There’s a specific way of speaking that we instinctively reserve for conversations with (or at) the youngest humans: Our voices get slower and more high-pitched, our sentences repeat themselves (“Are you sleepy? Yes you are, yes you are”). If I did it to you, it’d be weird. If I did it while talking to an infant, though, it’d be totally normal — a little grating, perhaps, but socially acceptable nonetheless.
But baby talk isn’t just some strange social ritual — past studies have found it to have real benefits for the babies on the receiving end. Baby brains spend months rehearsing speech before they utter their first words, and during that time, they’re soaking up every squeaky, cutesy thing adults say. In general, chattering to babies can help their cognitive development, and some research suggests that baby talk in particular encourages infants to babble more than when adults simply speak to them in a normal tone of voice. (The babbling, in turn, helps with language development, especially when you pretend to understand what they’re saying.)
And new research suggests not only that birds may have their own form of baby talk, but that it helps baby birds in much the same way. In a study published yesterday in the Proceedings of the National Academy of Sciences, a team of researchers from McGill University tracked two groups of baby zebra finches over five days as they learned how to sing. Half of the baby birds were allowed to interact with an adult zebra finch (the researchers called this group the “socially tutored” group), while the other half listened to recordings of an adult bird’s vocalizations (“passively tutored”).
Once this learning period was over, the researchers tracked the baby birds’ vocal development for an additional ten weeks or so, comparing their songs to the sounds made by their “tutors” to see how well they’d internalized the lessons. When they ran the acoustical analyses, they found that the babies that had had social interaction with adults were better able to mirror their sounds. What’s more, the two groups actually learned slightly different songs: When adult finches were interacting directly with the babies, their sounds were slower and more repetitive, not unlike the way we tend to talk to the tiniest members of our own species.
“Songbirds first listen to and memorize the sound of adult songs and then undergo a period of vocal practice — in essence, babbling — to master the production of song,” lead study author Jon Sakata, a professor of neurobiology at McGill, said in a statement.
Imaging of the baby birds’ brains also showed that they paid more attention to these face-to-face interactions than to the recordings of more adult-directed sounds — a finding, the authors argued, that may someday be applicable to people with autism and other disorders that can impede language development and social learning. When the baby birds focused on their adult companions, the researchers discovered, the neurons that produced the hormones dopamine and norepinephrine kicked into gear, much more so than when they listened to a recording. For now, the authors plan to investigate whether they can stimulate the same neurons through artificial means — as Sakata explained, “We are testing whether we can “trick” a bird’s brain into thinking that the bird is being socially tutored” — but if the research pans out, it may suggest that the same thing is possible in humans.
In the meantime, the study also fills in a little bit more of what we know about the science of baby talk, or what researchers often call “infant-directed speech.” Past studies have found it stretches across linguistically diverse cultures, and a 2007 study found evidence for baby talk in rhesus macaques — when female monkeys made vocalizations in the direction of their offspring, the noises they made were slower and more musical. Scientists haven’t yet cracked monkey-to-human translation, but it’s kind of fun to imagine that animals, too, spend an inordinate amount of time telling their babies that they’re just so cute, yes you are, just the cutest.