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%.
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.
I would say that the study by Griffin and Tversky is incomplete. The way I see it, we have an inner "scale" of the validity of evidence and decide based on that. As was pointed out in one of the previous posts, we should bet on an event 100% of the time if the event is more likely than the alternatives. Something similar is happening here, where if we are more than 50% sure that job A is better than job B, we should pick job A. Given that the participants were 66% sure, this would mean that there is a low a priori probability for them to change their minds. If we assume a normal distribution for the "scale" of evidence in our brains, we get to the fact that there is indeed a very small chance of the participants changing their minds, obviously being a 2 sigma event.
If my hypothesis is correct, in a new study in which the participants are a priori 50% sure about the job they want to choose, they should change their minds more than the 4% in this example, much more actually. Given that we do have a mechanism in our minds that makes us stick to our decisions, especially in cases when we are around 50% sure, which stops us from changing our minds constantly and behaving erratically, I would hypothesize that the participants wouldn't change their minds 50% of the time, but it would probably be in the region of 40% - 50%. I would also expect that when the participants are 80% or 90% sure a priori, that they would still change their minds in maybe 1% or 2% of the cases because we are usually more sure of our answers than we should be.
All in all, I think that it is perfectly rational that if you are 66% sure about something you make that decision in 90% to 99% of the cases. Being 80% sure about something should not mean that you should choose the alternative in 20% of the cases.
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.