Daniel Kahneman's Thinking Fast and Slow is my third favorite business book, third only behind the two oracles Built to Last and Good to Great. Though it's clearly a psychology book, to me it's the machine code behind what drives all sales and marketing. I feel so strongly about its value that I think I'm going to start a series on the book's practical applications in business, but I figured I'd start with this one fun nugget from the book, as it's a good example of what I mean. (Moreover, it makes for a fun headline.)

In a nutshell, the book is about how we have an intuitive part of our brain that is always effortlessly running in the background, and a conscious, thinking part of our brain that is painful for us to use. Obviously we much prefer to use "system 1." This lazy but hyperefficient part influences our conscious thinking to a far greater extent and much more often than you would expect and makes us really bad at being intuitive statisticians.

The book covers a study that demonstrates this. Each study that the book discusses whittles away at your confidence in the control you have over your decisions until you start to doubt who's really at the wheel. This particular study will probably trip you out a small bit, but that's nothing compared to others. Imagine that 1,000 times in a row.

The Setup: The "Tom W." Question

In this Harvard study, participants were asked to answer the "Tom W." question. This is a question engineered by the author, and it is intentionally designed to show how poor we are at being intuitive statisticians.

It goes like this:

Tom W. is a graduate student at the main university in your state. Please rank the following nine fields of graduate specialization in order of the likelihood that Tom W. is now a student in each of these fields. Use 1 for the most likely and 9 for the least likely. Business administration

Computer science

Engineering

Humanities and education

Law

Medicine

Library science

Physical and life sciences

Social science and social work

Even with no information provided, humans do a pretty good job at this. They can readily pull up the "base rate" and know about how many people are in each field of specialization and simply rank them accordingly, knowing nothing about Tom W.

Next they tell you a little about Tom W.:

Tom W. is of high intelligence, although lacking in true creativity. He has a need for order and clarity, and for neat and tidy systems in which every detail finds its appropriate place. His writing is rather dull and mechanical, occasionally enlivened by somewhat corny puns and by flashes of imagination of the sci-fi type. He has a strong drive for competence. He seems to feel little sympathy for other people and does not enjoy interacting with others. Self-centered, he nonetheless has a deep moral sense.

(You'll get more out of this if you go through the motions and rank them right now.)

Once you know things about Tom, the intuitive part of your brain easily compares them with the schema for each of the fields and suggests them to your "system 2." Remember, using system 2 is painful, so anytime we get a chance to accept and pass on through the suggestion from system 1, we tend to do it, because it's painless. As long as it makes sense enough, we allow it. However, this is not the correct way to approach the answer, because you have to take into account the size of each department. For example, Tom W. sounds like a geek for sure, but if the CS department is 1/100th the size of the humanities department, Tom W. is still more likely to be a humanities major -- but that's just not how our brains work. Make sense? Now admit it: You ranked CS and engineering at the top, didn't you?

Frowning Activates the Critical Part of Your Brain

So, in this study that Daniel covers, half the students conducted the study while frowning, and half while puffing out their cheeks. The former is something known by psychologists to better engage and ready "system 2," or the more conscious, analytical and painful-to-use part of the brain. This means that frowning "reduces overconfidence and reliance on intuition." Puffing out your cheeks, on the other hand, is an emotionally neutral action and does not affect the results of the other group.

So Why Does Frowning Make You Better at Answering the Tom W. Question?

The students who were frowning and thus activating their system 2 more heavily are much more likely to not immediately pass through the suggestion from system 1 (which is effectively just matching up stereotypes, something very easy for us to do). These students were more likely to say, "Hold your horses, lazy part, let's consider the sizes of the respective departments." As a result, these students came up with more statistically reasonable rankings.

If you are fascinated by this, read the book. If you want to know more about this particular study, it's related to the Representativeness_heuristic.