Thinking, Fast and Slow: Part 1, Chapter 4 Summary & Analysis

Kahneman next introduces how we form associations and stories. He presents two words: “Bananas” and “Vomit.” He then points out that seeing those two words together causes our minds to experience some disgust, recall unpleasant memories, and form sketchy scenarios that may cause us to have temporary aversions to bananas. These associations occur quickly and effortlessly, as our System 1 attempts to make as much sense as possible of the two words.

The brain is constantly building associations of ideas, with each idea linked to a vast network of other ideas. Causes are linked to effects (virus to cold); things to properties (lime to green); and things to categories (banana to fruit). The mind does not go through a sequence of ideas one at a time, but instead one idea activates many others.

In the 1980s, psychologists discovered that exposure to a word causes immediate and measurable changes in a person’s ability to retrieve related words. For example, if you have recently seen or heard the word EAT, you will be more likely to complete the word fragment SO_P as SOUP. But if you have recently seen or heard the word WASH, you will be more likely to complete it as SOAP. This tendency is called priming, because the idea of EAT primes the idea of SOUP, and WASH primes SOAP. And EAT primes not only the word SOUP, but also a multitude of food-related ideas.

Priming is not merely restricted to concepts and words. In an experiment conducted with students from NYU, one group of students had to unscramble sentences that contained words associated with the elderly, while another group had more neutral words. After unscrambling the sentences, each student had to walk down a hall to get to the next experiment. The students who had words that evoked the elderly walked significantly more slowly down the hall than the others. Thus, people can be primed for a behavior.

This link also worked in reverse. In another study with university students, students were asked to walk around a room for five minutes at a very slow pace. After this experience, the participants were much quicker to recognize words related to old age than other students who were made to walk at a normal pace.

Gestures can also unconsciously influence our thoughts. People who are made to smile by holding a pencil between their lips find things funnier than those who are made to frown—even though they don’t realize that they are being made to do so. People who are told to shake their heads while listening to a message are less likely to accept that message than people who are told to nod their heads while listening to the same thing.

Studies of priming effects sometimes threaten our self-image as conscious and autonomous. A study of voting patterns in 2000 showed that support for propositions that increased school funding gained far more support when the polling station was in a school than when it was at a nearby location. This difference surprisingly outweighed the difference in voting between parents and other voters.

Students who are primed for money in an experiment (even unconsciously) are more independent and selfish. They are less willing to help another student who pretends to be confused about a task. When an experimenter dropped a bunch of pencils on the floor, money-primed people will pick up fewer pencils.

Kahneman writes that people often react to this information in disbelief. He tries to quell fears by saying that the effects of the primes are “robust but not necessarily large”—that among 100 voters, only a few uncertain people will vote differently on a school issue if their precinct is in a school. But the results are not made up, and they are true about everyone.

Kahneman concludes with an experiment conducted in an office kitchen. The office asked for people to pay for the tea or coffee that they consumed by putting money into an “honesty box” with suggested prices posted. Above the price listing was a decorative poster. Each week, they poster would shift between a flowery pattern and a set of eyes. The weeks in which there were eyes above the prices, people contributed almost three times as much money. System 1’s processing, therefore, often affects us without our even being aware of it.