( baum chairman and professor of psychol...)'Uniquely human' component of language found in gregarious birds

Nusbaum, Margoliash and psychologist Kimberly Fenn had previously collaborated on studies of the role of sleep in speech perceptual learning. Gentner, a neuropsychologist, expert on starlings and, at the time, a postdoctoral fellow at the University of Chicago, was an essential addition.

To assess the birds' syntactical skills, the research team exploited the diverse sounds in starling songs. They recorded eight different 'rattles' and eight 'warbles' from a single male starling and combined them to construct a total of 16 artificial songs. These songs followed two different grammars, or patterning rules.

Eight songs followed the "finite-state" rule, the simplest sort, thought to account for all non-human communication. A finite-state grammar allows for sounds to be appended only at the beginning or end of a string. These songs were built up from a rattle-warble base by adding rattle-warble pairs at the end. The simplest song (ab) was one rattle followed by one warble. The next simplest a rattle, then a warble, followed by a different Rattle and Warble (abAB).

The other eight songs followed the "context-free" rule, which allows for sounds to be inserted in the middle of an acoustic string, the simplest form of recursive center-embedding. So a context-free sequence also began with rattle-warble base (ab) but built up by inserting new sounds in the middle, such as rattle-Rattle-Warble-warble (aABb).

Eleven adult birds were given lessons on distinguishing between these two sets of songs using classic reinforcement techniques. The birds were rewarded with food when they heard a song from the context-free set and for refraining when they heard one from the
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Source:University of Chicago Medical Center