How to use psychology to shift a difficult relationship into a healthier one

Relationships can feel like both a blessing and the bane of your existence, a source of joy and a source of frustration or resentment. At some point, each of us is faced with a clingy child, a dramatic friend, a partner who recoils at the first hint of intimacy, a volatile parent, or a controlling boss—in short, a difficult relationship.

As a psychology professor and relationship scientist, I’ve spent countless hours observing human interactions, in the lab and in the real world, trying...