What convinced more people to go out and vote for Obama? The same method that could motivate more people to buy from you. This approach is already pushing further:

o Hikers to stay on marked trails.

o Hotel guests to use fewer towels.

o Homeowners to reduce their energy use.

(By giving you these examples, I was using the method to convince you that this must be a useful method if used in so many different ways.)

To encourage more supporters to vote, the Obama campaign enlisted behavioral scientists to craft the message that has been repeated in recent days: “Record turnout expected.” They were evoking social proof.

Simply put, social proof means that we are more likely to do what we think many others are doing. Robert Cialdini described this effect in his popular book Influence, as have others, including Cass Sunstein (now working for Obama) and Richard Thaler in Nudge.

Similarly, an anti-literacy campaign is hugely successful because it evoked our collective pride, with the slogan “Don’t mess with Texas.”

The effect of social proof is stronger in times of uncertainty (people are not sure and/or the situation is ambiguous) or similarity (we are more likely to follow people who are like us).

You see variations of the social proof effect every day:

o You choose the busy restaurant instead of the almost empty one. You are drawn to the crowded booths at the trade show or expo.

o After a murder/suicide is reported, head-on car crashes and plane crashes increase immediately.

o Fewer people now smoke in the US as it has fallen out of fashion except in groups where it is still popular.

o For twenty minutes a day, children who were afraid of dogs stood in front of a child who was happily playing with a dog. After just four days, 67 percent of them climbed into a playpen with a dog and played with it. Shy children can also get help.

o If several people around you are overweight, you are more likely to gain weight.

o Bartenders sometimes “salt” the tip jar for customers to deposit money.

o Desperate women invade the men’s room at a Springsteen concert, after the former bravely enter.

Brain imaging shows that when we think we’re out of step with our peers, the part of our brain that registers pain goes into overdrive, according to Cialdini. The herd instinct is strong.

Social proof occurs when a business attracts more customers because, unlike the competition, it displays testimonials. When you see this woman looking at one of the two men, you assume that he is more attractive and important than the other man, simply because of where she is looking. Therefore, display your product near popular and non-competing products or other items.

Using social proof in small, even inexpensive, ways has a huge effect. For example, Positive Energy, a company where Cialdini is the scientific director, is invoking social proof to get homeowners to voluntarily reduce their energy use. Along with their utility bill, they receive a note praising them, “with a row of smiling faces (You used 58 percent less electricity than your neighbors this month!) your neighbors in the last 12 months, and it cost you $741 extra).”

That led to a 2 percent drop in energy use when tested in Sacramento with just 35,000 homes. That’s the same as taking 700 households off the grid. Next social proof move? Reduction of water consumption.

Such neighbor or peer pressure, especially with consequences, is a powerful way to change behavior, as stickK is demonstrating.

Conformity, competition, even embarrassment, are powerful motivators when social proof is evoked. For example, a public campaign in one county in Oregon to get homeowners to weatherize their homes cheaply received little response. However, when churches, citizen groups, and Girl Scouts were recruited for a door-to-door campaign, 85% of the county signed up. (Which credible partners can you engage in a social proof-based campaign?)

If you want people to buy from you, provide as many ways and places (website, brochure, conversation, articles, etc.) for them to hear or read about the ones you already have. This type of social proof evokes the power of Previous Previous. The more your customers or customer situations or reasons to buy remind potential buyers of themselves and their situation, the stronger their impulse to buy will be. Girl Scout parents, for example, were struck by the need to weatherize their homes.

What worthy organization can benefit from aligning with your business to evoke social proof?

That was how the Toluma firefighters obtained a much-needed but expensive piece of equipment, a deluge gun, without asking their cash-strapped city council for a dime. Business was slow throughout his city. Firefighters got nowhere when they asked business owners experiencing a weak economy for donations.

They approached the manager of the locally owned MyPizzaria to request a donation. Instead, the manager devised a way to evoke social proof to attract donations, to their mutual benefit. “Here’s what I can do. We can pick a Wednesday, say four weeks from now to declare as ‘Saving a local life’. Eat firefighting pizza at MyPizzeria.” It is usually a quiet night. I make $500 or so. That day after we sell $500 worth, every dollar after that I’ll split 80/20 with you – your cause gets 80% So if you inspire enough people to buy a pizza that day, you can raise more money than you you just asked me.”

The firefighters loved the challenge, and had downtime to participate. They had banners, signs and ads printed for free by the local copy shop with a bright red “donated by” line of credit. They asked local supermarkets and gas stations to display them. After the first posters appeared, the local association of real estate agents decided that this was a popular campaign (social proof). As avid and savvy web users, real estate agents stepped up to help spread the word.

Within hours of travel, two fire trucks, draped with banners, had firefighters and realtors waving on the busy street. Then the growing army of volunteers visited complex offices, even those with signs that read “No Soliciting.” (Who’s going to kick out the firefighters?) Now, more patrons visited apartment complexes, video rental stores and schools. They put flyers and signs everywhere. Once people learned about their community’s cause, handing out flyers was like giving out candy. The local radio station, newspaper and various bloggers covered the unfolding story.

When Wednesday finally arrived, the place was packed with lively people. Some were served at tables in the parking lot, thus attracting passers-by (another sign of social proof at work). They made enough money to get the deluge gun. The most important thing was fun and a victory for all participants. Done right, social proof-based campaigns can attract a crowd so more gets done with less work from everyone.

Additionally, this partnership based on social proof allows all parties to use their best talents and resources. Acting together for mutual benefit creates deeper and more diverse friendships. Because they experienced the leverage power of partnership, participants are more likely to want to work together again.