Yale School of Management

Center for Customer Insights

Advancing the frontiers of consumer understanding

A Shopper in Motion

First purchases dramatically increase the likelihood of second purchases. Recent research out of YCCI reveals the psychological underpinnings of this effect, offering marketers a new avenue for influencing consumer decisions.

November 20, 2014

In England, in 1687, Isaac Newton released the first edition of his magnum opus, Mathematical Principles of Natural Philosophy. Among other foundational concepts, he outlined three laws of motion—now a kind of catechism in ninth-grade science classes across the United States.

The first law succinctly describes the idea of inertia. In loose translation from Latin: “an object at rest remains at rest, and an object in motion remains in motion, unless acted on by an outside force.”

More than three centuries later, Ravi Dhar of YCCI, Joel Huber of Duke University, and Uzma Khan of Stanford University have revealed an interesting analog in the world of consumer decision-making. “Shopping momentum arises from the idea that shopping has an inertial quality,” they wrote in a 2007 article for the Journal of Marketing Research. Consumers who made a first purchase, who set shopping in motion, were much more likely to make a second, unrelated purchase.

Dhar and his colleagues demonstrated shopping momentum through two related experiments. In the first, one group of participants was given the opportunity to purchase an educational CD, followed by the opportunity to purchase a keychain. A control group was only given the choice to purchase a keychain. Among those who first bought the CD, more than 75 percent went on to buy the keychain, while only about 45 percent of the control group bought the keychain.

Extending these findings, a follow-up experiment, which used a pen instead of a CD, inserted a third scenario: the pen would be offered for free followed by an opportunity to buy the keychain. In this case, Dhar and his colleagues found that 77 percent of participants bought the keychain after having an option to first buy the pen. In contrast, those who were given the pen for free, or who were only presented with a keychain and no choice to buy a pen, bought the keychain about 50 percent of the time.

The results were clear: the option to make a first purchase boosted the likelihood of a second purchase. The results also shed light on a possible cause, of particular interest to marketers who are trying to encourage purchases. “Although the term ‘momentum’ suggests a physical mechanism,” write Dhar and his coauthors, “the theory behind shopping momentum derives from psychology.” Specifically, a first purchase shifts consumer mindsets from one that is deliberative—careful to weigh pros and cons—to one that is implementation-based—focused on goal-oriented action. These mindsets, in turn, affect behavior.

With a series of two more experiments, Dhar and his colleagues demonstrated two important insights. First, making a purchase does, in fact, shift one’s mindset from a deliberative to an implementation orientation. Second, by simply priming people with an implementation mindset—no actual purchase necessary—they are likelier to make a purchase than if they are in a deliberative mindset. In the end, shopper momentum is contingent on whether consumers are in a more deliberative or implementation-oriented mindset, and making purchases can nudge them toward the former.

Interestingly, the momentum metaphor applies in ways beyond simply the likelihood of a second purchase. For instance, the stronger the impulse to make a first purchase—the more attractive the item is—the greater the propensity to make a second purchase. In other words, more desire to make a first purchase results in a stronger push and, therefore, greater momentum. Additionally, “friction” generated by diversionary actions or stimuli can serve to weaken shopping momentum. For example, when items must be paid for using two separate sources, this can induce friction. Shopping momentum is also likely to dissipate over time, which, the authors note, suggests that “a disruption in shopping momentum leads to lost sales rather than deferral over time.”

Newton’s groundbreaking laws, today, are thoroughly understood. They account for the outlandish possibility of landing small probes on comets that are streaking through vast open space. But the three laws of marketing demand more exploration: What first sets shoppers in motion? What determines their degree of inertia? And what variables generate friction?

And one can’t help but wonder: is there such a thing as the perpetual shopping machine?