Languages Magazine

Oh Crap. Re-thinking Van Gelder (A Purple Peril)

By Andrew D Wilson @PsychScientists
I have this problem where I like pretty much everything William Bechtel writes except when it pertains to cognitive science. It's annoying because, even when I disagree with him, I think he's worth taking seriously. This was on my mind when I started reading is 1998 paper, "Representations and cognitive explanations: Assessing the dynamicist's challenge in cognitive science."
Oh crap. Re-thinking van Gelder (A purple peril)In this paper, Bechtel critiques van Gelder's construal of the Watt's governor as an exemplar of how cognition could function without representations. I have always liked van Gelder's argument and wrote about it years ago in very favorable terms. I wouldn't say that I don't like it anymore, but Bechtel may have convinced me that one of van Gelder's central claims - that representations don't feature in explanations of the Watt governor - is incorrect. Does this mean that I now think that cognition requires internal representations? No! But, the language Bechtel uses to assess van Gelder's arguments sounded eerily familiar and I realized that the criteria used to label something as a representation are met by...ecological information.

Wait, what? Did I just say that? Yes, let me explain why.

Bechtel summarizes the basic function of representations as follows:

"First, just as in the case of the Watt governor, we need to appeal to such representations to understand how basic cognitive systems, such as the visual system, coordinate their behaviors with their environments" (p 306).

Andrew and I have spent the last 5 years on this blog arguing that ecological information performs this function for perceiving-acting organisms. This means that ecological information solves the major problem that representations were meant to solve for cognition. But this doesn't mean that ecological information does this by being a type of representation (and even if it is a representation, it certainly isn't an internal cognitive representation because ecological information is a real thing out in the world). 

But, listen to this. This is how Bechtel, referencing Newell, defines a representation:

"Designation: An entity X designates an entity Y relative to a process P, if, when P takes X as input, its behavior depends on Y.
There are two keys to this definition: First, the concept is grounded in the behavior of a process. Thus, the implications of designation will depend on the nature of this process. Second, there is action at a distance . . . This is the symbolic aspect, that having X (the symbol) is tantamount to having Y (the thing designated) for the purposes of process P (Newell, 1980, p. 156)."

Furthermore, Bechtel goes on to cite van Gelder's own minimal construal of a representation:

"Any “reasonable characterization” of representation, he says, will be “based around a core idea of some state of a system which, by virtue of some general representational scheme, stands in for some further state of affairs, thereby enabling the system to behave appropriately with respect to that state of affairs” (van Gelder, 1995, p. 35 1)." 

Ecological information specifies dynamic events in the world without being identical to those events (kinematic specification of dynamics). This satisfies Newell's definition. 

This specification enables organisms to coordinate their behavior, as if to the events in the world themselves. Functional behavior wouldn't follow from using ecological information without the "representational scheme" linking information to the world. This satisfies van Gelder.

This is wonderfully subversive. If this argument holds up (a big 'if' as this idea just occurred to me today), it would suggest that representations are central to cognition, but that these representations are completely external to perceiving-acting organisms. 

What's fun about this idea is that it slots in nicely with some very old school arguments for why cognition must be representational. 

For example, here is the classical breakdown of the three levels of a computational cognitive system (taken from Pylyshyn, 1989)

  1. Semantics: the level at which we explain why people do things by appealing to their goals and intentions
  2. Symbols: semantic knowledge is encoded in symbolic expressions. The expressions have parts which also have semantic content. This is the level at which symbolic expressions are manipulated
  3. Biology: For people, all of this must be implemented in a biological system
If we assume that ecological information represents the world, then we have the following three levels, which (mostly) parallel the ones above:
  1. World: the level at which we characterize whether behavior is functional by appealing to goals and intention defined with respect to objects and events in the world
  2. Information: objects and events in the world create patterns in energy distributions that stand in for these objects and events. Information is specific to, but not identical to the objects and events.  Multiple properties in a single event (a person lifting a light box and pretending it's heavy) can create independent kinematic patterns, uniquely specifying both properties (that the person is lifting a light box and that the person is trying to deceive you; Runeson & Frykholm, 1983)
  3. Biology: patterns in energy distributions cause changes to nervous system activity that has functional consequences on behavior in virtue of the lawful connection between information and the world
Pylyshyn thinks we need cognition to be a variety of computation in order to connect psychological activity with the physical world:
“If the knowledge-level description is correct, then we have to explain how it is possible for a physical system, like a human being, to behave in ways that correspond to the knowledge-level principles while at the same time being governed by physical laws…At present there is only one candidate explanation for how knowledge-level principles can be causally realized, and that is the one that builds on the set of ideas going back to the insights of Boole, Hilbert, Turing, Frege, and other logicians. It says that knowledge is encoded by a system of symbolic codes, which themselves are physically realized, and that it is the physical properties of the codes that cause the behaviors in question” p 61
The idea of ecological information acting as a type of external representation also slots nicely into this idea. Working through the quote above, ecological information can explain how a physical system can behave functionally (i.e., at the knowledge level) and the way it does so is consistent with physical laws. Properties of the world (including exciting social properties) create patterns in energy distributions - this serves the function of encoding knowledge in symbolic codes that are physically realized. The physical realization of information (structure in energy) causes changes in nervous system activity, which consequently affects behavior.To be honest, I have no idea what to make of this argument at the moment. I'm not jumping off the wagon and saying that cognition is computation. But, I do think that ecological information meets some minimal definition of a representation. And, this opens up the possibility that ecological information might fit into discussions about what general problems representations are meant to solve. For some of the early work, a key problem representations were addressing was how physical systems like people could behave functionally with respect to the world. Where the classical account really collapsed was in trying to explain how the symbols (which it's now more fashionable to refer to as representations) get their content. I'm not going to get into this massive debate at the moment, but suffice it to say, this hasn't been an easy problem, and recent attempts to ground the symbols in perception haven't fully addressed it. This problem disappears if representations are external and based on lawful interactions between energy distributions and physical objects and events. Ecological information is meaningful because it is specific to particular physical activities in the world. Another major challenge for the classical account is mapping representations onto neural activity. Everyone assumes that representations are instantiated in the brain, but there is no clear way to identify representations with particular neural activity (see this post for more discussion of this idea). Finding the neural correlates of something isn't the same as knowing the physical makeup and extent of a particular representation. Construing ecological information as a form of external representation solves this problem. Information variables can be precisely defined and identified with specific structures in energy. We can independently verify whether an information variable is present. And, we can independently verify how that information variable corresponds to the world. All of this said, proponents of the classical account wouldn't be happy with the idea that external representations in the form of ecological information could support our behavior. The main reason is that all the criticisms of ecological information from Fodor and Pylyshyn (1981) still apply. I think those arguments can be refuted, but this is for another day!Fair warning, I might be back tomorrow to denounce all of this...Bechtel, W. (1998). Representations and cognitive explanations: Assessing the dynamicist's challenge in cognitive science. Cognitive Science22(3), 295-318.Fodor, J. A., & Pylyshyn, Z. W. (1981). How direct is visual perception?: Some reflections on Gibson's “ecological approach”. Cognition9(2), 139-196.Runeson, S., & Frykholm, G. (1983). Kinematic specification of dynamics as an informational basis for person-and-action perception: expectation, gender recognition, and deceptive intention. Journal of Experimental Psychology: General112(4), 585.Van Gelder, T. (1995). What might cognition be, if not computation?. The Journal of Philosophy, 345-381.

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