Laura Occasionally Blogs

I read a lot of pop psychology nonfiction which means I get reintroduced to a lot of intro psych concepts. For example, the representativeness heuristic is the idea that people tend to overestimate the likelihood that a situation will reflect a "representative" or stereotypical example, like when we see an argumentative toddler and predict she'll become a lawyer.

Consider the "Linda problem" (Amos Tversky and Daniel Kahneman):

Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations.

Which is more probable?

1. Linda is a bank teller.

2. Linda is a bank teller and is active in the feminist movement.

Logically, A is always more probable than A && B, and our desire to give answer #2 (A && B) could be an example of the representativeness bias (we want Linda to adhere to our representation of an activist rather than a bank teller), but, while I have no problem believing in the bias, I think this result could also be explained by our expectations of conversation, particularly if the test was given orally.

Linguistics sidebar!! This is my favorite thing to explain in linguistics, so you may have heard this from me already.

Paul Grice's "cooperativeness principle" proposes that people are generally cooperative in conversation and assume the same from their partner--that is, they're trying to contribute to a meaningful exchange of information, not just saying random shit for no reason. His conversational maxims, paraphrased by me:

1. Quantity: Give the right amount of information; don't say too much or too little. This is context-dependent, but, for example, giving cross-streets when a new acquaintance asks where you're from is wrong, as is saying "Oregon" when your cab driver asks where you want to go.

2. Quality: Be truthful

3. Relevance: Be relevant. Don't give unrelated information. This one can produce some creativity, as people will automatically do mental gymnastics to interpret anything you say as being relevant: hence the fun of turns of phrase such as "Is the pope Catholic?"

4. Manner: Be as orderly and straightforward as possible; "avoid unnecessary prolixity" (I remember that last phrase from Grice because it violates itself.)

So if your friend were to describe Linda and ask you to guess her job and interests, you would assume that all the information he gave mattered to your answer, per the maxim of relevance. People normally don't give you unnecessary information. So that could have thrown off participants.

Further, when people answered the question, they were also trying to be cooperative, and to give as complete of an answer as they could, per the maxim of quantity. Only stating "A" when you have equal reason to believe "A && B" violates every conversational instinct.