Questions on Plunkett et al.

Hi all,

I just got an email with questions on the article for tomorrow - just in case it helps other, here are the Qs and As:

Q: I am confused on what "out-of-category" means and what a novel or novelty label is.

A: Okay, the first thing to think about is how the authors define the categories for the kids. For example, in experiment 1, they define a "broad" category, that encompasses *all* the little animals. In this case, out of category is really at the extremes of the category, either 1111 or 5555, that is, the animals that have really short legs, narrow tail, long neck, and ears close to one another (1111) or really long legs, broad tails, short neck, and ears that are far apart (5555). Basically, babies should be interested in the extreme values of the attributes, because they define unusual animals. To give you a real life example, imagine that you are a baby who still hasn't figured out what defines men and women as categories. Usually, women are shorter than men, have longer hair, and longer nails. But if you hadn't sorted out people into women and men categories, but instead grouped them all into "people" (a broad category) you would find interesting and unusual a woman who is really tall and has long fingernails and hair. Like me last summer!

In experiment 2, babies learn that there are two categories, defined by the fact that their "attributes", their characterizing features, always co-occur: if an animal has longish legs, like 5544 in Fig. 1, then it should also have a short neck, ears far apart and a narrow tail. When you learn two categories, something that is in the middle might be more interesting, because it doesn't quite follow either of the two patterns you'd expect. So, in the people example above, say now you've figured out the correlation of sex, height, hair length, and nail length. Now if you see someone that is kind of masculine and kind of feminine, has hair down to their shoulders, is of average height, and has an average nail length, you go "huh, what are you, a man or a woman?" and you stare at them to try to work them out. On the other hand, you see someone like yourself, and you go "oh, she's definitely a woman, boooring!"

So depending on how you group objects, the same object might be novel or not. In the case of two categories, where extreme values co-occur, something that is halfway might be novel; in the case of one category, then it is the extremes that are interesting.

Now, a label is simply a name. Say that you had worked out that men and women are two categories, but your mom wants you to understand the concept of "person". And so she keeps labeling both men and women with a single name: "Ashley is a person, Dr. Hollich is a person..." Given this label, this name, then you should ignore the fact that you have long hair, and Dr. Hollich doesn't; that your fingernails are longer than his (I think?), etc. etc.

Questions from Friday

All great questions! I've answered the "business" questions below, and for the theoretical ones, I'll post just the questions for a few days, so that you can add follow-up questions or comments. I'll come back to them next week and add my own thoughts about them.

You said we only worry about foreign _speech_ exposure, but what if we had a CODA (Child of Deaf Adults) and both parents were deaf and the child stayed at home. Would we get accurate information from them or how would that work.

That's a great question! In similar cases in the past, we've brought the baby in anyway and made a note of it. Although it's likely that this child will not get as much speech exposure as other kids, all of their exposure is to English, and thus they count as "non-contaminated". (Sigh... so sad to be bilingual and say things like that...)

What will the schedule look like for the Mondays we will open the lab for scheduling purposes?

Another good question! I posted a tentative schedule below our regular one. Schedule babies half hour after the first person comes in, and half hour before we close. That would be 9-4:30 on 10/20 and 10/27, and 10-4:30 on 11/3.

Social interaction and language

I know that language and social interaction aren't connected directly, but may be connected by an "X" factor. What are some ideas of what this "X" factor might be?

Can we talk more about prototypes and how do you screen candidates for those studies?

How can prototypes be perceptually based?

What is being "statistically stable?" How does language become statistically stable in children?

How do categories in vision that I learn in psych differ from speech categories?

Hint: Go back to our summary of category types from Friday (slide 6), and try to fit examples of the vision categories you've seen into our classification.

Calling cellphones

I was wondering, today in lab we had a teenaged son answer the phone when trying to call a baby and he gave the moms cell phone number. We didnt know if we should call that number or not so we have not yet. Just wondering!?

Returning to the question of species-specificity

Hi all,

I wanted to leave a link to an excellent article which discussed how studies of non-human animal perception contribute to our theories of human perception: http://www.psy.cmu.edu/~lholt/publications/KluenderLottoHolt2005.pdf

Today's article

First of all, I'd like to thank you all for being so involved on today's topic - it was very exciting to see such profound interest and to hear such shrewd questions!

On to business now: I'll post the questions here, grouped into general topics, and hopefully we'll get to them all next Friday although most of them are so fundamental that decades of research have only begun to scratch the surface. Please feel free to post follow-up questions and comments!

Kuhl 2004: Neural commitment

As we get older, does our capacity for neural commitment lessen or does it only lessen for our ability to acquire language?

How does the neural commitment change/develop? Is this directly related to the critical period or are they different?

Kuhl 2004: Perceptual abilities

Why can't monkeys talk if they can perceive a little better than humans?

Are children's ears attuned sharper than adults to hear subtle acoustic changes?

I'm not very clear on the topics that include a continuum of sounds and why babies can distinguish these sounds but outgrow the ability

Kuhl 2004: Statistical distributions

Can we go over statistical distributions together sometime?

I don't understand question 11 ("What does Kuhl mean by infants tracking “statistical distributions”? [Hint: Do Japanese-learning infants hear both /r/ and /l/? How is Japanese- and English-learners’ input different?]")

Kuhl 2004: Categories

I had a difficult time understanding the perceptual magnet effect.

I'd like clarification on the perceptual magnet effect and prototype learning.

One of the questions asked about prototype perception, but I don't understand it. What is prototype perception?

Can you explain categorical perception? I am confused by the term.

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