What's social proof?

The first time I came across the term, “social proof” was in Robert Cialdini’s book ”Influence: The Psychology of Persuasion” from the mid-80’s. Cialdini wrote… the principle of social proof says the greater the number of people who find any idea correct, the more the idea will be correct. Social proof is a phenomenon where people follow and copy the actions of others in order to display accepted or correct behaviour, based on the idea of normative social influence. Here are some current examples of social proof, customer testimonials, online reviews, social media shares, celebrity endorsements, and case studies. I think we all use the actions of others to decide on proper behaviour for ourselves, especially when we view those others as similar to ourselves.