Posts Tagged ‘rationality’

Thinking, Fast and Slow

Sunday, January 15th, 2012

Book review: Thinking, Fast and Slow, by Daniel Kahneman.

This book is an excellent introduction to the heuristics and biases literature, but only small parts of it will seem new to those who are familiar with the subject.

While the book mostly focuses on conditions where slow, logical thinking can do better than fast, intuitive thinking, I find it impressive that he was careful to consider the views of those who advocate intuitive thinking, and that he collaborated with a leading advocate of intuition to resolve many of their apparent disagreements (mainly by clarifying when each kind of thinking is likely to work well).

His style shows that he has applied some of the lessons of the research in his field to his own writing, such as by giving clear examples. (”Subjects’ unwillingness to deduce the particular from the general was matched only by their willingness to infer the general from the particular”).

He sounds mildly overconfident (and believes mild overconfidence can be ok), but occasionally provides examples of his own irrationality.

He has good advice for investors (e.g. reduce loss aversion via “broad framing” – think of a single loss as part of a large class of results that are on average profitable), and appropriate disdain for investment advisers. But he goes overboard when he treats the stock market as unpredictable. The stock market has some real regularities that could be exploited. Most investors fail to find them because they see many more regularities than are real, are overconfident about their ability to distinguish the real ones, and because it’s hard to distinguish valuable feedback (which often takes many years to get) from misleading feedback.

I wish I could find equally good book for overuse of logical analysis when I want the speed of intuition (e.g. “analysis paralysis”).

Paranoid Debating

Friday, April 3rd, 2009

At last Sunday’s Overcoming Bias meetup, we tried paranoid debating. We formed groups of mostly 4 people (5 for the first round or two) and competed to produce the most accurate guess to trivia questions with numeric answers, with one person secretly designated to be rewarded for convincing the team to produce the least accurate answer.

It was fun and may have taught us a little about becoming more rational. But in order to be valuable, it should be developed further to become a means of testing rationality. As practiced, it tested some combination of trivia knowledge and rationality. The last round reduced the importance of trivia knowledge by rewarding good confidence intervals instead of a single good answer. I expect there are ways of using confidence intervals that remove the effects of trivia knowledge from the scores.

I’m puzzled about why people preferred the spokesman version to the initial version where the median number was the team’s answer. Designating a spokesman publicly as a non-deceiver provides information about who the deceiver is. In one case, we determined who the deceiver was by two of us telling the spokesman that we were sufficiently ignorant about the subject relative to him that he should decide based only on his knowledge. That gave our team a big advantage that had little relation to our rationality. I expect the median approach can be extended to confidence intervals by taking the median of the lows and the median of the highs, but I’m not fully confident that there are no problems with that.

The use of semi-randomly selected groups meant that scores were weak signals. If we want to evaluate individual rationality, we’d need rather time consuming trials of many permutations of the groups. Paranoid debating is more suited to comparing groups (e.g. a group of people credentialed as the best students from a rationality dojo, or the people most responsible for decisions in a hedge fund).

See more comments at Less Wrong.