What the research shows:
A mix of ages helps teams perform better, but only when the team enjoys thinking hard. In teams that don’t, the same mix makes performance worse.
Source: Kearney, E., Gebert, D., & Voelpel, S. C. (2009). When and how diversity benefits teams: The importance of team members’ need for cognition. Academy of Management Journal, 52(3), 581–598.
Researchers in Germany studied 83 teams from eight organisations in software, pharmaceuticals, insurance, telecoms, food and energy. These were real teams doing knowledge work, such as developing products, marketing and customer service, and working closely together several times a week. The researchers wanted to know why age diversity helps some teams and hurts others.
Their answer lay in a trait called “need for cognition”: how much people enjoy effortful thinking. Team members rated themselves on statements such as “I really enjoy a task that involves coming up with new solutions to problems.”
Key findings
- Thinking teams gain from the mix. When a team’s average need for cognition was high, age diversity was linked to better performance.
- Quick-answer teams lose from it. When the need for cognition was low, age diversity was linked to worse performance. The mix isn’t neutral: it cuts both ways.
- Two things explain the difference. Diverse teams that enjoyed thinking worked through each other’s knowledge more, and felt a stronger shared identity as a team.
- It’s not just about age. A mix of educational backgrounds followed the same pattern.
“Diversity gives a team more to think with. It only helps if the team wants to think.”
What we found interesting
The need for cognition isn’t fixed. The authors describe it as stable but open to development, and they note that people who don’t naturally enjoy deliberating will still do it when they have a good reason. They suggest leaders can help by making the work personally meaningful, spelling out why different views matter, building psychological safety, and holding the team accountable for how it reaches decisions, not just what it decides.
That turns a personality finding into a practical one. You can’t always choose who’s on your team, but you can build habits that make slowing down and thinking together the norm. Those are the conditions in which experience across generations pays off.
Summary prepared by our research team with AI support.
