The transient joys of others—neural ensembles encode social approach in bonded voles

Social bonds are an essential part of the human experience. We bond with our parents, our children, our romantic partners, and our friends; these bonds not only shape our emotional well-being but have profound consequences for our health and longevity (1). Perhaps because these bonds are so profoundly important, we often imagine them to be uniquely human. They are not. Indeed, much of what we know about human bonding has its origins in animal behavior. In the first volume of Attachment and Loss , John Bowlby (2) drew on the ethological work of Konrad Lorenz to formulate attachment theory, a conceptual framework that continues to inform social psychology some 50 y later (3). In subsequent decades, work on the pair-bonding prairie vole has revealed the role of the brain’s reward circuits in bonding (4). A study by Scribner et al. (5) explores how these bonds are manifest in the changing patterns of neural activity within the brain’s reward system, work that promises broad insights into the mechanisms of attachment.Prairie voles are small rodents that live in the greater Midwest, ranging from Saskatchewan to Oklahoma, and from Colorado to West Virginia. In the 1970s, researchers noticed that they often caught specific males and females together in the same traps and suspected that such pairs were bonded mates (6). We now know that the repeated mating of a pair over the course of a day leads to a bond; males and females share a nest, a territory, as well as the care of their young, but this familial commitment does not always translate into sexual fidelity—a pattern of behavior known as “social monogamy” (7⇓–9).Some of our first insights into the neurobiology of attachment came from the realization that the socially monogamous prairie vole differs from its … [↵][1]1To whom correspondence may be addressed. Email: sphelps{at}mail.utexas.edu. [1]: #xref-corresp-1-1