative knowledge about responses to (artistic) movies in chimpanzees and humans but demonstrated how non-scientists can learn comparative psychology through an outreach project.