Paradoxically, the most potent illustration of Shakespeare-as-genius manifested itself as an apparent challenge to it. How could the son of a glover with a provincial education have written so knowingly of kings and queens and faraway lands? It must have been another, dissenters said, with the Earl of Oxford emerging as a favorite candidate. What’s remarkable here is the underlying assumption that Shakespeare’s plays emerged entirely outside the give-and-take of the theater. Shakespeare doubters, the Cleveland State University scholar James Marino says, “are taking the lone genius idea and doubling down.”

Today, the Romantic genius can be seen everywhere. Consider some typical dorm room posters — Freud with his cigar, the Rev. Dr. Martin Luther King Jr. at the pulpit, Picasso looking wide-eyed at the camera, Einstein sticking out his tongue. These posters often carry a poignant epigraph — “Imagination is more important than knowledge” — but the real message lies in the solitary pose.

In fact, none of these men were alone in the garrets of their minds. Freud developed psychoanalysis in a heated exchange with the physician Wilhelm Fliess, whom Freud called the “godfather” of “The Interpretation of Dreams”; King co-led the civil rights movement with Ralph Abernathy (“My dearest friend and cellmate,” King said). Picasso had an overt collaboration with Georges Braque — they made Cubism together — and a rivalry with Henri Matisse so influential that we can fairly call it an adversarial collaboration. Even Einstein, for all his solitude, worked out the theory of relativity in conversation with the engineer Michele Besso, whom he praised as “the best sounding board in Europe.”

Now, from disparate directions, a new view of the self has been gathering steam that allows us to begin seeing these old stories as though for the first time. Many factors are at play, not least the rise of the Internet, both for its actual mechanisms that bring people together and for its potency as a metaphor. And the social science of relationships is flourishing, starting with the relational foundations of human development.

Consider what happens when 4-month-olds interact with their mothers: They mimic one another’s facial expressions and amplify them. A baby’s grin elicits a mother’s smile, which leads the baby to a full-on expression of joy — round mouth, big eyes. “Both parties,” writes the psychiatrist Susan C. Vaughan, “are processing an ongoing stream of stimuli and responding while the stimulation is still occurring.” The implication, Ms. Vaughan argues, is that emotions are “peopled” from the start, centered in an interpersonal exchange rather than in an atomized self.

This is just one piece of an impressive body of research in social psychology and the new field of social neuroscience, which contends that individual agency often pales next to the imperatives of a collective.

The elemental collective, of course, is the pair. Two people are the root of social experience — and of creative work. When the sociologist Michael Farrell looked at movements from French Impressionism to that of the American suffragists, he found that groups created a sense of community, purpose and audience, but that the truly important work ended up happening in pairs, as with Monet and Renoir, and Susan B. Anthony and Elizabeth Cady Stanton. In my own study of pairs, I found the same thing — most strikingly with Paul McCartney and John Lennon.