When University of Alabama Associate Professor of International Business Stan Westjohn set out to study email marketing, he wasn’t interested in just open rates or click-throughs. He wanted to know something deeper: how persuasion works across borders. As an international business scholar, he spends much of his time thinking about cultural distance and the subtle differences in values, norms, and perceptions that separate one country’s consumers from another’s.
His latest research, “The effect of distance on persuasion in international e-mail marketing campaigns,” was published in International Business Review, and explores what happens when those differences collide with classic marketing psychology.
Westjohn and co-author Peter Magnusson, formerly a professor of international marketing at Culverhouse who is now a professor of marketing at the University of Texas Rio Grande Valley, turned to Robert Cialdini’s well-known principles of influence, the kind of persuasion tactics that make people buy faster, sign up quicker, or trust more deeply. Among them are scarcity, authority, and consensus, also known as social proof. Westjohn wanted to know if these tactics work the same way when a company in one culture markets directly to customers in another.
“Think about an Irish company selling to Americans,” Westjohn explained. “Culturally, those two aren’t that far apart. But if you shift the seller to India, suddenly the distance feels larger. The question is whether persuasion works differently when that gap widens.”
To test this, his team focused on email marketing. They could see not only whether a message was opened but also whether the recipient clicked, replied, or followed through. In carefully designed experiments, participants received emails promoting a fictitious résumé service. Some emails leaned on social proof, telling readers that “others like you are already using this.” Others leaned on authority, citing experts or credentials. The senders varied: sometimes the company was framed as Irish, other times Indian.
The results revealed a striking pattern. When the cultural distance was small, like Irish to American, consensus was the stronger persuasion tool. Americans felt close enough to identify with Irish peers, so the “everyone’s doing it” appeal resonated. But when the cultural distance was larger, like Indian to American, authority proved more persuasive. Faced with less familiarity, Americans put more weight on credentials and expertise than on the behavior of “people like them.”
Westjohn calls this a matter of uncertainty. In uncertain situations, people look for cues to reduce doubt. If they see similarity, they follow the crowd. If they feel difference, they lean on expertise. “It’s not that one is better than the other,” he said. “It’s that the effectiveness depends on the distance between the seller and the buyer.”
In a real-world field experiment, emails went out to potential applicants worldwide, using the same persuasion strategies. The results matched the earlier studies that students from culturally closer countries responded better to consensus, while those from more distant countries responded more to authority.
For Westjohn, that replication in a live campaign was the most exciting part. “You run these studies for years, and then you get to see it work in the real world. It’s like, ‘wow, this actually plays out,’” he said.
The research highlights a practical lesson for marketers in an era when cross-border selling is commonplace. Companies can’t assume persuasion is universal. A message that clicks in Canada may fall flat in China unless it’s reframed with the right appeal. Even something as seemingly simple as an email subject line can succeed or fail depending on whether it leans on similarity or expertise.
“It’s about knowing when to point to the crowd, and when to point to the expert.” Westjohn said.