What songbirds can teach us about human speech

When a young songbird learns the song of a nearby adult bird, neurons in deep layers of the young bird’s auditory cortex become attuned to the acoustic properties of that song, suggests a paper in Nature Neuroscience this week. This research highlights how vocal communication shapes auditory coding in songbirds and suggests that a similar process could support speech learning in humans during early childhood.

Both humans and songbirds develop life-long hearing and communication skills from auditory cues experienced in infancy. As a result, the human auditory cortex responds preferentially to speech compared to other sounds. Similarly, the songbird auditory cortex responds preferentially to song over synthetic sounds. However, it is unknown whether this tuning is fixed from an early age, or whether it develops in a species-specific manner.

Sarah Woolley and Jordan Moore studied the song development and the tuning of neurons in the auditory cortex of two species of songbirds: zebra finch (Taeniopygia guttata) and long-tailed finch (Poephila acuticauda). Some birds learned songs from their own species, whereas others were tutored by foster parents of a third species, the Bengalese finch (Lonchura striata domestica). The authors found that juvenile birds learned to mimic the songs of their tutor, and their auditory cortical neurons became tuned to the specific sounds of the leaned song, independent of the species of the tutor bird.

The authors conclude that these findings reveal how early songbird vocal communication shapes auditory coding. They also suggest that similar processes could explain why early exposure to language-specific sounds can predict adult human speech perception.