Unreal Nature

January 23, 2010

Disjoint

Filed under: Uncategorized — unrealnature @ 7:39 am

… It is tempting to think that phenomenally conscious states are more or less a subset of access conscious states, but if Raftopoulos is right, it is closer to the truth to hold that the two classes are disjoint. 

This is a long post that probably nobody will read, but, dammit, it’s interesting. Nutritious, good for you even if it takes a lot of chewing. It’s from a review of the book, Cognition and Perception: How Do Psychology and Neural Science Inform Philosophy? by Athanassios Raftopoulos; reviewed by Jack Lyons in Notre Dame Philosophical Reviews. This first section is a long quote from the Raftopoulos’s book itself — quoted by reviewer Lyons, and now quoted by me: 

Visual information is first processed in an entirely bottom-up manner during a feedforward sweep phase; a local recurrent phase follows, during which there is top-down and lateral processing, but it is local in the sense that it is all still preattentive (with a qualification to be noted shortly): the task demands and thus the goals, expectations, and other “cognitive” states of the organism don’t affect processing until later. The results of the local recurrent phase are short-lived, unstable representations, delivered in parallel, and carrying information at roughly the level of Marr’s 2½D sketch; motion, color, orientation, and spatial locations and relations of surfaces and objects are represented. These representations constitute phenomenal consciousness, in Block’s (1995) sense. Objects (better: “proto-objects”, to emphasize the low level of processing) are segregated and individuated at this early stage on the basis of spatiotemporal features, although object identification occurs later and requires attention and application of concepts and cognitive resources. 

“Perception” gives way to late vision when object-centered attention comes into play with the global recurrent phase. This phase involves input from frontal and prefrontal areas, as well as mnemonic circuits. Object-centered attention selects among the unstable representations produced by early vision, choosing some for further processing. The result is the familiar product of late vision: a stable percept with conceptual content, including information about object identity, function, etc. (One of several possible terminological confusions is apparent here: a “percept” is not the product of “perception” but rather of “late vision”, which is a species of “cognition”.) Access consciousness, or report awareness, also requires attention and therefore occurs during late vision; it lags behind phenomenal consciousness and has a very different content, in part because of the additional processing involved. 

There are two kinds of attentional effects in vision: the object-centered attention just discussed biases processing in accordance with task demands, subject’s expectations, etc., but this top down influence does not occur until after the local recurrent phase is finished. Spatial attention, on the other hand, does have early effects on processing, but it only affects the amount of processing devoted to a given region of space; it does not bias the interpretation of the contents of that region. Object-centered attention biases processing by modulating the activity of the same neural regions involved in early vision, boosting the activation of certain feature detectors in accordance with cognitive input, but not until after a bottom-up processing phase is completed. Spatial attention primes all the feature detectors for a given spatial location, irrespective of which features they detect. It thus alters where we look, but not what we see when we look there. Neither, therefore, is it a threat to the theory-neutrality, or cognitive encapsulation, of perception. Object-centered attention affects content but is post-perceptual, and spatial attention is preperceptual and doesn’t affect content. 

All of the rest is by the book’s reviewer: 

… Perceptual learning — which makes its first appearance surprisingly late in the book — is no argument for theory-ladenness, because it involves only data driven changes. Perceptual states are not independent of one’s experiences, but they are independent of one’s theory; we can check on each other’s perceptions without adopting their theory. Such a conclusion has obvious consequences for the anti-realist philosophy of science that is supposed to follow from the theory-ladenness of perception. This is taken up in Chapter 8. Scientists with different theoretical commitments can still perceive the same thing, even though what they observe will be different. Raftopoulos holds that true belief is not sufficient for realism; we must also show that our nonconceptual perceptions carve up the world appropriately. He argues (via inference to the best explanation) that even this stronger requirement for realism can be satisfied. 

… Raftopoulos claims that the content of perception is nonconceptual precisely because it is causally insulated from cognitive/conceptual capacities. 

… It is fairly common to define nonconceptual content in something like the following terms: a contentful state has nonconceptual content just in case one could be in that state without having any concepts. Taking this statement at face value and conjoining Raftopoulos’s theory of vision, the existence of nonconceptual content follows immediately, for the outputs of early vision are representational states, and one’s perceptual processes do not rely in any way on conceptual processes or representations. This is an important move, although many readers surely will not like it. One response that will tempt the conceptualist at this point is to deny that these states have genuine content. Raftopoulos argues at length that they do, however, and the conceptualist will have to take these arguments seriously. 

… it is not at all clear that perceptual states, as Raftopoulos construes them, would be much use to the typical internalist epistemologist after all. Internalism is often founded on the conviction that one should have conscious access to the grounds on which one’s beliefs are held (Alston 1988), or that the justifying states be such that the agent can tell, by mere introspection, whether or not she is in them (Chisholm 1989). It is not clear that the phenomenally conscious states delivered through early vision will play either of these roles. Recall that, for Raftopoulos, phenomenal consciousness arises from the local recurrent processing phase, which offers up fleeting and unstable representations with nonconceptual content. Because of the instability, these states are difficult to isolate in experience (p. 169). Furthermore, once we turn our attention to our phenomenal experience, the global recurrent phase kicks in and alters that experience, not only because attention brings conceptual content into play, but also because attention triggers further processing of the proto-objects of phenomenal consciousness. Raftopoulos is insistent that conceptual content is not just nonconceptual content with the addition of concepts. One of several important products of Part I is his theory about the relation between phenomenal consciousness and access consciousness. It is tempting to think that phenomenally conscious states are more or less a subset of access conscious states, but if Raftopoulos is right, it is closer to the truth to hold that the two classes are disjoint. 

This might matter a lot for the theory-neutrality debate. Even if a scientist’s observational beliefs are produced by the phenomenal states, science is a public endeavor, and the final appeal of the scientist’s arguments for a given theory have to rest either on reports of observations (late-visual perceptual beliefs about physical objects) or reports about experiences. Both are late-visual and thus nonencapsulated. 

If anybody made it through my quotes and wants more (fifty points and two gold stars for you!), read the whole review. I did. Three times (and I have a lot of questions for Mr. Raftopoulos). [ link

I’m pondering how much of a difference it would make if one moves the out-there to in-here transition from the beginning of cognition to somewhere later in cognition. Also am wondering when memory happens (memory would seem to me to require some sort of conceptualization) — and if one can have cognition without memory (of some kind, however brief). 

-Julie 

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1 Comment

  1. This is very interesting but it is dependent on a jargon with which I am not completely familiar (to say the least!). Learning the jargon would, in the very process, alter how I read the theory. However, what is presented is very much higher than the nitty gritty of neurobiology, i.e. electrons gone wild, with which I am more familiar.

    At random, what are the “proto-objects of phenomenal consciousness?” Whatever they are at the bottom they are collections of neurons in a particular pattern. Until we sort that out, some of this is entirely speculative.

    Comment by Dr. C. — January 23, 2010 @ 8:43 pm


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