Semi-Daily Journal Archive

The Blogspot archive of the weblog of J. Bradford DeLong, Professor of Economics and Chair of the PEIS major at U.C. Berkeley, a Research Associate of the National Bureau of Economic Research, and former Deputy Assistant Secretary of the U.S. Treasury.

Tuesday, August 22, 2006

The Blue Car Is the Red Car

Once upon a time we had a red car--a red two-door 1987 Acura Integra without air conditioning that we bought in the spring of 1988. We called it "the red car." After thirteen years we replaced it with a blue four-door 2000 Acura Integra with air conditioning. And for the first couple of months we had it, we would occasionally and accidentally (whatever that means) refer to it as "the red car"--even though we knew full well that it was the blue car.

You see, I would argue, the neural circuits were well-engraved: an Acura Integra, the smaller of our cars, the more responsive of our cars, the non-station wagon--the features of the blue car were nearly identical to the features of the red car, so when our brains grasped for a verbal referent they had a good chance of picking the standard phrase we used for the red car. And, of course, neither of us had any trouble understanding what the other meant by the phrase "the red car."

Last week, for the first time in a decade, we drove past the dealership where we bought the red car. And last week--for the first time in five years--we both used the phrase "the red car" when we meant "the blue car."

Thus it seems only natural to me to think that Jerome Feldman is right when he claims, in Jerome Feldman (2006), From Molecule to Metaphor: A Neural Theory of Language (Cambridge: MIT Press: 0262062534), that it is time to try to study human language seriously by starting with the observation that language is produced and controlled by human brains active in the world, each of which has perhaps 100 billion neurons with a thousand connections and millisecond response times--a massively-parallel array of processors in a form almost totally unlike the traditional architecture of all of our electronic computers (except possibly for Google itself).

This may be a bad bet. 100 billion neurons will surely have powerful and remarkable emergent properties that cannot be easily predicted from the behavior of any one of the neurons. Perhaps language is that sort of emergent property that is effectively wetware-independent. But I don't think so. I think it is a very good bet. And Jerome Feldman takes us all on a very interesting and wild ride through the subject.

Highly recommended.

And when Jerome Feldman tries to explain how so much of our high-level metaphorical thinking is grounded in primary metaphors of our immediate physical experience, he can only do so... metaphorically. His discussion of the event structure metaphorical complex contains the sentence: "Difficulties are impediments to motion." Impediment. You can see the Latin roots im- and ped-: an impediment is something that keeps you from footing it. Your impedimenta is your luggage that you have to carry on your journey, but that makes the journey difficult.

p.87: Let's look at how long it takes, on average, to do one of these perception-reaction tasks.... How fast can you engage the brakes after seeing an obstacle in your path? It takes about half a second.... This kind ....of calculation can help us understand some basic facts about how the brain computes.... [T]he time for each of the basic processes of neural signalling and firing is about one-thousandth of a second.... Let's compare this with the average human reaqction time of half a second.... The reaction time includes the time for the image information to get from the eyes back to the brain and the time for the motor signals to reach the muscles and contract them. This doesn't leave very much time for the brain to do whatever processing is needed to decide which button to push or whether to slam on the brakes.

If we think of each neural action as one computing step, then our brain is able to compute the reaction in around 100 steps. By way of contrast, computer programs... take many millions of time steps to recognize an image. This discrepancy is one of the main factors leading computer scientists to conclude that neural computation is radically different from ordinary computation....

Earlier work had shown that you could both improve the speed and reduce the probability of error in such a visual reaction task by having the subject hear the target word around the time the image was flashed... the general phenomenon of priming.... When you are planning to buy a care, you are much more likely to notice similar cars....

The psychological literature is filled with discussions of priming, spreading activation, and related ideas. There is usually no specification of how mental connections and spreading mental activation map to neural connections and neural firing. Bridging this gap is an important goal of this book...

p. 141: For embodied cognitive science, any computational-level formalism must be effectively reducible to the connectionist level and thus to brain mechanisms. Computational-levbel descriptions may fail to capture several key neural properties, including massive parallelism, robustness, spreading activation, context sensitivity, and adaptation and learnings. As in all science, the trick is to have levels of description that are mutually consistent, with each facilitating different kinds of reasoning...

p. 200: A general theory elaborated by Joseph Grady in 1996 suggests that the metaphor system is grounded in the body in terms of "primary metaphors." In each primary metaphor, such as affetion is warmth, an experience brings together a subjective judgment... and a sensory-motor occurrence.... For this metaphor, such an experience might be cuddling up to a parent. Such correlations often show up in language.... Affection is warmth.... Intimacy is closeness.... Important is big..... Happy is up.... Bad is stinky.... More is up.... Help is support.... These primary metaphors allow one to express a private internal (subjective) experience in terms of a publily available event; this is one crucial feature of metaphorical language.... Largely universal, primary metaphors provide the grounding for much of the metaphor system.... From our neural perspetive, primary metaphors can be seen as a normal consequence of associative learning... neurons that fire together, wire together....

Causes are forces. States are locations (bounded regions in space). Changes are movements (into or out of bounded regions). Actions are self-propelled movements. Purposes are destinations. Means are paths (to destinations). Difficulties are impediments to motion. Expected progress is a travel schedule; a schedule is a virtual traveler, who reaches a prearranged destination at a prearranged time. External events are large, moving objects. Long-term, purposeful activities are journeys.

p. 273: The core questions in dispute can thus be expressed succinctly: (a) Are formal grammar rules expressed in the brain? (b) Is grammar independent of other brain structures? (c) Is there some special genetic encoding specifically for grammar? The language wars are fought between people.. portraying grammar as a special ability and... [those] suggesting that it is part of our general intelligence.... Neither side in this battle... worries explictly about the details of how language and thought are processed in the brain. The linguists do analysis of language as such, and the PDP connectionists focus on learning rules. By keeping the issues narrowly focused, both sides are able to pursue their arguments without dealing with questions that would be compelling from any broader perspective.... [C]onsider walking, or even better, dancing. Dancing is clearly learned and can be described by rules. Dancing appears to exist in all cultures and can be learned without formal instruction.... There may well be a human proclivity to dance--a dancing instinct. Suppose we recast issues a-c for dancing: (a) Are formal dancing rules expressed in the brain? (b) Is dancing independent of other brain structures? (c) Is there some special genetic encoding specifically for dancing? These questions don't seem to make a whole lot of sense, do they?... [N]one tells us much about how cdancing is actually carried out and learned....

For different reasons, both sides in the language wars reject detailed operational theories. From the PDP general learning position, the only interesting issue is learning from a blank slate.... The fact that the brain has a great deal of elaborate structure before learning begins is ignored....

The extreme believers in innate, autonomous, rule-based grammar can ignore any conflicting biological evidence because of their conviction that neuroscience is not nearly developed enough to be taken seriously.... Chomsky... in... 2003.... "When people say that the mental is the neurophysiological at a higher level, they're being radically unscientific. We know a lot about the mental from a scientific point of view. We have explanatory theories that account for a lot of things. The belief that neurophysiology is implicated in these things could be true, but we have very little evidence for it. So, it's just a kind of hope; look around and you see neurons; maybe they're implicated."... The scientific path to truth [according to Chomsky]... is formal linguistic analysis. If neuroscience is incompatible with this formal analysis, neuroscience must be wrong. The same belief system provides a rational for ignoring inconvenient results from psychological experiments.... These are said to reflect only linguistic performance.... The deep questions concern linguistic competence and can only be addressed by the orthodox methodology of formal grammar...

p. 317: They key to understanding grammar acquisition is not the famous poverty of the stimulus... but rather the opulence of the context. The child comes to language learning with a rich base of conceptual and embodied experience as well as a supportive social environment. Words and rules that describe this experience can be learned without formal training, although not without years of focused effort...

p. 330: My personal favorite among the recent books is Looking for Spinoza by Antonio Damasio (2003). Damasio tries to relate the latest biological and clinical findings to subjective experience with impressive results. As with all current explanations, even if every detail in the book were exactly right, it wouldn't resolve the big question. We simply don't yet have a way to pose the question of subjective experience in a way that could yield a scientific answer...

0 Comments:

Post a Comment

Links to this post:

Create a Link

<< Home