Mixing these norms yields unexpected negative results and often damages social relationships.Ĭhapters 5 and 6 explore how financial transactions and high emotional states disrupt social norms, or the unwritten rules that help people navigate social interactions. Chapter 4 addresses something even more troublesome: when people insert money into situations that operate under social rather than market norms the former norms require no money, while the latter do.

Gravitating toward a FREE! item is not inherently bad, but it becomes irrational when someone picks the FREE! item over a better option (such as choosing a free $10 gift certificate over a $20 gift certificate for seven dollars). Despite humans’ desire for rational decisions, many decisions stem from first impressions and gut feelings.Ĭhapter 3 highlights that humans also get an emotional charge from FREE! items, regardless of whether those items are products or money. He then expands on the idea of relativity, presenting evidence for how humans anchor to initial prices and use these first impressions as a reference point for future similar items this influences subsequent decisions (an idea known as arbitrary coherence). Ariely suggests people’s decisions are based on an item’s comparability-or relativity-to other items.

Chapters 1 and 2 explore one such influence: the human lack of an internal meter for evaluating an item’s worth. The latter edition is the basis for this guide.įollowing the Introduction, Ariely details the various influences on human behavior as well as how a person might overcome some of these forces. While the book was originally written in 2008, Ariely published a revised and expanded edition in 2010 with Harper Perennial.

Predictably irrational by dan ariely