Sunday, June 24, 2018

On Desire 2018. Part 49: Cognitivist Theories of Desires and the Brain

In my last exciting episode I looked at what Timothy Schroeder had to say about the biology of intentional action.

Schroeder, Timothy, (2017), “Empirical Evidence against a Cognitivist Theory of Desire and Action", In Deonna J. & Lauria F. (eds). The Nature of Desire. Oxford University Press.

Now, Schroeder used this as an argument against cognitivist theories of desire. His argument is that cognitivist theories are not consistent with biology.

By cognitivist theories, Shroeder is referring to theories that reduce desires to believes or judgments. These include theories that say, for example, "Agent desires that P" is to be understood as "Agent believes that P is good" or "Agent judges that P ought to be the case."

He provided evidence that, in the brain, intentional action has two main inputs.

One input is the cognitive part of the brain (the unimodal perceptual cortex and the multimodal association cortex). This is the part that we may associate with beliefs and judgments.

Another input comes along pathways that Schroeder says is "not yet interpreted in cognitive or non-cognitive terms". However, he identifies it as "the reward (and punishment) system."

Then, Shroeder looks at three ways to try to make sense of a cognitivist theory of desire.

Option 1: A pathway directly from the cognitive portions of the brain to intentional action.

This exists. The standard course of action is that the cognitive parts of the brain queue up actions, but they are all inhibited. Input from the second pathway selects among the queued up actions which will go through. So, it is possible for the cognitive portion of the brain to queue up an action that goes through without any input from this second system. It just goes straight through, without "obtaining permission" from the second system.

However, Schroeder argues that the types of cases we know about where this happens is Tourette syndrome - the involuntary tics and utterances that those with this system feel compelled to do. Significantly, people with Tourette syndrome do not take these actions to be theirs - they are not "from me". Schroeder also reports, "This same sort of overriding activation, when induced by direct electrical stimulation of the brain, likewise induces movements from which experimental subjects feel alienated."

(I would like to note, as a theory of personal identity, I have played with the theory that what "I am" is a particular set of desires. To say that I am responsible for an action - to say that an action is mine - it must have its source in my desires. If it does not come from my desires, then it is not mine. Schroeder's claims here would be consistent with that thesis. This second system "choosing" among the queued up actions which to let through and turn into actual action is what makes the actin mine. It is what makes "me" the cause of the action. However, I have not worked with this thesis enough to actually endorse it.)

There is a second direct route that need not involve the second (reward/punishment) system. It takes a detour through the motor basal ganglia. Schroeder identifies this as the region of habit formation. I think that a good way to summarize Schroeder's description is to think of the motor basal ganglia as a place where the input of dopamine from the reward/punishment system creates channels of low resistance for certain actions. When queued, these actions "pass through" with little resistance. So, if one has a habit of, say, turning left at a particular intersection, the "turning left" habit may pass through the motor basil ganglia even though, on this one occasion, one actually wanted to turn right. Those bad habits of, for example, biting one's nails are found here.

However, habits are not judgments. Habits, in fact, often go against our better judgments. In this way, we can have good habits and bad habits. So, equating habits with beliefs or judgments that something is good or ought to be the case is problematic.

Option 2: Beliefs or judgments about what is good or ought to be the case are formed in the reward/judgment pathway.

We need not interpret the functioning of the reward/punishment pathway as desires as distinct from beliefs. It may be used to form beliefs of a particular kind - of the kind that motivates action.

Schroeder provides three objections to this interpretation.

First, Schroeder states that such a person must interpret damage to the reward/punishment system of the type that prevents action (extreme Parkinson's disease) as damage to the ability to form beliefs/judgments about what one ought to do. Yet, as Parkinson's disease gets increasingly severe, sufferers do not report increasing difficulty in judging things as good or as something that ought to be done.

I do not see how Schroeder makes a good case here. To make a parallel case with desires, one would have to argue either that Parkinson's disease has an effect on what patients desire. If the effect of Parkinson's disease on desires is the same as that Parkinson's disease would hypothetically have on judgments of goodness or oughtness, then Schroeder hasn't come up with anything that distinguishes one from the other.

So, I don't see Schroeder's argument here.

Second, the functioning of the reward/punishment system is isolated from memory and consciousness.

Apparently, there are no direct connections from the reward/punishment system to the parts of the brain associated with memory or consciousness.

Once one begins to look specifically at the reward system, one sees an absence of projections from this system to regions of the brain that seem involved either in consciousness or in episodic memory, at least, organized in a manner that would support being conscious of or remembering specific judgments of what one has most reason to do, all things considered.

Only the parts of the brain typically associated with traditional beliefs and judgments have these types of connections. I find this quite interesting. It appears to be consistent with the thesis that we do not have very good direct knowledge of our desires - that some of them are unconscious, and that people can be wrong about what it is they desire. We are clearly able to form beliefs about our desires, but we derive those beliefs (like all beliefs) from observing our own behavior and monitoring our body (recognizing symptoms of fear or longing). Like all beliefs, our beliefs about our own desires can be mistaken. Like the rest of the world in general, our desires will influence our action independent of our beliefs in just the same way that the shape of the earth is independent of our beliefs. But the reason we think we have, and the reason we actually have, for doing something may not agree.

Anyway, this draws a genuine distinction between beliefs and judgments about what is good or what one has a reason to do from desires in that unconscious beliefs and judgments are problematic. A person who acts because he judges something to be good is relying on a mental state - a judgment - that has connections to consciousness and memory that desires, apparently, do not have.

Third, pleasure must be "causally upstream" of judgments about reasons, or we cannot judge that we have a reason to do something on the basis that it will be pleasurable. In contrast, pleasure is "causally downstream" of desire. It is in virtue of the fact that one desires something that one gets pleasure from obtaining it. It is not in virtue of the fact that one judges it to be good that one gets pleasure from obtaining it. This represents another distinction between desire and judgment.

So, to me, at least, two of these objections to relating activity of the reward/punishment system to beliefs or judgments about what is good or ought to be the case show that there are problems with this option.

Option 3: The reward/punishment is a component of, rather than the whole story behind, judgments about what is good or ought to be the case.

This option answers the problems about connections to memory and consciousness (since there is a part of the judgment located in the parts of the brain associated with beliefs and perceptions with its strong connections to memory and consciousness). However, it does not answer the objection of the direction of causation. It would still be the case that pleasure must be causally prior to the judgment that a reason for doing something is that it is pleasurable. One must first judge that one has a reason to do it (that one desires it, in the cognitivist sense of desire) before it can be pleasurable.

More importantly, the reward/punishment system can be activated along pathways that have nothing to do with those parts having to do with beliefs and judgments. It can be activated through sensory input directly, as when something tastes good, or one is pleased by the beauty of a sunset or a person. If desire requires both a reward/punishment component and a belief/judgment component, then we cannot prefer the taste of butterscotch to chocolate or prefer Beethoven to Bach. Or, at least, these preferences are not desires.


So, using evidence of brain structure, we can see that there are problems with the thesis that a desire can be understood in terms of a belief that or a judgment that something is good or ought to be the case. This creates a problem for cognitivist theories of desire. But, can a neo-Humean theory of desire do better?

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