Joe Pinsker examines “The Psychology Behind Costco’s Free Samples” for The Atlantic. The whole piece is worth a read but this excerpt answers the question:
It’s true that free samples help consumers learn more about products, and that they make retail environments more appealing. But samples are operating on a more subconscious level as well. “Reciprocity is a very, very strong instinct,” says Dan Ariely, a behavioral economist at Duke University. “If somebody does something for you”—such as giving you a quarter of a ravioli on a piece of wax paper—“you really feel a rather surprisingly strong obligation to do something back for them.”
Ariely adds that free samples can make forgotten cravings become more salient. “What samples do is they give you a particular desire for something,” he says. “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.”
I’m clearly an outlier, in that I’m a regular Costco customer (a store opened half a mile from my home about a year ago and I do the bulk of my food shopping there) but hardly ever take samples. I know I’m not going to buy frozen pizza rolls, so don’t bother tasting them. Most of the time, when the sampled food would otherwise appeal to me, it’s a product I’ve already purchased in the past and see no need to taste it again in the store. And I’m perfectly willing not to buy something that I’ve sampled if I don’t like it or don’t think it’s a good value.
