Song preferences predict the quality of vocal learning in zebra finches
In songbirds, learning to sing is a highly social process that likely involves social reward. Here, we hypothesized that the degree to which a juvenile songbird learns a song depends on the degree to which it finds that song rewarding to hear during vocal development. We tested this hypothesis by measuring song preferences in young birds during song learning and then analyzing their adult songs. Song preferences were measured in an operant key-pressing assay. Juvenile male zebra finches (Taeniopygia guttata) had access to two keys, each of which was associated with a higher likelihood of playing the song of their father or that of another familiar adult ("neighbor"). To minimize the effects of exposure on learning, we implemented a reinforcement schedule that allowed us to detect preferences while balancing exposure to each song. On average, the juveniles significantly preferred the fathers song early during song learning, before they were themselves singing. At around post-hatch day 60, their preference shifted to the neighbors song. At the end of the song learning period, we recorded the juveniles songs and compared them to the fathers and the neighbors song. All of the birds copied fathers song. The accuracy with which the fathers song was imitated was positively correlated with the peak strength of the preference for the fathers song during the sensitive period. Our results show that preference for a social stimulus, in this case a vocalization, predicted social learning during development.