Ariely explains, "My goal, by the end of this book, is to help you fundamentally rethink what makes you and the people around you tick.

I hope to lead you there by presenting a wide range of scientific experiments, findings, and anecdotes that are in many cases quite amusing.

Ariely discusses many modes of thinking and situations that may skew the traditional rational choice theory.

A value can be as easily (arbitrarily) assigned as by having a fancy ad with "equally" precious items and a high price tag in a window of a store on Fifth Avenue.

In other words, decisions about future LCD television purchases become coherent after an initial price has been established in the consumer's mind.

Using the concepts of anchor price and arbitrary coherence, Ariely challenges the theory of supply and demand.

Furthermore, supply and demand are dependent on each other (manufacturer's suggested retail prices affect consumers' willingness to pay).

The outcome was consistent: when faced with multiple choices, the free option was commonly chosen.

We forgo some of our time when we wait in line for free popcorn or to enter a museum on a free-entrance day.

Ariely recommends the consideration of the net benefits of the choices we make regarding both preference and money.

In chapters 4 and 5, Ariely speaks in great detail of the differences between social norms—which include friendly requests with instant payback not being required—and market norms—which account for wages, prices, rents, cost benefits, and repayment being essential.

In fact there are some situations in which work output is negatively affected by payment of small amounts of money.

"[6] In chapter 6, Ariely collaborated with close friend George Loewenstein, a professor of economics and psychology at Carnegie Mellon University, to test the influence of arousal on decision making in high-emotion situations.

Ariely and Loewenstein chose to test the effects of sexual arousal on decision-making in college-aged men at University of California, Berkeley.

Using the data, Ariely argues that other high-emotion situations such as anger, frustration, and hunger have the potential to trigger similar effects on decision-making.

To avoid the endowment effect, Ariely suggests that we create a barrier between ourselves and the material things we are tempted by daily.

In the "blind test" the majority preferred the altered brew, but when they were told in advance that it was vinegar-laced, they chose the original Budweiser.

Another group of students was made aware of the vinegar content immediately after tasting both kinds of drinks.

The author describes an experiment in which an objective math exam was administered to two groups of Asian-American women.

In chapter 10, Ariely started out with a medical procedure called internal mammary artery ligation for chest pain.

This chapter ended with a complex and moral question as to whether or not the placebo effect in medicine should be studied more closely or even eliminated systematically.

In November 2021, it was reported that NBC had put a pilot commitment to a television series adaptation of the book titled The Irrational with Arika Lisanne Mittman as executive producer.

[9] In December 2022, it was announced that NBC had given the production a series order with Jesse L. Martin set to star.

[12] In a New York Times review, David Berreby said "Predictably Irrational is a far more revolutionary book than its unthreatening manner lets on.

It's a concise summary of why today's social science increasingly treats the markets-know-best model as a fairy tale.