A TSRM Snippett

The second stage in analyzing an affordance for an animal is very much a matter (for visually detected affordances) of mathematical optics: to describe the light patterned by an affordance-specific occurrent property and to characterize that patterning in terms of an optical variable, an optical property, that stands in strict correspondence to the occurrent property. (TSRM, 1981, p. 265).

So, in comments on an earlier post, Andrew asked about where it is that TSRM talk about anchoring properties structuring light. It is in section 5. "The specification of intension: affordances and ecological laws", pp. 260-7.  It is rough sledding.

Is this Table Meaningless?

Maybe Andrew should take TSRM to task for this meaningless list of "affordances".

Is this edible? 1

Does the way this stuff structures light provide sufficient information to determine whether this is edible?

How about this?

How about this?

Is this dig-intoable?

TSRM suggest that the structure of light enables you to visually perceive whether a thing is dig-intoable or not.  (Cf. TSRM, 1981, p. 261).  But, do you visually perceive this?  This could be a solid matrix of rock or it could be soft dirt or it could be a thin layer of dirt over concrete.  Can you tell by looking?

Or, run this objection like the others.  Get two boxes.  Fill one with concrete and cover this by a thin layer of dirt and fill the other with dirt.  You cannot visually perceive the dig-intoability of the one versus the other.

The affordance for alight-on-ability

So, take to boxes 3' x 3' x 3' in size. They are physically identical on the outside, but one is rigged with a motion sensitive device so that it will explode if you move near it.

I say they are visually perceived to be the same, but that they afford different things (one affords alight-on-ability; the other does not). So, one does not perceive alight-on-ability.  (Cf. TSRM, 1981, p. 261 for the example of alight-on-overability).

The Perception of Leap-over-ability

So, take to boxes 3' x 3' x 3' in size. They are physically identical on the outside, but one is rigged with a motion sensitive device so that it will explode if you move near it.

I say they are visually perceived to be the same, but that they afford different things (one affords leap-overability; the other does not). So, one does not perceive leap-over-ability.  (Cf. TSRM, 1981, p. 261 for the example of leap-overability).

Future posts 12/13/2010

Today begins a long series of posts on Menary's "Holy Grail". 

What I'll do next on EP is in a bit of disarray.  Andrew's link to the Bingham, Crowell, & Todd, 2004, paper has been very helpful.  The contrast between this and the TSRM paper is striking.  Further reinforcing my preference for psychology that is experimental.

TSRM Bleg #2

Also, have there been any publications anywhere that take up the TSRM strategy for explaining visual illusions?  I have searched the journal Ecological Psychology with "illusion" and "visual illusion" and found nothing promising.  Google scholar doesn't help either.  Nor does PsychInfo. 

I can only say that "To my knowledge, there are no publications that take up the TSRM strategy", but I hate to go with weak claims like that.

What does this mean?

For example, the Müller-Lyer illusion is interpreted traditionally as exemplifying a measurement error. The perceiver sees difference in length between two lines that are equal to some standard of measure, say, a ruler. …  The Establishment is tempted to say that the perceiver … falsely infers from the play of light at the eyes that the two lines are of different lengths when, in fact, they are of the same length.
     What must be assumed to give legitimacy to this claim for perceptual error? The following come quickly to mind: (1) Whatever the proper basis of measurement for describing the figure is, it is one and the same as the basis of the measurement device by which the figure is described. (TSRM, p. 279).

So, I have been wrestling with TSRM for a while now, trying to figure out how they mean to explain visual illusions.  They suggest that cognitivists make assumption (1) above, but I am having a tough time parsing this. I am not sure what they are attributing to cognitivists. Let me explain my confusion.

Suppose, just for expository convenience, that the proper basis of measurement for describing the Müller-Lyer illusion is length, that is, that the Müller-Lyer illusion should be described in terms of length.  Is that one side of the kind of identity claim TSRM are noting?

So, then is length one and the same as "the basis of the measurement device by which the figure is described"?  That doesn't make sense to me.  How can length be a device?  Is there some typo here?

Any help here would be appreciated.

TSRM

"It is painfully obvious, however, that no substantive argument can be built from the notion of kinds, projectibles, laws and counterfactuals given the current state of the art".  (TSRM's "Ecological laws of perceiving and acting, 1981, pp. 254-5)

TSRM's Shark Example 7

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.  (Turvey, Shaw, Reed, and Mace, 1981).

It looks like TSRM think that sharks find food by detecting the electrical fields of fish, but here is what Andrew says they say:

Turvey, Shaw, Reed & Mace (1981)

But Gibson is not denying that information is rooted in physics; he's simply pointing out that the correct level of analysis for the information available to a perceiving organism is ecological. What an organism needs to know is not how far away something is, but whether it can reach that thing - in other words, affordances. You can't get to affordances via the objects of physics, because affordances are personal and contain meaning while physics is neither of these. You therefore have to get to affordances by detecting information about affordances, not units of physics.  (italics added, ref here.)

Here, it looks like Andrew is saying that TSRM think that sharks can't find food (an affordance, right?) by detecting an electric field (a "unit" of physics).  [Actually, this passage seems equivocal to me.  There's the part in the first sentence about Gibson not denying that information is rooted in physics.]

But, then, Andrew also writes this (ref here),

Enter Turvey, Shaw, Reed and Mace. Their reply to F&P is simple: Gibsonian information is suitably constrained (i.e. you can’t just claim any old property can be perceived) and that these constraints are not simply ad hoc, but rooted firmly in a consideration of the physics of the world in which vision evolved. This paper is elegant and clear; in fact its elegance and clarity manage to retrospectively make F&P’s paper worthwhile because it caused Turvey et al to write this.

The constraints lie in the existence of ecological laws. A law describes a set of conditions and the necessary consequence of those conditions (if the temperature of pure water at sea level is 100°C then the water will boil). Laws have scope: the scope is laid out in the set of conditions. Within that scope, the conclusion is necessary, i.e. if the conditions obtain and the scope is correct the conclusion must be the case. Ecological laws lay out the conditions and consequences by which a pattern in (for example) an optic array can specify an object or event in the world; these conditions must relate to the physics of the situation (so ‘shoeness’ is not the kind of property we are dealing with).(italics added)

Now, one must relate organisms to the physics.

So, it looks like there a real dilemma here.  On the one hand, Andrew wants physics ontology to be incommensurable with perceptual ontology, perhaps so that psychology is apparently not reducible to physics.  On the other hand, Andrew wants physics to be commensurable with psychology, so that he can resist the Fodor and Pylyhshyn "trivialization argument".   This seems to me not a mere slip in wording, but the product of distinct theoretical demands.  There are two things, neither of which an EPist, like Andrew, seems to want to abandon. 

Personally, I would think the thing to do is abandon the incommensurability thing.  But, of course, the really big thing to do would be to give up on EP.

TSRM's Shark Example 6

I confess that I have been lazy in pursuing this shark example.  I didn't go right away and read the primary literature to which TSRM referred.  I still have not gotten to the (Kalmijn, 1974) to which TSRM refer, but I did the lazy thing and downloaded what I could from the internet, namely, (Kalmijn, 1971).  It is available here.  Their Figure 2 seems to me important.

Maybe more is less, so that I should let the  Figure 2 speak for itself, but here is one dimension of the results that seems to me to be a problem for TSRM:

They claim that "detecting electric field F" is the same as "taking there to be something edible".  Similarly, I assume, they will take "detecting odorant O" is the same as "taking there to be something edible".  (See panel c.)  But, by transitivity of identity, this leads to the view that "detecting electric field F" is the same as "detecting odorant O".

The cognitivist doesn't have this problem, since "detecting electric field F", "detecting odorant O", and "taking there to be something edible" are different.  The former two can be used as premises in an inference to the last.

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"?

TSRM's Shark Example 4

Sharks electrically detect things to eat and things that impede locomotion (Kalmijn, 1974). An edible living thing such as a flatfish differs in ionic com• position from the surrounding water, producing a bioelectric field partially modulated in the rhythm of the living thing's respiratory movements. A flatfish that has buried itself in the sand will be detectable by a shark swimming just above it. Reproducing the bioelectric field of the flatfish artificially, bypassing a current between two electrodes buried in the sand, invites the same predatory behavior. The shark digs tenaciously at the source of the field departing from the site when the act fails to reveal an edible thing (Kalmijn, 1971). Now there is no intelligible sense in which it can be claimed that the source ought to have appeared inedible if the shark's perception were free of error and if the shark's perception of affordances were direct. 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.
     But what of the shark's actions? Should we not classify them as being in error, as being wrong? After all, the source of the electric field proved not to be an edible thing. Given the nomic relation between 'electric field of type F' and 'edible' there is no intelligible sense in which it can be said that the shark's act of investigating the source of the field was wrong. The wrong action for the shark, given its niche and its appetite, would be not investigating the source of the field.  (Turvey, Shaw, Reed, & Mace, 1981, pp. 276-7).

Consider, now, the final paragraph.  TSRM note (correctly, I believe) that we would not say that the actions are mistaken in the non-standard environments. I think the shark's actions are appropriate given that it takes there to be an edible thing.  But, if it takes things to be that way, then it's taking things to be some way that they are not.  That is, what it takes to be true is, in fact, false.  But, false takings are a problem for the EP approach.

TSRM might claim that, in the non-standard environment, the shark does not take there to something edible.  But, that would conflict with their claim that (a) and (b) are the same state of affairs.

The Shark Cognitivist-Style

In the spirit of the best defense being a good offense, in my other posts on the TSRM account of the shark, Andrew has been hounding me for a mechanistic cognitivist account of what is going on with the shark. I've been avoiding this as I hate to get off topic, but here's a post to reply to Andrew's challenge/question.

It seems to me that there is a mechanistic cognitivist account of the shark implicit in TSRM's account.  The idea is that the shark detects the electric field F, then infers (perhaps on the basis of an implicit assumption that if there is an electric field F, then there is probably something edible) that there is something edible.  By cognitivist lights, inference can be mechanistic, since inference is the kind of thing a computer can do and computers are mechanistic devices.  This is the account TSRM are evidently trying to forestall in the following passage:

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.

So, here is what seems to me to be the lay of the land.  It seems to be common ground to both cognitivists and TSRM that the shark detects the electric field F.  Then, the issue that separates them is how this detection relates to taking there to be a fish present.  The cognitivist answer is that the detection of the field and taking there to be a fish present are related by inference; one is among the premises for a conclusion of the latter.  The TSRM answer is that the detection of the field and taking there to be a fish present are identical.

What I have been challenging is the adequacy of the TSRM account.

Andrew won't like the cognitivist answer, but that's not the same as claiming that I don't have one or that there isn't one.

TSRM's Shark Example 3

Sharks electrically detect things to eat and things that impede locomotion (Kalmijn, 1974). An edible living thing such as a flatfish differs in ionic com• position from the surrounding water, producing a bioelectric field partially modulated in the rhythm of the living thing's respiratory movements. A flatfish that has buried itself in the sand will be detectable by a shark swimming just above it. Reproducing the bioelectric field of the flatfish artificially, bypassing a current between two electrodes buried in the sand, invites the same predatory behavior. The shark digs tenaciously at the source of the field departing from the site when the act fails to reveal an edible thing (Kalmijn, 1971). Now there is no intelligible sense in which it can be claimed that the source ought to have appeared inedible if the shark's perception were free of error and if the shark's perception of affordances were direct. 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.

Fourth, now, it is true, as TSRM note, that in their respective niches, these predicates are nomologically connected.  Thus, we cannot tell by looking at the behavior of fish in their standard niches what they are perceiving.  But by looking at how they behave outside their niches, we see that the fish are keying in on electric fields and red bodies, relying on the nomological connections.  And we can see that in the non-standard environment, when the shark takes something (the electric field) to be an edible thing, it is mistaken.  Similarly, in the non-standard environment, when the stickleback takes something  (a fake fish) to be a male stickleback, it is mistaken.  (Indeed, the non-standard conditions indicate how (a) and (b) are not the same.  (a) is true, but (b) is false.)  This is where EC seems to have trouble.  How can it be that the shark picks up the (Gibsonian) information that there is something edible in the non-standard case, when there is nothing that is edible?

TRSM's Shark Example 2

Sharks electrically detect things to eat and things that impede locomotion (Kalmijn, 1974). An edible living thing such as a flatfish differs in ionic com• position from the surrounding water, producing a bioelectric field partially modulated in the rhythm of the living thing's respiratory movements. A flatfish that has buried itself in the sand will be detectable by a shark swimming just above it. Reproducing the bioelectric field of the flatfish artificially, bypassing a current between two electrodes buried in the sand, invites the same predatory behavior. The shark digs tenaciously at the source of the field departing from the site when the act fails to reveal an edible thing (Kalmijn, 1971). Now there is no intelligible sense in which it can be claimed that the source ought to have appeared inedible if the shark's perception were free of error and if the shark's perception of affordances were direct. 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.

Third, consider TSRM's claim that "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."  This, too, seems to me to be overstated.  "Detects electric field of type F" and "takes to be an edible thing" have different intentional or semantic contents (maybe both have intentional contents that differ or maybe (a) lacks intentional content, where (b) does not), so doing the detecting and doing that taking are not the same state of affairs in a perfectly pedestrian sense that EPists often admit. This is part and parcel of seeing something as an electric field (which would not seem to be an affordance) versus seeing it as an edible thing (which would seem to be an affordance).  In fact, part of the rationale for this shark experiment is to try to disentangle these different intentional objects--these different objects of perception.

Now, maybe there is some sense in which (a) and (b) are the same (which TSRM do not explicate), but there is a crucial sense in which they are different (which I have explicated).  This is why I temper my objection, noting that their claim is overstated.

TSRM's Shark Example 1

Here is TSRM's discussion of a case that is quite similar to the FAPs case, so I'll discuss it here:

Sharks electrically detect things to eat and things that impede locomotion (Kalmijn, 1974). An edible living thing such as a flatfish differs in ionic com• position from the surrounding water, producing a bioelectric field partially modulated in the rhythm of the living thing's respiratory movements. A flatfish that has buried itself in the sand will be detectable by a shark swimming just above it. Reproducing the bioelectric field of the flatfish artificially, bypassing a current between two electrodes buried in the sand, invites the same predatory behavior. The shark digs tenaciously at the source of the field departing from the site when the act fails to reveal an edible thing (Kalmijn, 1971). Now there is no intelligible sense in which it can be claimed that the source ought to have appeared inedible if the shark's perception were free of error and if the shark's perception of affordances were direct. 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.

First of all, this case is much like the stickleback case.  "Detects electric field of type F" is like the "detects red body of type R"  and "takes to be an edible thing" is like "takes to be a male stickleback".  (This is why I place the post here.)

Second, "Now there is no intelligible sense in which it can be claimed that the source ought to have appeared inedible if the shark's perception were free of error and if the shark's perception of affordances were direct"  The claim of "no intelligible sense" seems to me to be a bit strong, but it is probably right that just because a shark can (directly) perceive "edible" does not mean that it can (directly) perceive "inedible".  But, this is largely a misdirection on TSRM's part.  It will still turn out, I shall argue, that in the "non-standard" environments (i.e., in the experimental manipulation), the shark has the false perceptual belief that there is something edible below.  But, how can the shark pick up the information that there is something edible below if there is nothing edible below?  That's what the critic of EP is driving at.