Tuesday, June 7, 2016

Listening to Speech Has Remarkable Effects On a Baby’s Brain

Imagine how an infant, looking out from her crib or her father’s arms, might see the world. Does she experience a kaleidoscope of shadowy figures looming in and out of focus, and a melange of sounds wafting in and out of hearing?

In his Principles of Psychology (1890), William James imagined the infant’s world as ‘one great blooming, buzzing confusion’. But today, we know that even very young infants have already begun to make sense of their world. They integrate sights and sounds, recognise the people who care for them, and even expect that people and other animate objects – but not inert objects – can move on their own.

Very young infants also tune in to the natural melodies carried in the lilting stream of language. These melodies are especially compelling in ‘motherese’, the singsong patterns that we tend to adopt spontaneously when we speak to infants and young children. Gradually, as infants begin to tease out distinct words and phrases, they tune in not only to the melody, but also to the meaning of the message.

Once infants utter their first words, typically at around their first birthdays, we can be sure that they have begun to harness the sounds of language to meaning. In my own family, after nearly a year of guessing what my daughters’ babbles might mean, their first words – datoo (bottle), Gaja (Roger, a beloved dog), uppie (a plea for someone to pick her up) – assured me, in a heartbeat, that they do speak my language!

In all cultures, babies’ first words are greeted with special joy. This joy is testimony to the power of language – a signature of our species and our most powerful cultural and cognitive convention. Language permits us to share the contents of our hearts and minds, in ways that are unparalleled elsewhere in the animal kingdom. It is the conduit through which we learn from and about others, across generations and across cultures.

But how, and when, do infants begin to link language to meaning?

We know that the path of language acquisition begins long before infants charm us with their first words. From the beginning, infants are listening, and they clearly prefer some sounds over others. How could we possibly know this? Newborn infants can’t point to what they like or crawl away from what they don’t. But when infants’ interest is captured by a particular sight or sound, they will suck rapidly and vigorously on a pacifier.

Using rates of sucking as a metric, infancy researchers have discovered that, at birth, infants prefer hearing the vocalisations of humans and non-human primates. Then, within months, they narrow their preference specifically to human vocalisations. And toward the end of their first year, infants become ‘native listeners’, homing in with increasing precision on the particular sounds of their own native language.

So, the early preference of newborns for listening to language sets the stage for them to zero in on their own native language sounds and to discover its words and syntax. But only recently did we discover that listening to language benefits more than language acquisition alone. It also boosts infants’ cognition.

by Sandra Waxman, Aeon |  Read more:
Image: markk