During teenage years, the brain undergoes important structural changes that set the stage for adult decision-making abilities. This study found that a cell adhesion protein called β1-integrin plays a critical role during adolescence in stabilizing connections between brain cells in the prefrontal cortex. When this protein was missing during the teenage years, adult mice struggled to make good decisions about rewards and could not adjust their behavior when circumstances changed. The research suggests that proper brain development during adolescence requires these cellular adhesion molecules to build the neural circuits needed for intelligent decision-making later in life.