Boston University Conference on Language Development: Day 3

This post continues my series on this years' BUCLD. While conferences are mostly about networking and seeing your friends, I also managed to attend a number of great talks.

Autism and homophones

Hugh Rabagliati got the morning started with a study (in collaboration with Noemi Hahn and Jesse Snedeker) of ambiguity (homophone) resolution. One of the better-known theories of Autism is that people with Autism have difficulty thinking about context (the "weak central coherence theory"). Rabagliati has spent much of his career so far looking at how people use context to interpret ambiguous words, so he decided to check to see whether people with Autism had any more difficulty than typically-developing folk. (Note that many people with Autism have general language delays. Presumably people with language delays will have trouble on language tasks. This work focused on people with Autism who have roughly normal syntax and semantics.)

Participants listened to sentences with homophones (e.g., "bat") that were either had very constraining contexts (e.g., "John fed the bat that he found in the forest") or not-very-constraining contexts (e.g., "John saw the bat that he found in the forest"). These sentences were part of a longer story. What the participant had to do was pick out a relevant picture (of four on the computer screen) for part of the story. The trick was that one of the pictures was related to the other meaning of the homophone (e.g., a baseball glove, which is related to a baseball bat). Due to priming, if people are thinking about that other meaning of the homophone (baseball bat), they are likely to spend some of their time looking at the picture related to that meaning (the baseball glove). If they have successfully determined that the homophone "bat" refers to the animal bat, they should ignore the glove picture. Which is exactly what happened. For both typically developing 6-9 year-olds and 6-9 year-olds with Autism. This is a problem for the weak central coherence theory.

Autism and prosody

In the same session, the Snedeker Lab presented work on prosody and Autism. This study, described by Becky Nappa, looked at contrast stress. Consider the following:

(1) "Look at the blue house. Now, look at the GREEN..."

What do you expect to come next? If you are like most people, you think that the next word is "house". Emphasizing "green" suggests that the contrast between the two sentences is the color, not the type of object to be looked at. Instead, if the color word was not stressed:

(2) "Look at the blue house. Now, look at the green..."

You don't know what is coming up, but it's probably not a house.

Atypical prosody is a diagnostic of Autism, at least according to some diagnostic criteria. That is, people with Autism often use prosody in unusual ways. But many of these folk have, as I pointed out above, general language difficulties. What about the language-intact Autism population? Here, the data has been less clear. There is still some unusual production of prosody, but that doesn't mean that they don't understand prosody.

Nappa and Snedeker tested children's understanding of contrastive stress. While typically-developing children performed as expected (interpreting contrastive stress as meaning a new example of the same type of object will be described), highly verbal children with Autism performed exactly opposite: they expected a new type of object for (1) and the same type of object for (2).

A second study looking at given/new stress patterns. Compare:

(3) Put the candle on the table. Now put the candle on the counter.
(4) Put the candle on the table. Now put the CANdy on the counter.

In general, if you are going to re-mention the same object ("candle" in (3)), you don't stress it the second time around. When you are mentioning a new object -- especially if its name sounds similar to something you have already described -- you are likely to stress it. Here, interestingly, the ASD children were just as good as typically-developing children.

Nappa puts these two findings together and suggest that children with Autism have overgeneralized the stress pattern in (3-4) to cases like (1-2). In general, they think stressed words refer to something new.

Other Day 3 talks

There were other good talks on Day 3, but by my notes always get more and more sparse as a conference goes on. Researchers from Johns Hopkins University (the speaker was Kristen Johannes) argued that "differences between child and adult spatial language have been previously attributed to underdeveloped conceptual representations" (this is a quote from the abstract). In particular, children use the preposition "on" in strange ways. They argue that this is because children have impoverished spatial vocabulary (there are a number of useful words they don't know) and, given that they don't have those words, they over-apply "on" not so much because they conceptualize of "on"ness differently, but because they are, literally, at a loss for words. When you make adults describe spatial arrangements without using the fancy adult words they normally use, they end up over-applying "on" in much the same way kids do. (Here I am working from memory plus the abstract -- my notes, as I mentioned, are incomplete).

Careful readers will notice that I haven't written about Day 2 yet. Stay tuned.

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