Over the past few years, we have discreetly approached colleagues faced with a choice between job offers, and asked them to estimate the probability that they will choose one job over another. The average confidence in the predicted choice was a modest 66%, but only 1 of the 24 respondents chose the option to which he or she initially assigned a lower probability, yielding an overall accuracy rate of 96%.
—Dale Griffin and Amos Tversky1
When I first read the words above—on August 1st, 2003, at around 3 o’clock in the afternoon—it changed the way I thought. I realized that once I could guess what my answer would be—once I could assign a higher probability to deciding one way than other—then I had, in all probability, already decided. We change our minds less often than we think. And most of the time we become able to guess what our answer will be within half a second of hearing the question.
How swiftly that unnoticed moment passes, when we can’t yet guess what our answer will be; the tiny window of opportunity for intelligence to act. In questions of choice, as in questions of fact.
The principle of the bottom line is that only the actual causes of your beliefs determine your effectiveness as a rationalist. Once your belief is fixed, no amount of argument will alter the truth-value; once your decision is fixed, no amount of argument will alter the consequences.
You might think that you could arrive at a belief, or a decision, by non-rational means, and then try to justify it, and if you found you couldn’t justify it, reject it.
But we change our minds less often—much less often—than we think.
I’m sure that you can think of at least one occasion in your life when you’ve changed your mind. We all can. How about all the occasions in your life when you didn’t change your mind? Are they as available, in your heuristic estimate of your competence?
Between hindsight bias, fake causality, positive bias, anchoring/priming, et cetera, et cetera, and above all the dreaded confirmation bias, once an idea gets into your head, it’s probably going to stay there.
1Dale Griffin and Amos Tversky, “The Weighing of Evidence and the Determinants of Confidence,” Cognitive Psychology 24, no. 3 (1992): 411–435.
An interesting article gwern thanks.
It provides a rationale in support of my statement that teenagers are often overconfident in their decision making ability. The article argues that teenagers reward perception is higher and hence the risk seems reasonable compared to the "high" reward; that is one form of overconfidence.
Certainly is interesting to see that adults aren't affected by having a peer present during the experiment, whereas teenagers are more likely to engage in risk taking, perhaps better called - reward seeking - when their peer is watching during the experiment.
But I posted that to say exactly the opposite.
When deciding whether to take a risk, the risk and reward are the two most important factors. It's easy to criticize someone for failing to accurately judge the risk: you simply collect highly accurate statistics on the risk, and compare with what the person says when you ask. But as the article says, when we do this, the teenagers are not discounting risks, but exaggerating them.
So that... (read more)