"Predictably Irrational" explores how people make decisions and how they are influenced by their emotions, expectations, and environment. Ariely argues that people are not rational agents, but rather predictably irrational, and that our behavior can be influenced by factors like pain, expectation, and the framing of choices.
If you're interested in Dan Ariely's work, you might also want to explore his other books, such as "The Honest Truth About Dishonesty" (2012) and "The (Honest) Truth About Dishonesty: How We Lie to Everyone---Especially Ourselves" (2012).
You're looking for a paper by Dan Ariely, specifically "Predictably Irrational" in PDF format.