In our previous episode, we looked at Peter Railton’s theory of belief.
(Bel p) A belief that p is a compound state consisting in (1) a degree of confidence or trust in a representation, p, that (2) gives rise to and regulates a degree of expectation that things are or will be as p portrays them, and (3) this degree of confidence or trust is disposed to strengthen or weaken in response to the extent to which this expectation that p is met or violated in subsequent experience.
Railton, Peter, (2017), “Learning as an Inherent Dynamic of Belief and Desire,” In Deonna J. & Lauria F. (eds). The Nature of Desire. Oxford University Press.
He then makes a similar claim about desire.
(Des p) A desire that p is a compound state consisting in (1) a degree of positive affect or favoring toward a representation, p, that (2) gives rise to and regulates a degree of expectation that p will be satisfying or beneficial and a corresponding degree of motivation to bring about or sustain p, and (3) this degree of positive affect or favoring is in turn disposed to strengthen or weaken in response to the extent to which this expectation that p is met, exceeded, or disappointed in subsequent experience.
His overall goal is to claim that beliefs and desires are species of the genus “sentiment”.
(Sent p) A compound mental state in which (1) a degree of sentiment toward a representation, p, that (2) gives rise to and regulates a degree of action-guiding and potentially motivating expectation with respect to p, and (3) this degree of sentiment is in turn disposed to be modulated by whether, and to what extent or in what direction, this expectation with respect to p is met or violated.
With this in mind, let’s go back to (Des p) - which is short for “Desires p” if you did not catch that - and (Sent p) refers to having a particular sentiment towards P where beliefs and desires are both types of sentiments.
The key component relevant to this discussion is going to be Railton's third component. This identifies what Railton calls "learning". In the case of belief, one's encounter with evidence increases or decreases the strength of one's sentiment that the belief is true - its credence. Railton's claim is that there is a component of desires that is also called "learning" that makes desires like beliefs. This is what he describes in (3) the degree of positive affect or favoring is in turn disposed to strengthen or weaken in response to the extent to which this expection that p is met, exceeded, or disappointed in subsequent experience.
Railton is providing an accurate account of how the reward mechanism works. The reward system actually measures a "deviation from expectation". This is shown in experiments. If, as a result of some action, the results are exactly what the agent expects then there is no reward signal. Everything remains steady at its baseline. However, if the agent obtains an unexpected benefit - a pleasant surprise - there is a reward signal. This reward signal increases the "positive affect" of that which causes the reward.
This is easier to illustrate in the case of unexpected pain or some other averse reaction. As one goes about one's business, one encounters a particular type of plant with white berries, or a mushroom, or an insect with black and yellow stripes. The result is a rash (poison ivy), vomiting (poisonous mushroom), or a bee sting. The effect of this encounter with the environment is not just to cause one to learn to avoid this type of plant as a means of avoiding a rash, or to avoid mushrooms as a means to avoid vomiting, or to avoid bees as a means to avoiding bee stings. One acquires an aversion to running through the bushes and prefers to say in open areas. One acquires an aversion to mushrooms and will not touch a mushrooms - picking the mushrooms out of one's food if one should find them. One acquires a fear of bees and simply wants to be away from them "for its own sake".
Railton describes another type of case - an individual who desires to become a lawyer. Upon becoming a lawyer at a top law firm, she discovers that she does not like it as much as she thought the would. The effect of the persistent disappoint is to cause her desire to become a lawyer at a top law firm to diminish. Her interaction with the state of actually being a lawyer, according to Railton, causes her desire to diminish as she learns the "true value" of being a lawyer.
It is certainly the case that interaction with the environment can change one's desires in this way. However, the question remains whether this counts as "learning" in the relevant sense. More specifically, do these types of changes count as learning the true value of that which one is evaluating. In the next post, I will argue that it does not.
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