This principle was first explored by social psychologist Sherif in 1935, and later developed by Asch in 1956. Social proof is the idea that we are intrinsically driven to conform and so will often be influenced to copy others’ decisions and actions, especially when we are hesitating or feel as though we don’t have enough information of our own. We tend to assume that surrounding people possess more knowledge of any given situation and that the actions of others therefore reflect correct behaviour.

This social proof principle is driven by our natural desire to behave “correctly” under most circumstances: we are social and tribal beings, and what others think, say or do is important to us and can be a powerful motivator. This principle also relies on a sense of ‘safety in numbers’, meaning if we are all doing the same thing then we feel we are protected and validated in some way. For example, we’re more likely to work late if others in our team are doing the same, put a tip in a jar if it already contains money, or eat in a restaurant if it’s busy. We assume that if others are behaving a certain way then it must be for a reason: the restaurant is good, the service deserves tipping, the work needs to be finished, etc.

Social proof also applies to marketing and sales. For example, online marketing strategies such as displaying validation logos, subscriber count, social shares or testimonials on a website are all based on the social proof principle. The amount of followers, views, likes, subscribers or past satisfied customers that a user sees positively affects how they will perceive the website. It’s for this reason that we consult TripAdvisor for hotels and restaurants, Consumer Reports before making purchases, Kayak for flight choices, Yelp for eating out, and so on. We want to check and validate our decisions before we make them to ensure we are adhering to the same behaviour as our peers and put a lot of stock in what their testimonials and actions tell us.