As you’ve probably noticed, very young infants would rather listen to human speech than almost anything else! But recently, we’ve discovered that listening to speech also plays an important developmental role: it gives infants a big cognitive ‘boost.’ We’ve found that when infants listen to human speech, they are more successful at cognitive tasks, like detecting commonalities among distinct individuals (e.g., Fido, Spot and Sparky) and forming a category (e.g., dog). We’ve also discovered that for 3 and 4 month-old infants, speech is not the only sound that boosts cognition: surprisingly, listening to vocalizations of non-human primates (e.g., blue-eyed Madagascar lemurs) offers the same cognitive boost as human language! But babies learn fast. By 6 months, lemur vocalizations no longer ‘boost’ infant cognition. At this point, infants have tuned in specifically to human speech.
We are pursuing this intriguing line of work, asking:
(1) What is the range of sounds that initially support infants’ cognition? Do mammal vocalizations or birdsong also boost early cognition?
(2) How does infants’ experience help them to ‘tune in’ to human language and ‘tune out’ other sounds?