How peer pressure does—and doesn't—influence our choices

It's a familiar scenario: You go out to eat with a friend, and he or she orders a Caesar salad. Your friend's choice inspires you to order a salad, too—only you decide to mix things up a little and choose a chef salad instead. This scenario sits at the center of a persistent marketing puzzle: Why are we more likely to copy our friends in certain domains but not in others?

A new theory developed by Kelly Haws, Anne Marie and Thomas B. Walker, Jr. Professor of Marketing at Vanderbilt's Owen Graduate School of Management, suggests that we tend to want to match characteristics that can be measured or ranked, such as size or price, but feel free to diverge on characteristics that can't, such as flavor or shape. And we do this to avoid awkwardness.

Her findings are reported in Mindful Matching: Ordinal Versus Nominal Attributes, forthcoming in the Journal of Marketing Research. Peggy Liu of the University of Pittsburgh and Brent McFerran of Simon Fraser University are her co-authors.

Through a series of 11 experiments, Haws and her co-authors explored a number of nuances that govern these decisions. While they focused on food choices, they also looked at a charitable giving scenario to test whether their findings could extend to other decision-making areas.

Broadly speaking, we tend to match the choices of others along ordinal lines. These might be numerical characteristics such as size, price or number, but also more abstract value-based concepts like perceived healthiness, prestige or authenticity.

"Ordinal attributes are ones in which we believe in general that there's a particular order in which they exist," Haws said. "So in other words, one is better than another."

We don't feel the same pressure to match what the researchers call nominal attributes. These are subjective characteristics, such as shape or flavor. In the donation experiment, the charity choice served as the nominal attribute, and the researchers found that the same effect—matching donation amounts but not charities—persisted.

Furthermore, Haws and her co-authors found that we didn't just match our friends' ordinal choices, we matched store employees," too. When asked, participants who chose to match said their decisions were driven by a desire to avoid social discomfort.

"If you order a double-scoop ice cream cone, I might infer that this is an occasion where we're celebrating or indulging together," Haws said. "But if you order a single-scoop ice cream cone, I might instead think, "Well we're enjoying a treat, but we don't want to get too carried away with it." And this is an instance where I'm going to go for the smaller size. It's much less comfortable to mismatch on that dimension."

Haws said her findings can help managers make better decisions about how to shape consumers' choices through store signage, employee interactions and other cues. "There are many different areas in which these underlying nominal-versus-ordinal attributes could play out in the marketplace."