Team turns tribal
Sales against product, head office against the regions, and every meeting is about whose fault it is.
Rule out first
Genuinely conflicting incentives or targets. Unfair allocation of money or headcount. A merger with unresolved issues.
What could explain it
In-group bias: Ordinary favouritism that fades fast once people work on a shared goal or in mixed teams.
Social identity: People's sense of self is tied to the team; criticism of the team gets taken personally.
Basic assumption groups (Bion): The hostility rises with anxiety (a bad quarter, layoffs) and the group needs an enemy to hold together.
Destructive and abusive leadership: A leader on one side feeds the division to bind loyalty; it eases when that leader is absent.
Organisational justice: The division tracks a real unfairness in pay, credit or resources, and one side has a case.
Dehumanisation: animalistic and mechanistic (Haslam): Talk about the other team or the customers goes functional or crude ('the users', 'idiots', 'sales just wants'), they're credited only with basic feelings, and decisions that hurt them stop drawing discussion.
A next move
Set a shared goal that needs both sides to win, and check the incentives. Hostility that fades was bias; hostility that persists points to anxiety or a leader; a fair complaint from one side is a justice problem to fix.
If it’s you
Who is 'them' for me, and what do I get from having them?