Cognitive Psychology Of Consciousness Research Paper

There are two prima facie reasons for thinking that the Hard Problem has no solution.

(a) Actual failure. In fact, no one has been able to think of even a highly speculative answer.

(b) Principled failure. The materials we have avail-able seem ill-suited to providing an answer. As Nagel (1974) says, an answer to this question would seem to require an objective account that necessarily leaves out the subjectivity of what it is trying to explain. We don’t even know what would count as such an explanation.

1. Perspectives On The Hard Problem

There are many perspectives on the Hard Problem but I will mention only the four that comport with a naturalistic framework.

(a) Phenomenal realism, the view that consciousness is a substantial property that cannot be philosophically reduced in nonphenomenal terms. According to most contemporary phenomenal realists, consciousness plays a causal role and its nature may be found empirically as the sciences of consciousness advance. Phenomenal realism is compatible with the empirical reduction of consciousness to neurological or computational properties of the brain. (This is the perspective of this research paper.) This view accepts the Hard Problem but aims for an empirical solution to it. (Block 1995, Flanagan 1992, Nagel 1974, Searle 1992; McGinn 1991 argues that an empirical reduction is possible but that we can’t find or understand it.)

(b) Dualistic naturalism. In this catch-all category, I include Chalmers’ (1996) view that standard materialism is false but that there are naturalistic options to dualism such as panpsychism. Nagel (forthcoming) proposes that there is a deeper level of reality that is the naturalistic basis both of consciousness and of neuroscience.

(c) Eliminativism, the view that consciousness as understood above simply does not exist (Dennett 1979, Rey 1997). So there is nothing for the Hard Problem to be about.

(d) Philosophical reductionism. Philosophical reductionists (e.g., Dennett 1991) move closer than eliminativists to common sense by allowing that consciousness exists, but they ‘deflate’ this commitment—again on philosophical grounds—taking it to amount to less than meets the eye (as Dennett might put it). One prominent form of philosophical reductionism in this sense makes a conceptual reductionist claim: that consciousness can be conceptually analyzed in non-phenomenal terms. The main varieties of analyses are functional, representational, and cognitive. Many philosophical reductionists disparage a priori conceptual analysis, but nonetheless hold that we know on purely philosophical grounds (independently of the sciences of consciousness) that consciousness is constituted by the functional, representational, or cognitive.

Here are some examples of philosophical reductionism. Pitcher (1971) and Armstrong (1968) can be interpreted as analyzing consciousness in terms of beliefs. One type of prototypical conscious experience, as of the color blue, is a matter of an inclination (perhaps suppressed) to believe that there is a blue object in plain view. (See Jackson 1977 for a convincing refutation.) A different analysis appeals to higher order thought or higher order perception. These theorists take the concept of a conscious pain to be the concept of a pain that is accompanied by another state that is about that pain. A pain that is not so accompanied is not a conscious state (Armstrong 1968, Carruthers 1992, Lycan 1990, Rosenthal 1997 advocates a higher order thought view as an empirical identity rather than as a conceptual analysis). Another philosophical reductionist view that is compatible with the analyses in terms of beliefs concerns not the states themselves but their contents. Representationism holds that it can be established philosophically that the phenomenal character of experience is its representational content. Many representationists reject conceptual analysis, but still their accounts do not depend on details of the science of mind; if any science is involved, it is evolutionary theory (see Harman 1990, Dretske 1995, Lycan 1996, McDowell 1994, Tye 1995; Shoemaker 1994 mixes phenomenal realism with representationism in an interesting way). Conceptual functionalists say that the concept of consciousness is analyzable functionally (Lewis 1994).

According to these views, there is such a thing as consciousness, but there is no Hard Problem, that is, there are no mysteries concerning the physical basis of consciousness that differ in kind from run of the mill unsolved scientific problems about the physical functional basis of liquidity, inheritance, or computation.

2. How To Begin Solving The Hard Problem

The main element in the approach I shall be suggesting to the Hard Problem is a distinction that is widely appealed to in discussions of Jackson’s (1982) famous ‘Mary’ example. Jackson imagined a neuroscientist of the distant future who is raised in a black and white room and who knows everything scientific there is to know about color and the experience of it. But when she steps outside the room for the first time, she learns what it is like to see red. Jackson argued that since the scientific facts don’t encompass the new fact that Mary learns, dualism is true.

The line of response to Jackson that I think wins the day (and which derives from Loar 1990 1997) involves appeal to the distinction between a property and a concept of that property. (See Churchland 1989, Lycan 1990, van Gulick 1993, Sturgeon 1994, Tye 1999, Perry forthcoming.)

A concept is a thought element in a way of thinking, a kind of representation. If you like, you can take concepts in my sense to be interpreted symbols in a ‘language of thought.’ This usage contrasts with a common philosophical usage in which a concept is something like a meaning. Concepts in my sense are individuated in part by meanings; x and y are instances of the same concept if and only if they are instances of the same representation and have the same meaning.

Someone could believe that this color is useful for painting pots but that red is not, even if this color red. Our experiential concept of red differs from our linguistic concept of red. An experiential concept involves a phenomenal element, a phenomenal way of thinking, for example a mental image that is in some sense of red or an ability to produce such a mental image or at least an ability to recognize red—which arguably, could not be done without some phenomenal mental element.

Importantly, we can have an experiential concept of an experience (which we can call a phenomenal concept, phenomenal concepts being a subclass of experiential concepts) as well as an experiential concept of a color. And the very same mental image may be involved in both concepts. The difference between the phenomenal concept of the experience and the experiential concept of the color lies in the rest of the concept—in particular, the way the phenomenal element functions in the concept. This can be a matter of further concepts explicitly invoked in the concept—the concept of a color in one case and the concept of an experience in the other. One type of experiential concept (of a color or of an experience) involves a demonstrative plus a mental image plus a language-like representation, e.g. ‘that [attention to a mental image] color’ or ‘that [attention to a mental image] experience’ where the bracket notation is supposed to indicate the use of attention to a nondescriptive element, a mental image, in fixing the demonstrative reference. Loar (1990 1997) gives an example involving two concepts in which something like a mental image of a cramp feeling is used to pick out a muscular knot in one concept and in the other concept, the cramp experience itself. The two concepts in my notation would be ‘that [attention to a mental image] cramp’ and ‘that [attention to a mental image] cramp experience.’

In these terms, then, Mary acquired a new concept of a property she was already acquainted with via a different concept. In the room, Mary knew about the subjective experience of red via physical concepts. After she left the room, she acquired a phenomenal concept of the same property. So Mary did not learn a new fact. She learned a new concept of an old fact. She already had a third person understanding of the fact of what it is like to see red. What she gained was a first person understanding of the very same facts. She knew already that corticothalamic oscillation of a certain frequency is what it is like to see red. What she learned is that this [attention to a mental image] is what it is like to see red. So the case provides no argument that there are facts that go beyond the physical facts.

Recall that there is a principled reason why mind– body identity seemed impossible: that a first person subjective property could not be identical to a third person objective property. But the concept–property distinction allows us to see that the subjective–objective distinction in this use of it and the first person– third person distinction are distinctions between kinds of concepts, not kinds of properties. There is no reason why a subjective concept and an objective concept cannot pick out the same property. Thus we can substitute a dualism of concepts for a dualism of properties.

3. The Paradox Of Recent Empirical Findings About Consciousness

The most exciting line of experimental investigation of consciousness in recent years uses the phenomenon of binocular rivalry. If two different stimuli—e.g., horizontal and vertical stripes—are presented to each of one’s eyes, one does not see a blend, but rather alternating horizontal and vertical stripes. Logothetis and his colleagues (Logothetis 1998) trained monkeys to pull different levers for different patterns. They then presented different patterns to the monkeys’ two eyes, and observed that with monkeys, as with people, the monkeys switched back and forth between the two levers even though the sensory input remained the same. Logothetis recorded the firings of various neurons in the monkeys’ visual systems. In the lower visual areas (e.g., V1), 80 percent of the neurons did not shift with the percept. But further along the occipital-temporal pathway, 90 percent shifted with the percept. So it seems that later areas in the occipital-temporal pathway—let’s call it the ‘ventral stream’— are more dominantly part of the neural basis of (visual) consciousness than early areas.

However, what has also become commonplace is activation of the very same ventral stream pathways without awareness. Damage to the inferior parietal and frontal lobes have long been known to cause visual extinction in which subjects appear to lose subjective experience of certain stimuli on one side, viz., when there are stimuli on both sides. Extinction is associated with visual neglect in which subjects do not notice stimuli on one side. For example, neglect patients often do not eat the food on the left side of the plate.

Driver and Vuilleumier (2001) point out that the ventral stream is activated for extinguished stimuli (i.e., which the subject claims not to see). Rees et al. (in press) report studies of a left-sided neglect and extinction patient on face and house stimuli. Stimuli presented just on the left side are clearly seen by the patient, but when there are stimuli on both sides, the subject says he sees only the stimulus on the right. However, the ‘unseen’ stimuli show activation of the ventral pathway that is the same in location and temporal course (though lower in activation) as the seen stimuli. The paradox then is that our amazing success in identifying the neural correlate of visual experience in normal vision has led to the peculiar result that, in masking and neglect, that very neural correlate occurs without, apparently, subjective experience.

What is the missing ingredient, X, which, added to ventral activation, constitutes conscious experience? Kanwisher (forthcoming) and Driver and Vuilleumier (2001) offer pretty much the same proposal as to the nature of X, that the missing ingredient is binding perceptual attributes with a time and a place, a token event.

Whether or not any of these proposals are right, the search for X seems to me the most exciting current direction for consciousness research.

There is a very different approach to the nature of consciousness. Dennett (1994) postulates that consciousness is ‘cerebral celebrity.’ What it is for a representation to be conscious is for it to be widely available in the brain. Dehaene and Naccache (forth-coming) say consciousness is being broadcast in a global neuronal workspace.

The theory that consciousness is ventral stream activation plus e.g., neural synchrony, and the theory that consciousness is broadcasting in the global neuronal workspace, are instances of the two major approaches to consciousness in the philosophical literature: physicalism (though ‘biologism’ would be more appropriate in this context) and functionalism. The difference is that the functionalist says that consciousness is a role, whereas the physicalist says that consciousness is a physical or biological state that implements that role. Although functionalists are free to add restrictions, functionalism in its pure form is independent of implementation. Consciousness is de-fined as global accessibility, and although its human implementation depends on our biochemistry, silicon creatures without our biochemistry could implement the same computational relations. Thus functionalism and physicalism are incompatible doctrines since a nonbiological implementation of the functional organization of consciousness would be regarded as conscious by the functionalist but not by the physicalist. The big question for functionalists is: ‘How do you know that it is broadcasting in the global workspace that makes a representation conscious as opposed to something about the human biological realization of that broadcasting?’

Many of us have had the experience of suddenly noticing a sound (say a jackhammer during an intense conversation), and at the same time realizing that the sound has been going on for some time even though one was not attending to it. If the subject did have a phenomenal state before the sound was noticed, that state was not broadcast in the global neuronal work-space until it was noticed. If this is right, there was a period of phenomenality without broadcasting. Of course, this is anecdotal evidence. But the starting point for work on consciousness is introspection and we would be foolish to ignore it.

In this section, we have seen a distinction between two concepts of consciousness, phenomenality and global accessibility. In the following section, we add a third, reflexivity.

4. Phenomenality And Reflexivity

Rosenthal (1997) defines reflexive consciousness as follows: S is a reflexively conscious state S is accompanied by a thought—arrived at noninferentially and nonobservationally— to the effect that one is in S. He offers this ‘higher order thought’ (HOT) theory as a theory of phenomenal consciousness. It is obvious that phenomenal consciousness without HOT and HOT without phenomenal consciousness are both conceptually possible. For examples, perhaps dogs and infants have phenomenally conscious pains with-out higher order thoughts about them. For the converse case, imagine that by biofeedback and imaging techniques of the distant future, I learn to detect the state in myself of having the Freudian unconscious thought that it would be nice to kill my father and marry my mother. I could come to know—noninferentially and nonobservationally— that I have this Freudian thought even though the thought is not phenomenally conscious. Since there are conceptually possible counterexamples in both directions, the issue is the one discussed above of whether reflexivity and phenomenality come to the same thing in the brain.

If there are no actual counterexamples, the question arises of why. Is it supposed to be a basic law of nature that phenomenality and reflexivity co-occur? That would be a very adventurous claim. But if it is only a fact about us, then there must be a mechanism that explains the correlation, as the fact that both heat and electricity are carried by free electrons explains the correlation of electrical and thermal conductivity. But any mechanism breaks down under extreme conditions, as does the correlation of electrical and thermal conductivity at extremely high temperatures. So the correlation between phenomenality and reflexivity would break down too, showing that reflexivity does not yield the basic scientific nature of phenomenality.

The reader may wonder why Rosenthal includes ’noninferentially and nonobservationally’ in the definition. The answer is: because one could find out that one is depressed by observing one’s own behavior. This would not be conscious depression, but such a thought would be arrived at observationally and inferentially. However, this restriction is ad hoc, motivating the search for definition that is not ad hoc. Here is one: S is a reflexively conscious state S is phenomenally presented in a thought about S. This definition uses the notion of phenomenality, but this is no disadvantage unless one holds that there is no such thing apart from reflexivity itself.

We have seen three concepts of consciousness: phenomenality, reflexivity, and global accessibility. The Hard Problem arises only for phenomenality. The imaging work on consciousness engages phenomenality and accessibility. But many psychological experimental paradigms mainly engage reflexivity.

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