When Friend Groups Change, So Do Friendships

Key points

When a duo becomes a trio, emotional bonds shift—and one friend often ends up feeling left out.

Friendships lack clear rules, making boundary-crossing and unspoken hurt common in group dynamics.

Echo chambers and mutual validation can replace empathy, fueling blame over reflection.

Each year for the past decade, I have taught a course called "The Psychology of Relationships" at the University of Toronto, and over the past several years, I’ve noticed a subtle but important shift: Students are asking more and more questions about friendships compared to romantic relationships . And one recurring theme across both students and forums relating to friendships alike is how complicated friendships become for members in a group of three.

The Challenge of Group Dynamics

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