Too Long; Didn't Read
<strong><em>Nir’s Note:</em></strong><em> This guest post is an excerpt from the new book </em><a href="https://amzn.to/1ozH5fL" target="_blank"><em>Invisible Influence: The Hidden Factors that Shape Behavior</em></a><em>, written by my friend and Wharton School professor, </em><a href="http://jonahberger.com/" target="_blank"><em>Jonah Berger</em></a><em>.</em>