The New Science of the Mind
Page 10
For now, let us just work with the general idea that a given cognitive process is defined by its functional role-whatever that role turns out to be. Fulfilling a certain role requires certain things to be done, and traditionally those things are regarded as being done by the brain. So, on the traditional, influential way of thinking about visual perception, it is the brain that has the task of transforming a retinal image into visual representation. This is where the idea of environmental embedding comes in. By relying on the environment in an appropriate way, the complexity of what the brain has to do in order to accomplish a cognitive task-that is, in order to fulfill the role that defines a cognitive process-can be reduced.
We've already encountered this general idea in the opening chapter. The complexity of the operations that my brain must perform in order to get me from A to B is reduced by my deployment of an external information bearing structure-a GPS or a MapQuest printout. The complexity of the operations my brain must perform in order for me to complete a jigsaw puzzle-mental image formation and rotation-are reduced by my picking and manually rearranging its pieces. In general, the guiding idea underlying the thesis of the embedded mind is that in accomplishing cognitive tasks, an organism can utilize structures in its environment in such a way that the amount of internal processing it must perform is reduced. Some of the complexity of the task is, thereby, off-loaded onto the environment, given that the organism has the ability to appropriately exploit that environment.
This is, again, an ontic thesis, but whereas the thesis of the extended mind was one of composition or constitution, the thesis of the embedded mind is one of dependence. According to this thesis, some cognitive processes are dependent on environmental structures in the sense that these processes have been designed to function only in conjunction, or in tandem, with these structures. In the absence of the appropriate environmental structures, an organism may be unable to accomplish its usual repertoire of cognitive tasks because the processes it typically uses to perform such tasks work only in conjunction with the missing structures. Or it may be able to accomplish these tasks, but in a less than optimal way-it takes longer, for example, or exhibits a greater frequency of mistakes. One can understand this thesis of dependence in various ways-as a contingent fact about the way (some) cognitive processes work, or as a necessary truth about the essential nature of (some) cognitive processes. But however tight we make the relation of dependence, it is still relation of dependence, not constitution.
The thesis of the embedded mind is an interesting thesis in its own right. However, there is a clear sense in which it leaves the traditional Cartesian picture of cognitive processes largely untouched. If you endorse the idea that at least some cognitive processes are environmentally embedded, you can still hold on to the idea that real cognition goes on in the brain. These brain processes might have been designed to fulfill their cognitive functions only in conjunction with help from the environment, but that does not mean that these processes take place anywhere else than the brain. Cognition may be dependent for its efficacy on things outside the brain, but it is still something that goes on in the brain and not outside it. As we have seen, to say that a cognitive process is environmentally driven does not entail that the process is environmentally constituted. To suppose that it does it to confuse causation and constitution (Adams and Aizawa 2001, 2010; Rupert 2004).
Because of this, the thesis of the embedded mind occupies a rather curious position in recent debate. While it is an interesting thesis in its own right, it is not as radical or-from the point of view of unseating the Cartesian picture of cognition-interesting as the thesis of the extended mind. Therefore, in recent debate, the thesis actually tends to be deployed largely by those who acknowledge the force of the arguments for the extended mind but want to limit their consequences (Adams and Aizawa 2001, 2010; Rupert 2004). In other words, the thesis of the embedded mind has tended to be used as a sort of neo-Cartesian fallback position for those who acknowledge that that are various ways in which the complexity of internal cognitive operations can be reduced by reliance on and use of appropriate structures in the environment but who nonetheless want to maintain that real cognition occurs only in the brain. We shall look in more detail at the role played by the embedded mind in the next chapter.
5 The Mind Enacted
Suppose you are a blind person holding a bottle (O'Regan and Noe 2001). You have the feeling of holding a bottle. But what tactile sensations do you actually have? Without slight rubbing of the skin, tactile information is considerably reduced, and information about temperature will soon disappear through the adaptation of receptors, and so on. Nonetheless, despite the poverty of sensory stimulation, you have the feeling of having a bottle in your hand. According to the traditional approach, the brain supplements, augments, and embellishes the impoverished information contained in sensory stimulation with what are, in effect, various inferences or "guesses" about the sort of thing most likely to be responsible for this stimulation. The result is the construction of an internal haptic (i.e., tactile) representation of the bottle.
However, according to Mackay (1967), there is an alternative explanation: information is present in the environment over and above that contained in sensory stimulation, and this information is sufficient to specify that you are holding a bottle.13 More precisely, your brain is tuned to certain potentialities. For example, it is tuned to the fact that if you were to slide your hand very slightly along the bottle's surface, a change would come about in the incoming sensory signals that is typical of the change associated with the smooth, cool surface of glass. Furthermore, your brain is tuned to the fact that if you were to slide your hand upward far enough, the size of what you are encompassing with your hand would diminish (because you are moving to the bottle's neck). Your sense of holding a bottle is made up of these anticipations of how your experience would change if you were to perform certain types of action. In this, Mackay was drawing (explicitly) on an account of phenomenological presence developed by Edmund Husserl (1913/1982).
According to Mackay, again following Husserl, seeing a bottle is, at least in one respect, analogous to touching it. You have the impression of seeing a bottle if your brain has extracted knowledge concerning a certain web of contingencies. For example, you have knowledge of the fact that if you move your eyes upward toward the neck of the bottle, the sensory stimulation will change in a way typical of what happens when a narrower region of the bottle comes into foveal vision. You have knowledge of the fact that if you move your eyes downward, the sensory stimulation will change in a way typical of what happens when the bottle's label is fixated by foveal vision, and so on.
Mackay's discussion provides an important early illustration of what has become known as the enactive approach to perception, an approach that has received significant recent theoretical development by O'Regan and Noe (2001, 2002), Noe (2004), and Thompson (2007). I shall refer to this as the thesis of the enacted mind (henceforth simply "the enacted mind"). In this section, I want to examine the connection between this thesis and that of the extended mind. In doing so, I am going to focus on Noe's (2004) account. I am not entirely sure the same conclusions can be drawn for all major statements of the enactivist position, but to examine all these statements would be beyond the scope of this chapter.14 Indeed, I suspect there is a way of understanding the enactivist position such that my version of the extended mind-organized around the idea of action on external information-bearing structures-qualifies as a version of this position. Nevertheless, my primary concern here is to distinguish the extended mind, as it was developed in section 3, from at least one deservedly influential statement of the enactivist position: that provided by Noe (2004). In doing so, we help clarify the content of both the mind extended and (this version of) the mind enacted.
Suppose you are looking at a cube. You can't, of course, see the whole of the cube at any given moment; you see only some of its surfaces. Nonetheless, it appears to you that you are looking at a cube.
Noe captures the basic idea of his enactive account in passages such as this:
As you move with respect to the cube, you learn how its aspect changes as you move-that is, you encounter its visual potential. To encounter its visual potential is thus to encounter its actual shape. When you experience an object as cubical merely on the basis of its aspect, you do so because you bring to bear, in this experience, your sensorimotor knowledge of the relation between changes in cube aspects and movement. To experience the figure as a cube, on the basis of how it looks, is to understand how its look changes as you move. (Noe 2004, 77)
Alternatively, consider your visual experience of a tomato. If you look at a tomato you experience it as three-dimensional and round, even though you only see its facing side. Suppose, further, that your view of the tomato is blocked by the pepper pot that stands in front of it. Nevertheless, you experience it as a tomato, and not as a pair of noncontiguous tomato parts. The tomato is phenomenologically present to you, despite the apparent limitations of the visual scene. Traditional accounts would explain this in terms of the construction of a visual representation of the tomato-your brain's guess concerning what is causing your visual impressions. Noe, however, demurs:
Our perceptual sense of the tomato's wholeness-of its volume and backside, and so forth-consists in our implicit understanding (our expectation) that the movements of our body to the left or right, say, will bring further bits of the tomato into view. Our relation to the unseen bits of the tomato is mediated by patterns of sensorimotor contingency. Similar points can be made across the board for occlusion phenomena. (Ibid., 63)
Abstracting from the details, the general idea seems clear. Visually perceiving the world is made up of two things:
1. Expectations about how our experience of an object will change in the event our moving, or the object of our vision moving relative to us (or some other object moving with respect to that object-for example, in front of it). Noe calls this sensorimotor knowledge or knowledge of sensorimotor contingencies. When our expectations are correct, this is because we have mastered the relevant sensorimotor contingencies.
2. The ability to act on the world-that is, to probe and explore environmental structures by way of the visual modality.
Prima facie, of course, the thesis of the extended mind and the enacted mind seem to have much in common. To see how much, recall the earlier characterization of the extended mind; in particular, the first three conditions. First:
• The world is an external store of information relevant to processes such as perceiving, remembering, reasoning ... experiencing.
The enacted mind seems to make use of this claim in much the same way as the extended mind. The role traditionally assigned to visual representations can be taken over, at least in part, by the fact that the visual world is a stable store of information that can be explored at will by the visual modality. The sense of phenomenological presence implicated in our visual experience of a tomato-our sense that in addition to the aspect it presents to us it has other systematically related aspects-is underwritten by the fact that the tomato is a continuous, structured, and stable store of information, one to whose parts or aspects the visual subject is able to direct its attention at will. (In the same way, of course, the bottle is a stable store of haptically obtainable information that can be explored at will by the subject.) Second:
• At least some mental processes are hybrid-they straddle both internal and external operations.
Again, this also seems to be a claim endorsed by the enacted mind. A representationalist account will explain seeing in terms of the production within the subject of an internal visual representation. Visually perceiving, therefore, begins where sensation-the distribution of light intensity over the retina-ends; and it consists in the internal processes responsible for the production of the visual representation. The enactivist approach, on the other hand, thinks that at least some of the role traditionally assigned to visual representations can be taken over by the probing and exploration of visually accessible structures by way of visual modality. Clearly what is going on in the brain is going to be crucially important in this process. But, if the enactivist account is correct, it would be a mistake to suppose that it exhausts the process of visually perceiving the world. To the extent that visual representations are involved, they provide us, at most, with the gist of the visual situation; and the details have to be filled in by suitable probing and exploratory action." If so, then the enacted mind seems to be committed to the hybrid conception of visual perception. Finally:
• The external operations take the form of action: manipulation, exploitation, and transformation of environmental structures-ones that carry information relevant to the accomplishing of a given task.
Probing and exploration of visual structures in the environment do, of course, seem to be forms of action in this sense. If the visual task in question is, for example, producing (i.e., enacting) experiences that reflect the structure, richness, and complexity of the visual environment surrounding the subject, then the enactive account denies that these features need to be reproduced internally-that is, it denies that they need to be reproduced as features of the visual representation. Rather, in its probing, exploratory activities, the perceiving subject exploits the structure, richness, and complexity contained in stable external stores of information, and then uses these to enact experiences that reflect this structural richness and complexity. Thus, the enacted mind also seems to conform to the third condition of our characterization of the extended mind.
On the surface at least, the enacted mind seems to follow closely the characterization I have given of the extended mind. It is, therefore, initially tempting to think of the enacted mind as simply a version of the extended mind. Indeed, I was once thus tempted and did so characterize the enacted mind (Rowlands 2002, 2003). I now suspect that this was premature. Not only are the extended mind and the enacted mind-at least as developed by Noe-different views; it is not even clear that they are compatible views. Thus, it is noticeable that the identified points of similarity between the extended mind and the enacted mind above all turn on the role allotted by the enacted mind to the probing and exploration of the world by the perceiving subject. However, on closer analysis I think we shall find that this role has been grossly overplayed in this sense: it is far from clear that the enacted mind, as developed by Noe, assigns any essential role to this sort of activity. In the remainder of this section, I shall argue that his enacted mind turns on expectations and abilities rather than exploratory activities. And there is no convincing reason for thinking that either of these is extended in the sense required to make the enacted mind a version of the extended mind (Rowlands 2009b).
Recall the two claims that, I have argued, are constitutive of the enacted mind. Visually perceiving the world is made up of two things:
1. Expectations about how our experience of an object will change in the event of our moving or the object of our vision moving (or some other object moving with respect to that object-for example, in front of it). This is sensorimotor knowledge or knowledge of sensorimotor contingencies.
2. The ability to act on the world-that is, to probe and explore environmental structures by way of the visual modality.
Claim (1) concerns sensorimotor knowledge: knowledge that consists in a related set of expectations about how our experience will change given the obtaining of certain environmental contingencies. Claim (2) concerns our ability to act on the world. Adjudicating the claim that the enacted mind yields an extended account of perception, then, amounts to answering this question: is there any reason for supposing that either our expectations or our ability to act (or both) are extended? Is there any reason for thinking that our expectations about how our experience will change in the event of certain contingencies are extended in the way that the extended mind claims (some) mental processes are extended? Is our ability to probe and explore environmental structures extended into, or distributed onto, the world? If the answer t
o both of these questions is "no," then we would have to reject the idea that the enacted mind yields an extended account of perceptual processes. I shall argue that the answer to both questions is, probably, "no." Therefore, appearances notwithstanding, the enacted mind probably does not yield an extended account of perceptual processes.
Claim (1): Sensorimotor Knowledge
There seems to be little reason why expectations about how our experience of an object will change in the event of our moving or the object of our vision moving should be extended. The idea that these sorts of expectations constitute our experience is one that originates in the phenomenological tradition; and they were certainly not introduced there as examples of extended mental processes. So, there is certainly no reason why these expectations must be extended ones. But is there any reason for supposing that they might be?
Noe (2004) claims that these expectations are a form of practical knowledge or knowing how. But, again, there is little reason for thinking that this sort of knowing how is extended. It is common, for example, to think of practical knowledge in procedural terms: that is, in terms of a list of instructions the following of which will, in theory, allow one to accomplish a given task. But there is no reason for thinking that these sorts of instructions are extended; and, typically, that is not the way they have been understood.
If we want to more closely align the mind enacted with the mind extended, one route does suggest itself: a serious injection of Heideggerian phenomenology. If, for example, we were influenced by what we might call the Heidegger-Dreyfus-Wheeler axis, we would want to deny that sensorimotor knowledge can be reduced to procedural knowledge." Our manner of relating to the world, including in this case, the way in which we relate perceptually to the world, is ultimately nonpropositional: propositional modes of relating to the world are always derivative on a more basic way of being-in-the-world. I have a considerable amount of sympathy for this view. If this is what sensorimotor knowledge is, then of course it is extended. It is so for the simple reason that being-in-the-world is extended.