A blog about problems in the field of psychology and attempts to fix them.

Friday, October 7, 2011

Beyond the Brain: Embodied Minds and Descriptive Mentalism

Continuing coverage of Beyond the Brain, by Loise Barrett.

William James and John Dewey claim that "things are what you experience when you experience those things". Pretty similarly, a basic way of explaining Charles Sanders Peirce's Pragmatism was that "things are what things do" (e.g., to be a 'vector' is to do what vectors do, to be a 'bigot' is to do what bigots do). Both of these ideas were alive and well during the berthing years of Behaviorism, and at least a few of the early behaviorists 'got it' (though notably not Watson). In more modern terms, you could call the resulting synthesis Descriptive Mentalism.The thirty-second version is: A descriptive mentalist asserts that mental terms are, first and foremost, descriptions of behavior, not explanations for behavior. For example, to say an animal intends to do X is to describe something about the way the animal is acting. To connect this approach more explicitly with W. James and Dewey (and Gibson)... If we can identify the things that we experiencethe things that we are attuned towhen we experience an animal as "intending", then we have identified what "intention" is.  

While there will be several posts on this blog trying to explain descriptive mentalism better, here I hope to show how adopting such a view could have helped Barrett.  

Embodied Minds

As I mentioned previously, Barrett does not give the most hardline presentation of embodiment you can find, and overall that is a strength, making the book much more accessible. However, it is still worth noting a few places where Barrett struggles, and a more aggressive view on embodiment could help.

I first started feeling like things could be improved in the early chapters where Barrett was berating our anthropomorphic tendencies. I'm not a fan of undue anthropomorphism, so I was very sympathetic with these chapters. (My post-doc adviser, Nick Thompson, also wrote on these issues, including here and here). In these early chapters, Barrett made the intriguing argument that it is acceptable to anthropomorphize when talking about ultimate causes of behavior, but not when talking about proximate causes. Thus, she argues that it is acceptable to argue that a given animal 'wants' to find a good mate, if one means only that natural selection has favored ancestors that found good mates. But, she argues, it is not acceptable if one means that the animal currently 'wants' to find a good mate, because "we simply don't know what goes on in the female's head" (p. 9).

For the record, I really like the distinction between the ultimate and proximate usage of the mental terms. However, I was instantly concerned about the claims that a) mental things are 'going on in the head' and b) that they are unknowable. If we are to fully embrace embodiment, then (contra 'a') mental things are not merely brain things, and in any case we should recognize that (contra 'b') anything a body does is (at least potentially) observable, as are the relations between behavior and environment. Thus, in one way or another, those in favor of embodiment should believe that minds, mental processes, etc., are observable. Barrett seems close to embracing this in other parts of the book, but always backs off the final conclusion.

Parts where Barrett Backs off to Early

Most of the Beyond the Brain is focused on what humans, animals, or robots can do. In the places that I found awkward, Barrett often seemed most focused on what creatures under study were not doing.

        An Animal Example
One example comes at the end of the excellent chapter covering research on the predatory behavior of the Portia spider. Barrett concludes by saying (among other things):
Far from demonstrating that spiders plan a detour route in an insightful way, these detailed and careful experimetns reveal that the spider follows a simple rule... It is this set of simple mechanismsnot insightthat allows them to reach the prey... (p. 70)
True enough. The research is against the idea that the spider's flexible behavior is explained by "insight." However, a focus on such issues takes us away for a simple description of the actual motivation of the spider; it takes us away from the question "What is it that the spider is trying to do?" At least some of the experiments gave us great insight into this: The spider is trying to find a path towards it prey, which involves searching for different types of paths in a particular order, and, because the spiders eyes are attached to it's inflexible head, such searching entails moving its body in particular ways. I don't mean this dualistically, of course, but simply as a description of the spider's behaviors relative to their circumstances. Such mental terms can be used in a simple, and objective description of the organism's behavior... once we have the necessary experimental evidence.

      A Robot Example
This problem also came up in some of the discussions of robots. For example, Grey Walter's 'turtle' robots could do some pretty cool things. Among other things, they had light sensors connected with their wheels such that they moved towards lights, until the sensed light got too bright, and then they would move away. This allowed them to do all sorts of impressive things, such as recharge themselves and some things that looked a lot like mirror self-recognition. Barrett tells us that if we didn't know how these robots "were put together, then it would be natural to attribute more internal complexity than was warranted, as well as to overestimate the cognitive demands of the tasks that they could perform." (p. 47) True enough. But notice that the lack of internal complexity and the minimal cognitive demand should not lead us to neglect what the robots are doing. Among other things, they are seeking out a certain light level. I don't mean this dualistically, of course, but simply as a description of their behaviors relative to their circumstances. 

      A Human Example
I detected similar awkwardness in the section talking about infants looking longer at face-like stimuli. In the end, the focus was on what infants are not doing (they do not discriminate faces from all  possible face-like stimuli). It would have been nice to see a focus on the mechanism that leads infants to prefer faces in normal circumstances (e.g., any world without people built like Picasso paintings). 

Motivation vs. Selection Pressure
Barrett's distinction between the use of mental terms to identify proximate causes vs. ultimate causes is good. However, motivation is a proximate thing. The ability to distinguish functional cause from immediate motivation was one of the great gifts from the classic ethologists. For example, they determined that the goals of certain female fish were to mate with male fish with long tails. They determined this through many experiments, including experiments where they glued artificially long tails onto the male fish. When they made conclusions about what the female fish were doing, they were not merely commenting on the selection pressures that had favored that fish's ancestors, they were commenting on the way that now-living fish behaved across a variety of current circumstances. It took experimental manipulation to determine the female fish's motivation, but it did not take special access to the fish's brain, nor anything else that a third-party observer couldn't plainly see under the right circumstances.

Parts Where Barrett Pushes Harder

Despite those examples, in other parts of the book Barrett clearly has urges to go in the direction I suggest. She points out, for example, that:
The "social intelligence" of primates is, in essence, based on visually guided... action in the world. Our tendency to see other creatures in terms of ourselves rests largely on this basic primate tendency to respond to certain forms of social stimuli. (p. 36)
Barrett also hints hinted at similar ideas earlier, when arguing that natural selection has favored animals that sometimes false-positive to the presence of life, "so that we can pick up on the essential elements that are needed to make us think that a small red triangle is alive." (p. 26) In other words, having "social intelligence" is nothing-other-than responding to a certain set of environmental happenings that most organisms do not respond to. 

Probably the one part of the book where Barrett embraces a descriptive mentalist position most clearly is towards the end of her discussion of cricket mate choice. Basically, you might think that the "mate choice" process requires a lot of brain power, and a dualist might even claim that as a necessary implication of the term "choice". However, as is clearly demonstrated in the book, the female cricket successfully arrives at one of the many available mates largely by virtue of her body structure, and not by virtue of elaborate brain power.

Now, a dualist faced with such evidence might try to argue that the researchers have proven that the female cricket doesn't "choose" at all. But contrary to that, Barret's concludes:
Choice emerges from the kind of simple auditory steering process... these results again reinforce the idea that the "steering" mechanism and the "picking-out" mechanism are one and the same thing. It is the rhythm and temporal pattern of the male song that simultaneously "steers" the female to its source, and "discriminates" the male's chirps from the background. (p. 55)
Note especially the first two words: "Choice emerges." The hidden implication of this claim is that we all, when watching the cricket, can see that the cricket chooses... we can see that a choice has been made, that potential mates have been discriminated... and no evidence about the mechanism by which such a process occurs can undo that observed truth. Contra the dualist's claims, the mechanism isn't what determines if choice has occurred, the pattern of behavior in particular environments is "choosing".

This is a better attitude, and I wish I had seen it more aggressively in the rest of the book. Ultimately, if those of us supporting embodied cognition cannot talk about minds, we'll get booted out of psychology. The challenge is how to explain to our colleagues, and perhaps eventually the general population, that we are talking about mental processes.


Dear readers,
It was actually a lot harder writing this post than I thought it would be. Are there parts where more information is needed, or where things fall apart? Are there additional implications I have missed, or implications I have exaggerated? Any help would be appreciated.


  1. Eric -

    Because it turns out (unbeknownst to me prior to reading the post, of course) that I'm a "descriptive mentalist", I have no critical comments - I'm in almost total agreement with the post as written. But I do have some related questions.

    In the last paragraph you address the need for DMs to be able to "talk about minds", in particular (I gather) to emphasize to non-DMs that "describing" observed behavior is one way of doing that. Although I don't yet fully appreciate the distinction that some make between "describing" and "explaining", it seems likely a useful one. So, I'll postulate that behind a "description" of an organism's activities in an environment expressed in a behavioral vocabulary is - potentially - an "explanation" of those activities expressed in a physiological vocabulary. Then, while I agree that it might be useful (and arguably politic) to include mentalistic terms in the former vocabulary, I suspect that including them in the latter just confuses. Any reason not to make that distinction?

    FWIW, I'll add that for some time now I've been trying to avoid mentalistic terms when thinking about explanations of behavior. So far, so good.

    In an essay from the collection by Donald Davidson ("Subjectivity-Intersubjectivity-Objectivity") mentioned previously, Davidson poses the "swampman" thought experiment. In essence, it postulates that Davidson (DD) is instantaneously decomposed into his "molecular" components (I'm not sure why it's not some lower level of "fundamental particles', although I don't think it matters) and reassembled as before into a clone referred to as "swamp-DD" (S-DD). Davidson's claim is that though physically - and behaviorally - identical to DD, S-DD is not psychologically identical because S-DD has no history. Eg, S-DD interacts with DD's friends just as DD would have but doesn't actually "re-cognize" them, never having met - "cognized" - them before.

    This follows from Davidson's claim that many (all?) details of an individual's mental states are determined by the individual's specific history, which I buy (in fact, it seems obvious). But I don't get the claim that this history disappears in the disassemby-reassembly process. My (tenuous) understanding is that memory (in general) is implemented by brain plasticity. If so, then our individual mental (psychological) histories are "stored" in neuronal structure, which presumably would be reproduced intact by the reassembly process. Or in a (hypothetical) "pure" (ie, mental-term-free) psychological vocabulary, the explanation for S-DD's behavior being the same as DD's would be that the learned (stimulus induced sensory-neuron activity pattern, motor-neuron responsive disposition) pairs that dictate DD's responsive behavior would be reconstructed in S-DD.

    An Internet search of articles referring to "swampman" yielded several accepting Davidson's claim re physical-psychological but none disputing it. In the essay, Davidson introduces the thought experiment to refute a Searle claim of physical-psychological state identity, but there is a question as to exactly how Searle's "psychological states" are being defined. This seems to strongly suggest that my assessment is wrong, but then I have to ask: if not via brain plasticity, what could be the mechanism by which individual history is originally captured? And whatever the (presumably physical) mechanism, why isn't it maintained across the disassembly-reassembly process?

  2. Charles,
    Two thoughts:
    1) The physical causality of mental events issue becomes very tricky. I'll try to post on that separately soon, because I'm not sure I am skilled enough to give you a succinct answer here. Maybe another reader can chime in.

    2) I agree with you that the swamp-man example is weird. I am envisioning something like a Star Trek teleporter. I'm not sure why some things about Davidson (e.g. his tendency to call his friend "Bill") would transfer to swamp-Davidson, but that other things about Davidson (e.g. his memory of Bill) would not transfer. The distinction seems so obviously arbitrary... Davidson must have had a very good argument to get people to agree with him.

    My only guess is that he is arguing that it is impossible for swamp-Davidson to "remember" Bill, because, in fact, swamp-Davidson has never encountered Bill before. That would be a coherent argument, but it would not be very interesting... unless Davidson does a bit of a shuffle between technical and intuitive usage of his terms. In which case the problem could be made to seem very provocative.

    This is all pure speculation though. Anyone out there able to confirm or deny my intuition?