Introduction

The consistency principle is the idea that we like to stay consistent with our previous declarations. We are four times more likely to stop a thief if we've previously told someone that we would do something. Robert Chaldini, the author of Influence, describes an experiment that showcases the power of the consistency principle. It was conducted with two groups of people who were asked to contribute to a cancer charity. One week before the donation was requested, the people in one of the groups had been given a cancer-aware badge to wear for a week. When the researchers subsequently asked for a donation, this group donated much more than the control group. The effect is visible in all sorts of human behavior.