Wednesday, February 13, 2013

Thinking Fast and Slow: Daniel Kahneman

Daniel Kahneman's Thinking Fast and Slow was much better than I expected it to be. Not that I wasn't expecting it to be well written or interesting, just that I expected that since Kahneman's results and views have been covered in great depth in a lot of other works I've read, I didn't expect much to be new. Even if you're fairly familiar with Kahneman's results and ideas, the book presents them well, and gives good advice on how to take advantage of your brain's predilections and work around its shortcomings.

Kahneman is well known as the progenitor (with Amos Tversky) of the Heuristics and Biases literature. You will find references to their research and results in lots of popular presentations on how people think, and the various ways in which people are prone to mistaken beliefs and sub-optimal actions. In Thinking Fast and Slow, he presents a unified discussion of this work, along with some solid suggestions for integrating the conclusions into your approach to life so that you can get more of what you want and be happier.

The basic theory is that we have two main approaches to problem solving with divergent benefits. The fast thinking part ("System One") is ready to make snap judgements on any subject at any time. It is fast, but it takes lots of shortcuts, and doesn't even bother to choose an optimal shortcut. Whatever answer first presents itself to this part of our minds is latched onto, because the evolutionary benefit was in having some answer quickly in case our ancestors needed to react immediately. The other approach is slow and deliberate, and involves evaluating lots of alternatives and consciously weighing benefits as well as the appropriateness of each approach to the current problem. The problem with System Two is that it's expensive, and for good evolutionary reasons your instincts always offer a quick and dirty response before there's time to consider more carefully.

Kahneman spends the bulk of the book giving lots of examples of particular, named, classes of mistakes we make ("Availability Heuristic", "Illusion of Validity", "Endowment effect", etc). It's probably useful to be aware of these classes if you want to reason more clearly, but I see the main value of Kahneman's approach to be in making us aware that our snap judgements are suspect. There are good reasons for each bias, which explains why evolution selected for that particular outcome, but whenever you're not in a life-and-death race to escape a lion, it pays to be attentive to your innate biases and consider your options more carefully. Having names for a catalog of short-sighted trade-offs you are likely to have gravitated to makes it easier to see which first guesses to re-think.

The final section of the book follows another perspective, also first identified by Kahneman and Tversky. This is the idea that our "Experiencing Self" and our "Remembering Self" have different evaluations when comparing things we do, which can lead to strange trade-offs when choosing what to do. The author argues that our memories systematically underweight pain we experience and consistently get some things wrong about enjoyable times, leading us to guess incorrectly about what kinds of situations we'd prefer in the future.

Experimental evidence shows that peoples' memories of painful episodes (dentist visits, for example) are dominated by the experience of the final moments of the experience, neglecting how painful earlier parts were. This means that adding 5 minutes of sligtly painful procedures to the end of a very-painful 15 minute procedure actually makes people remember the whole incident as having been less painful. Many people argue that it's clearly wrong to choose 20 minutes of pain over 15 minutes of pain, but this is not obvious to me. The 15 minute session should also carry the burden of all the subsequent time when the patient had to remember the more painful portions more clearly. The 20 minute session may have included more pain while in the chair, but the experiments show that the patients were less upset long afterward, partly because they had less gripping memories subsequently. So, as I see it, it's less of a contradiction than Kahneman believes.

On the other side, our recollections of enjoyable situations are also skewed. We tend to neglect long periods of time spent in pleasurable avocations (Kahneman calls it "duration neglect"), and when asked to choose how to spend our time or money, people often opt for the choice with a more easily recalled high point, regardless of the duration or enjoyability of the entire experience. Kahneman recommends that when planning vacations, or choosing other ways to spend our time, we focus more on the ongoing experience rather than the extremes. He's pretty convinced that we'll get more out of life that way. The counter is that when recalling our lives we'll be subject to just these biases, and regardless of how much joy there was in the small moments, we'll focus on the highs and lows when remembering our story or telling it to other people. It's food for thought in either case.

1 comment:

William H. Stoddard said...

The evidence on remembered pleasure and pain leads to an interesting critique of utilitarianism. Utilitarianism argues that you should maximize the sum of pleasure net of the sum of pain. Usually this is treated as disregarding time effects. But if you do that, you seemingly aren't going to maximize the sum of retrospective evaluations of total past pleasure and total past pain over the course of your life.