Tag Archives: How infants learn language

How Infants learn language – V

Infants don’t learn language like neural nets do. Unlike nets, no feedback is involved, which amazingly, makes learning faster.

As is typical of research in psychology, the hard part is thinking of something clever to do, rather than actually carrying it out.

[ Proc. Natl. Acad. Sci. vol. 117 pp. 26548 – 26549 ’20 ] is a short interview with psychologist Richard N. Aslin. Here’s a link — hopefully not behind a paywall — https://www.pnas.org/content/pnas/117/43/26548.full.pdf.

He was interested in how babies pull out words from a stream of speech.

He took a commonsense argument and ran with it.

“The learning that I studied as an undergrad was reinforcement learning—that is, you’re getting a reward for responding to certain kinds of input—but it seemed that that kind of learning, in language acquisition, didn’t make any sense. The mother is not saying, “listen to this word…no, that’s the wrong word, listen to this word,” and giving them feedback. It’s all done just by being exposed to the language without any obvious reward”

So they performed an experiment whose results surprised them. They made a ‘language’ of speech sounds which weren’t words and presented them 4 per second for a few minutes, to 8 month old infants. There was an underlying statistical structure, as certain sounds were more likely to follow another one, others were less likely. That’s it. No training. No feedback. No nothin’, just a sequence of sounds. Then they presented sequences (from the same library of sounds) which the baby hadn’t heard before and the baby recognized them as different. The interview didn’t say how they knew the baby was recognizing them, but my guess is that they used the mismatch negativity brain potential which automatically arises to novel stimuli.

Had you ever heard of this? I hadn’t but the references to the author’s papers go back to 1996 ! Time for someone to replicate this work.

So our brains have an innate ability to measure statistical probability of distinct events occurring. Even better we react to the unexpected event. This may be the ‘language facility’ Chomsky was talking about half a century ago. Perhaps this innate ability is the origin of music, the most abstract of the arts.

How infants learn language is likely inherently fascinating to many, not just neurologists.

Here are links to some other posts on the subject you might be interested in.





How infants learn language IV

The intellectual capacities of infants learning language have always amazed those studying it. The ingenuity of researchers is on display as they figure out how to interrogate a non-verbal infant. In this case it’s figuring just what to study.

One feature of language is the use of the same sound to mean different things, particularly emotional things. Think of how many emotional states there are in cool — neutral as a description, positive, negative as an emotional descriptor. I’m sure you can think of better examples. The fancy word for this is functional flexibility — e.g. when a single vocal category expresses a variety of emotional states on different occasions.

So when do infants develop this? Surprisingly early according to [ Proc. Natl. Acad. Sci. vol. 110 pp. 6318 – 3623 ’13 ] The authors measured functional flexibility by looking at the infants faces as they made different sounds. It begins very early (3 – 4 months). Functional flexibility is found with squeals, vowel-like sounds and growls (but not by laughing or crying which are always taken to the same emotional state — I’m not sure how you’d take them to mean something else.). It appears far earlier than syntax, or word learning.

Prosody is the melody of speech. When we talk the rhythm of our words changes along with their pitch. It’s why I love to hear people from the (Caribbean) islands talk. Their speech is incredibly musical. It is invariably lost after severe head injury, and one good prognostic sign is when it starts to come back.

I don’t know if anyone has studied when infant babbling acquires prosody, but it’s present long before speech.