The team picture was typical of LinkedIn: a smiling group, portrayed as best friends who just happened to be a cross-functional launch team. Happy, harmonious and… hopelessly staged. Only days before, I’d watched this same team struggle through a meeting marked by tension and territoriality. And yet I also knew that while this particular team was riven with conflict, a significant minority of teams are genuinely cohesive. This column is about why harmony emerges in some teams and conflict in others, and what the science of human groups tells us about how to manage your own team.

To understand team dynamics, it helps to be a poker player. Look around the meeting room when, for example, the brand lead speaks and notice the tiny tells: the slight eyebrow lift from Medical, the tight smile from Market Access, the Sales director’s arms folded just a little too tightly. It’s all very polite but there isn’t agreement or even constructive disagreement. Decades ago, corporate cultures tolerated raised voices and direct conflict. Today, as recent research has shown, workplace norms have shifted towards relational harmony and emotional smoothness. These are often described as ‘feminised’ cultural traits, not because they belong to women but because they emphasise warmth, agreeableness and conflict avoidance. The result is predictable: disagreement goes underground. Colleagues who disagrees with you are more likely to block ideas, slow things down and subtly withhold information. The fact that they smile while doing it doesn’t mean it isn’t intra-organisational conflict.

In my research, I’ve found that guerilla wars between departments are pervasive, persistent and pernicious. They lead to weak, watered-down strategies that are implemented feebly, if at all. And yet, in the minority of teams, conflict is not only avoided but diverted into constructive challenges that strengthen strategy. Clearly, these differences are something that management researchers should investigate, which they have done, extensively. Their proximate explanation is that we align more strongly to our work group than to the wider organisation and, when disagreement arises, we take sides. This explanation rests on two substantial and well-established bodies of research. First, social identity theory: group membership shapes behaviour and in-group loyalty and out-group bias emerge rapidly. Second, resource dependence theory: power comes from resources, groups seek autonomy and this creates intra-organisational conflict. The scientific conclusion is sound, if unsurprising: a large life sciences company that is always one big happy team working together to improve human well-being is a fantasy.

Science is at its strongest when very different perspectives converge and, in this case, the organisational psychologists and the evolutionary anthropologists nod at each other in vigorous agreement. The evolutionary backbone of social identity theory is that humans evolved coalitional psychology: in ancestral environments, survival depended on alliances, shared labour and coordinated defence. Hence the tendency to form groups, favour in-group members and compete with out-groups.

Our minds evolved to detect group boundaries, conform to group norms and treat group membership as central to our identity. Moving from the savannah to the C-suite, departments inside companies behave the same way. They are not just organisational units, they are coalitions. Their members show the same in-group loyalty, out-group suspicion and resource competition that evolutionary psychologists describe. Get deep into this literature, as I have had to, and you quickly understand that social identity theory is not just a psychological model. It is a modern expression of ancient human behaviour.

If the science sounds hopeless, suggesting that departments are hard-wired to fight, I have some good news. We evolved to cooperate as well as to conflict. Human coalitions have always balanced the two. Groups compete when their interests diverge, but they collaborate when they share a fate. The management implication is simple. You cannot eliminate tribal dynamics, but you can shape them. Teams become happier and more cohesive when leaders reduce resource dependence, clarify decision rights and create shared meaning.

In practice, that means building strategy together, aligning incentives and removing the ambiguities that make people take sides. It also means recognising that harmony is not achieved by suppressing disagreement, but by creating conditions where disagreement strengthens rather than weakens the team. The most effective leaders do not pretend their colleagues are always aligned. They make alignment worth having. Harmony isn’t the absence of conflict. It is the presence of shared purpose. And, as ever, evolution shows us that coalitions thrive when they know what they are fighting for.