Monday, May 1, 2017

Thoughts on Han et al. 2016 + Piantadosi & Kidd 2016 + Lidz et al. 2016

As with our previous reading, I really appreciate the clarity with which the arguments are laid out by H&al2016, P&K2016’s reply, and L&al2016’s reply-to-the-reply. I can also see where some confusion is arising in the debates surrounding this — there seems to be genuine ambiguity in the way terminology is used to describe the different perspectives about the source of linguistic knowledge (e.g., what “endogenous” actually refers to — more on this below). I also really like seeing a clear, concrete example of solving an induction problem that involves fairly abstract knowledge, and using knowledge internal to the learner to do so.

Specific thoughts:

(1) Endogenous: 
It’s interesting that the basic distinction drawn in the opening paragraph of H&al2016 is between domain-general vs. language-specific innate mechanisms, which is different than simply endogenous vs. not (that is, it’s a question of which endogenous it is): “…did the data…allow for construction of knowledge through general cognitive mechanisms…or did that experience play more of a triggering role, facilitating the expression of abstract core knowledge…”

I think the reply by P&K2016 hits on an interesting terminology issue. For H&al2016, endogenous means “internal to the child”; in contrast, P&K2016 seem to go with the more narrow definition of “genetically specified with no external influence”. This then makes P&K2016 question what to make of parents having different grammars than their kids. For H&al2016, I think the point is simply that something internal to the child  — and not solely genetic — is responsible. It’s possible that the internal something developed from a combination of genetics & other data experience, but it’s clearly something that can differ between parents and children. (General point: Just because something’s genetic doesn’t mean it doesn’t interact with the environment to produce the observed result. Concrete example: Height depends on genetics and nutrition.) 

This issue about what kind of endogenous knowledge (rather than simply is it or isn’t it endogenous) is also something P&K2016 pick up on in their reply. They specifically bring up domain-general endogenous factors as possibilities (“differences in memory, motivation, or attention”) and note that the “root cause of the variation may not even be linguistic”. This, as far as I can tell, doesn’t go against H&el2016’s original point. So, it seems like P&K2016 are targeting a more specific position than H&al2016 argued in their paper, though H&al2016’s initial introductory wording suggested that more specific position.

I think L&al2016’s reply-to-the-reply reflects the ambiguity in this position — they note that their paper provides evidence for “endogenous linguistic content”. While the basic reading of this is simply “knowledge about language that’s internal” (and so silent about whether the origin of this knowledge is domain-specific or domain-general), I think it’s easy to interpret this as arguing for the origin of that knowledge to also be language-specific. The final paragraph of L&al2016’s reply underscores this interpretation, as they argue against domain-general mechanisms like memory, attention, and executive function being the source of the endogenous linguistic knowledge. And that, of course, is what P&K2016 (and many others) aren’t fond of. 

(2) Empiricism, P&K2016’s closing: What’s a “reasonable version” of empiricism? My (perhaps naive) understanding was that empiricism believes everything is learned and nothing is innate, which I didn’t think anyone believed anymore. I thought that as soon as you believe even one thing is innate (no matter what flavor of innate it is), you’re by definition a nativist. Maybe this is another example of terminology being used differently by the different perspectives.

(3) One of the interesting things about the experiments in H&al2016 is that the experimental stimuli could be the driving force of grammatical choice. That is, there’s a possibility that people did have multiple grammars before the experiment, but selected one during the course of the experiment and then learned it. This is one way that could happen:

(a) When finally presented with data that require a choice in the verb-raising parameter, participants make that choice. 
(b) Primed by the previous choice (which may have involved some internal computation that was effortful and which they don’t want to repeat), participants stick with it throughout the first test session, thereby reinforcing that choice. 
(c) This prior experience is then reactivated in the second test session a month later, and used as a prior in favor of whichever option was previously chosen. 

If this is what happened, then by the act of testing people, we enable the convergence on a single option where there were previously multiple ones - how quantum mechanics of us…

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