Tuesday, November 2, 2010

TSRM's Shark Example 5

In the niche of the shark 'an edible thing' and 'electric field of, say, type F' are nomically related. To predicate of the shark (a) 'detects electric field of type F' and (b) 'takes to be an edible thing' is not to refer to two different states of affairs, one (viz. (b)) that is reached from the other (viz. (a)) by an inference. Rather, it is to make reference in two ways to a single state of affairs of the shark-niche system. The linking of (a) and (b) is not something that goes on in the "mind" of the shark, as the Establishment would have it. The linking of (a) and (b) is in the physics of an ecological world, namely, that system given by the complementation of the shark and its niche.
Fifth, it seems to me that the TSRM strategy is misguided.  The cornerstone of their reply to the shark case is that if P and Q are nomologically related under normal conditions, then detecting P and taking to be Q are the same.  But, the strategy seems to me to be misguided.  In general, one does not want the detection of P to identified with taking to be whatever P is nomologically connected to.  So, there is a nomological connection between being a triangle and being a trilateral, but does one want to say that detecting a triangle is the same as taking something to be a trilateral?  There is a nomological connection between being a tuna and having mass, but does one want to say that detecting a tuna is the same as taking something to have mass?

There is probably some  implicit condition that P is uniquely nomologically connected to Q or that Q is the only thing in the natural environment that is nomologically correlated with P.   So, on how about P = "detects sunlight" and Q = "takes there to a thermonuclear reaction taking place about 93,000,000 miles away"?  How about P = "smells blood in the water" and Q = "takes there to be alpha hemoglobin present"?


  1. Actually these are good points. They get you into issues of learning, which is a key part of all this for sure. It's not a focus of the TSRM paper, but learning what to perceive was what EJ Gibson (JJ's wife) was studying and all that ran alongside JJ's main programme.

    Your examples: P is information, Q is an affordance. You don't get to 'take there to be a thermonuclear reaction' from 'detects sunlight' because the former isn't an affordance and thus doesn't impinge on any organism niche in any sensible way. The latter is a better example, although it makes no sense to express the affordance in terms of alpha hemoglobin. Overt behaviour is in the mix; perceptual learning is intimately connected to action production.

  2. Well, TSRM don't place this information/affordance stricture on the example in that section ...

  3. Really? The whole paper is about specification of affordances. This section is about perceiving the 'edible-by-a-shark' affordance. What did you think P & Q were?

  4. Yes, but one needs clues about apparatus to deploy in what contexts. There ain't none here.

  5. I thought P was a physical property. Electrical fields are physical, right?

    But, Gibsonian information is not a part of physics, right?

    So, it looks to me as though they can't be presupposing that the field is information.

  6. The information is a spatial-temporal pattern carried by the energy array, in this case the electrical energy. Or did you think Gibson was claiming information wasn't implemented with physical stuff?

    A physicist would analyse the field into physical properties (voltages, currents, whatever else you get in electrical fields). An ecological psychologist would analyse the field into the spatial temporal pattern which specifies 'edible-by-a-shark'. The latter description is not a part of the scientific abstraction that is physics; rather, it's part of the scientific abstraction that is ecological information (optics for vision, etc). Same stuff, different analysis, and the physics analysis is not 'more real' than the ecological analysis, especially not for a theory of perception.

  7. Well, again TSRM never say *information* in the electrical field. They just say electrical field. And, they don't say "edible-by-shark". Had they said the latter, they would be more easily interpreted as writing about affordances.

  8. But, Kalmijn also does not say that the shark's respond to information in the electrical field; he says sharks respond to the electrical field. The logic of his experiments are to find what the sharks are detecting and he says electric fields and odorants. Not information in electric fields and odorants. It would be great if TSRM, or some EPist, were to dissociate these two and show that the sharks respond to Gibsonian information, rather than the electrical fields.

  9. I agree; there's an empirical study waiting to happen. But the point of the TSRM paper isn't to convince you with data; it's to lay out the theoretical basis for the empirical programme that will (well, will try to :) So yes it's incomplete, but that's also not really a point against it.

    You shouldn't be so literal; just because they didn't say affordance and information right there doesn't mean that's not the issue, because those are THE issues for EP, and it's all the way through the paper.

    Also Kalmijn isn't an ecological psychologist so how he talks about his data is up to him.

  10. But, the EPists are among the most fanatical about using the correct jargon of any psychologists I've ever read. Deviations are not tolerated without comment. So, what's good for the goose ...

    TSRM are trying to use Kalmijn's results to their benefit. I'm indicating that they cannot in the sense that Kalmijn does not show that sharks respond to information in electric fields, they apparently respond to electric fields. This is not a matter of how one talks about the data; it is a matter of what the data is. It's not what you say that TSRM think it is.

  11. The whole paper is about affordances and information, though.

    Although, in fairness, maybe they don't use those words right there precisely because they don't have a data driven ecological analysis for this specific example and thus want to keep it an example of the kind of thing that goes on rather than a specific eco-psych experiment.

    Turvey is many things, but careless about his choice of words isn't one of them.

  12. Well, I've not read the whole paper, but section 3 does not seem to me to be about affordances and information. I'm willing to contextualize arguments, but the proposal that electrical fields versus information in electrical fields seems to me not to be born out by the data.

    So, if Turvey is very careful in his word choice, then when TSRM don't use certain words, then I take them at their word. They need to say what they mean and mean what they say.

    So, the weight of the evidence from Kalmijn seems to suggest reading the claim as sharks detect electrical fields, rather than information in electrical fields. Second, literal reading of the immediate text supports this. This not bad evidence in favor of my reading.