We all want a little excitement from our relationships, but exactly how much is influenced by how long we see that relationship lasting, according to new research from Duke University's Fuqua School of Business.

Professor Jordan Etkin found the variety of activities we choose within committed relationships depends on whether we consider more of the relationship as being in the future or in the past.

"When you perceive a long time ahead, you choose more variety in your shared activities, but as you perceive less time ahead you begin to trim the variety out and focus on similar things," Etkin said. "That finding is consistent for romantic partners, long-term friends, any close and ongoing relationship characterized by frequent interaction."

The research, "Choosing Variety for Joint Consumption," is newly published in the Journal of Marketing Research.

Moved by an argument with her husband over what to do one weekend — he wanted to try a mix of new things, she wanted to go out to eat — Etkin conducted five studies to test how much variety people want in the activities they share with a relationship partner.

"Research into couples can be difficult, but this was easier to test because I was studying one person choosing activities for joint consumption," she said.

In one experiment, Etkin asked 192 people in committed romantic relationships to choose activities they'd like to do with their partners over the following week. Participants who had been primed to perceive more time ahead in their relationships — they were asked beforehand to describe how that time could be considered long or short — chose more varied activities.

A similar experiment using 200 people in long-term friendships produced the same results, and found participants rated excitement as more important when they perceived more time ahead in the relationship.

Further experiments manipulating participants' sense of excitement in activities, or the length of time their relationships had lasted, further supported the earlier findings.

"The conclusion is that if you haven't been together for long then you want more variety, but if you see less time ahead then you want less variety," Etkin said.

Previous work in psychology has shown that as we grow older and perceive less time in our future than in the past, what makes us happy changes from excitement to calm. Etkin's research shows that also applies to relationships.

"The type of positive emotions that people desire from a relationship differ depending on that future time perspective," she said. "When you have all this time in front of you, you want things to feel exciting and that's what drives your choices. But as a relationship moves through time and your future time shrinks, you desire excitement to a lesser extent.

"It's not to say that when you've been together a long time that no variety is good," Etkin said. "Sharing novel experiences contributes to self-growth and the development of a relationship. But on an average weekend you might be happier settling for doing one new thing with a longstanding relationship partner instead of three new things. But if that one thing is eating out, you might eat out at different restaurants. It's not the exact same thing, but it's a narrowing down."

The results deepen understanding of what drives consumer decision-making, Etkin said. Since relationship time perspective influences how much variety we prefer, it could also play a role on the effectiveness of ads that highlight the variety of experiences consumers could have together.

"Consumers often use recommendation systems, such as TripAdvisor or Yelp, to help guide joint consumption decisions," Etkin said. "These findings suggest that consumers' relationship time perspective could inform what these systems should recommend."

Prior research has shown that much consumer choice is influenced by social relationships. This work illuminates one way in which this happens. Plus, Etkin said this understanding can even help people within a relationship manage it better.

"Satisfaction across relationships plays a huge role in our happiness as individuals," she said. "This research shows thinking about where we are in our relationship and getting on the same page about how much time we have ahead of us can help us align our variety preferences — and then not fight about it."