Universal note preferences affect avian song learning
A study in the Behavioral Biology group of Carel ten Cate at the IBL showed that experience-dependent and -independent preferences influence song learning in zebra finches.
Songbirds and humans are often compared for their ability to learn vocalizations. Humans learn speech sounds and songbirds learn song notes, both by listening to adults. This learning by experience is necessary for normal speech sound or birdsong production in adulthood. Besides learning by experience it is hypothesized that both human infants and juvenile birds are also affected by conspecific sounds they have not been exposed to before. Former PhD-student Sita ter Haar (thesis defense: June 2013) tested if experience-independent note preferences influenced song learning in zebra finches.
Zebra finch likes
In the experiment, young birds were raised by their mothers only, who do not sing. Consequently, these birds had never heard conspecific song before. When they were tested for their note preference they indeed showed a preference for universal notes over uncommon ones. Birds were subsequently exposed to songs for a longer period in order to give them experience with song. One group of birds listened to artificially constructed songs with universal notes and another group listened to songs constructed from uncommon notes. After this learning period, birds preferred to listen to the songs they were exposed to, regardless of song notes being universal or not. Experience-dependent preference had overruled the experienced-independent one.
Impact on song development
How do these juvenile preferences influence the songs produced as adults? Birds of both groups learnt to a certain extent the song they were exposed to. Birds exposed to a universal song however, learnt the song slightly better than birds exposed to an uncommon song. Thus although the birds prefer songs heard before, their initial experience-independent preference affects the song learning. Such an interaction between experience-dependent and independent factors might also play a role in language learning in human infants.
Links
- The article was published in the Proceedings of the Royal Society B
- Personal page Carel ten Cate
- Link to PhD-thesis of Sita ter Haar