The challenges of learning complex behavioral sequences – lessons from songbirds
How does one learn a complex motor skill with many constituent parts, such as a song, a dance, a language, or a sports game? In both humans and animals, learning complex behaviors seems to rely on a gradual approximation of an internal representation of the desired behavior, rather than on external rewards or punishments. However, finding a way to adjust one’s own behavior to match a complex internal goal is a computationally daunting task; it may be more efficient not to treat the entire behavior as a single goal, but instead to divide it into sub-goals and use distinct subroutines to attain each. We find that young Zebra finches (Taeniopygia guttata) employ such “divide and conquer” approach to imitate the elaborate songs of adult individuals. To infer song learning strategies, we use artificial “tutors” that induce young birds to imitate a synthetic song, and then to adjust their performance to match a newly presented song. This allows us to manipulate the acoustic mismatch between a bird’s current song and his learning target. We find that zebra finches decompose the complex task of song learning into two independent subtasks: first matching the syllable repertoire of their tutor regardless of correct sequential order, and later matching the order of target syllables. Moreover, birds employ learning strategies that are specific to distinct levels within their song hierarchy: while the syllable repertoire of the song is learned independently of syllable ordering, the structure of sub-syllabic notes is learned with respect to neighboring notes within a syllable. This combination of strategies may be an adaptation to efficient learning of a complex motor skill within a relatively short developmental time window.
Dr. Dina Lipkind is currently in the Department of Biology, City University of New York, York College.
The event is free and open to the public.