Anyone familiar with Costco knows about the wide variety of free food samples that shoppers can score when pushing their oversized carts around one of the wholesale clubs. But as you’ve probably guessed, these samples aren’t just about providing free piecemeal lunches to customers.

The Atlantic’s Joe Pinsker recently took a look at the psychological underpinnings of free samples at Costco. Of course, since the company is so tight-lipped about a lot of the things it does, he had to rely on research and observations of others.

Here are some of the highlights from the Atlantic piece…

1. The samples may engender a sense of obligation in consumers
When you snack on that free sample of summer sausage, or wash it down with some free coconut water, there’s a chance you might feel like you should buy something.

“Reciprocity is a very, very strong instinct,” explains Dan Ariely, a behavioral economist at Duke University. “If somebody does something for you… you really feel a rather surprisingly strong obligation to do something back for them.”

2. The samples might lead you to buy something similar
Maybe that coconut water didn’t knock your socks off, but it might have caused you think about another beverage that you do want, but that you hadn’t planned on buying.

“What samples do is they give you a particular desire for something,” says Ariely. “If I gave you a tiny bit of chocolate, all of a sudden it would remind you about the exact taste of chocolate and would increase your craving.”

Sure, the company that is sponsoring the samples might care that you buy something else, but for Costco, an impulse purchase is a definite win.

3. You’re more likely to buy when others are around
Pinsker cites a 2011 study from the UK on sampling that found that “Samplers with a heightened awareness of the presence of others at the sampling station may feel a level of social ‘pressure’ to make a post-sample purchase.”

So if a sample table just had free cookie bites sitting there without anyone to smile and hand them to you, shoppers wouldn’t feel as pressured to buy.

4. It’s ultimately about creating a distinct “Costco” atmosphere
Sure, other stores give out samples, but few are as linked to the notion of sampling as Costco. It’s something fun that brings shoppers back and makes the shopping experience more pleasant. Much like many Costco shoppers look forward to bargain (but reasonably tasty) hot dogs and pizza during their visit, they have come to associate the samples with a day at the ‘Co.

You should definitely check out Pinsker’s entire article for more insights on sampling and its role in Costco’s identity.

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