Predictably Irrational: The Hidden Forces That Shape our Decisions

In Chapters 5 and 6, Ariely examines economic factors that disrupt social norms. Humans are social creatures and rely heavily on interactions with others. To help themselves navigate these interactions and prevent chaos, people establish social norms or unwritten rules. Because these social norms are key to a functioning society, it is important to understand what might override them—such as financial transactions. Take the scenario of the free cookies versus that of the cookies at a cost: When asked to buy a coworker’s cookies, a person will likely take many more cookies than they would if those cookies were offered for free; in the latter situation, the “consumer” considers social norms since other coworkers might also want cookies. This contrasts with the first scenario, in which the element of financial transaction invoked market norms that overpowered social norms. These two examples are not mere thought exercises, as is demonstrated by Ariely’s experiments. Individuals act more selfishly and individualistically when money is introduced into social transactions. There really is power in a free cookie. The cookie scenario not only highlights human irrationality, but it shows how human behavior diverges from traditional economic theory expectations.

Chapter 6 focuses on how high emotional states disrupt not only social norms but rational thought. In an emotionally piqued state, people often act differently than they would in a neutral state. More importantly, they fail to predict how they would react in different emotional states. Ariely thus underscores that “we must be wary of situations in which our Mr. Hyde may take over” (130).

While humans are predictably irrational, Ariely strongly believes that they are not helpless. In fact, knowledge is power. By understanding what factors—like financial transactions and piqued emotional states—disrupt social norms and cause irrationality, people can improve their behavior and policies. One policy example relates to sexual education for teenagers. Ariely notes that “many parents and teenagers, while in a cold, rational, Dr. Jekyll state, tend to believe that the mere promise of abstinence—commonly known as ‘Just say no’ is sufficient protection” (130) against pregnancy and sexually transmitted diseases. As Ariely suggests in this section, however, it will be more difficult to avoid sexual activities under the highly emotional state of arousal. He suggests sex education should focus less on abstinence and more on safe sex and strategies to deal with emotions like arousal. By changing sex education so that it considers human irrationality, people may better prevent teenage pregnancies and sexually transmitted diseases.