Dan Ariely’s nonfiction book Predictably Irrational provides an exciting perspective on the field of behavioural economics. Ariely presents his own theories and research on various aspects of human behaviour. He explains the fundamental differences between traditional economics and behavioural economics in a way that is easy to understand. Traditional economics assumes that people are rational, whereas behavioural economics stresses that they are irrational. Ariely’s primary focus in the work is this debate between rationality and irrationality.
The entire book is written in the first person using an informal tone. The casual tone can be justified as the book is aimed at the general public, as opposed to other researchers and academics. However, given the scientific nature of the information he is presenting, the informal tone also causes his findings to lack assertiveness. Keeping in theme with the informal tone, Ariely uses many anecdotes to convey his findings in a way that is relevant to, and can be understood by, the reader. The anecdotes help the reader grasp the concepts with greater ease, but the addition of personal stories further detracts from the assertiveness of his research. At the risk of losing some readers, it would have been preferred for Ariely to use a more formal approach to match the serious content of his work. Clearly, Ariely aimed to reach a broader range of readers who would not normally study behavioural economics.
The book is geared mainly at an American audience. The research is conducted in the United States except for one experiment done abroad. The beer tasting experiment in chapter 15 is done in both the US and Hong Kong, and the results are different for each location. In both countries, individuals are influenced by other people’s choices when deciding what to order, but in the United States people prefer uniqueness, whereas they wish to conform in Hong Kong (314-316). This discrepancy shows that Ariely’s results cannot be deemed universal until they have been tested in different countries. In chapter four, when discussing social and market norms, Ariely states that even though giving money is much more rational, social norms dictate the exchange of gifts to be more appropriate (96-98). However, in certain societies, particularly in Asia, money is preferred as a gift, showing that the findings are once again specific to an American society and perspective.
Ariely’s experiments are tainted by sampling bias; some segments of the population are overrepresented while other segments are absent entirely. The majority of his experiments are conducted at well-known American universities such as MIT and Harvard. It can be easily argued that students at such institutions are not accurate representatives of the general public. The elderly, the working class, adults older than 30, and those with less or no education are just some of the groups that have been excluded. In one experiment, Ariely further restricts the individuals surveyed to heterosexual males: “Wanted: Male research participants, heterosexual…for this study, we decided to seek out only men. In terms of sex, their wiring is a lot simpler than women” (121). By limiting the key experiment for chapter six to such a specific group, he makes the chapter irrelevant to half of his audience in terms of their own behaviour. Knowledge of men’s behaviour is useful for women, but it reveals nothing about women’s own behaviour when they themselves are aroused. Another important question that arises from his decision to sample only heterosexual males is why not homosexual males? Ariely also conducts some of his experiments in malls, but this again fails to provide an accurate representation of the general population (253). The typical customer varies greatly from mall to mall. If Ariely did his survey on a Tuesday morning at a higher-end mall, he would be encountering very different people than he would on a Saturday afternoon at an outlet mall. The type of mall or time of day play a key role in determining the sample group, but neither of these details is ever specified. Therefore, it cannot be proven that these results apply to the masses because they are only proven for the specific segments of the population tested.