CREATISTA / locrifa / Shutterstock / The Atlantic In the hierarchy of relationships, friendships are at the bottom. Romantic partners, parents, children—all these come first. This is true in life, and in science, where relationship research tends to focus on couples and families. When Emily Langan, an associate professor of communication at Wheaton College goes to conferences for the International Association of Relationship Researchers, she says, “friendship is the smallest cluster there.