I'll have what they're having

By Hilary VizelIllustration of a crowd lining up for two food stands

It's lunchtime and you're faced with two food trucks, one of which has a long line of hungry customers in front of it. You might think, “Wow, whatever they’re selling, it must be good!” Or maybe the service is just really slow? Rest assured your assumption of deliciousness is totally normal. While following a herd might sound like an unappealing admission to some, the phenomenon psychologists call Social Proof is an evolutionary adaptive mental shortcut that in this case helps us distinguish "good" food from food we might regret. Studies have shown it can also be a useful method to encourage people to engage in helpful behaviours. One 2008 study found that Social Proof was an effective method to convince hotel guests to reuse their towels. Guests were 35% more likely to reuse their towels when they were told it would help the environment, but 50% more likely to get with the program when told the majority of other guests were also doing it. In other words, we tend to assume the behaviours of others are correct. Which calls to mind another behaviour that can be influenced by Social Proof: jaywalking. We’re far more inclined to start crossing the street when someone ahead of us has already begun their illegal sprint — because our brains are taking a shortcut, just like us.

Use this knowledge It’s probably a bad idea to make a major purchase decision—such as buying a new house or condo—simply because that's what the majority of people like you are doing. But once you’ve settled on a decision that feels right for you, the actions of others could offer a good guideline to follow. Case in point: Most people tend to get pre-approved for a mortgage before they house-hunt. That’s because it’s also a good idea.

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