For those unfamiliar, social proof is the psychological phenomenon of how people’s behavior can be swayed to conform to the behaviors of the people around them.

It’s the celebrity on the billboard wearing the jacket you now want.

It’s the laugh track on your TV comedy show.

It’s your friends doing your bragging for you to the cutie at happy hour.

And it’s those customer testimonials and customer ratings that you should be gathering and displaying on your online retail website.

Social proof is hard-wired into human psychology, as was demonstrated in the famous “Street Corner Experiment” in 1968. Social psychologist Stanly Milgram demonstrated the principle of social proof with four people on a busy street corner looking to the sky—at nothing at all. A startling 80% of passersby conformed to the same behavior.

Yeah, we’re sheep, basically.

But while this ingrained behavior isn’t exactly voluntary, it IS pretty smart when you think about it: There IS wisdom in the crowds!

Consider the fundraiser where people guess the number…