Neurobiology and Genetics of Pair Bonding: A New Hypothesis

Many forms of love, from intimate friendships to obsessive attachment, are characterized by a pattern of synchronous and increased behavioral activity and increased neural activity in the mesolimbic dopamine system. This suggests that dopamine neurons may play an important role in mediating and rewarding behaviors that are contingent on the presence of a social partner. This hypothesis is based on the fact that dopamine neurons are responsive to social stimuli and reward stimuli associated with social behavior and are altered by social experience. Importantly, there is increasing evidence that dopamine plays a key role in mediating many forms of social behavior. The dopamine system has a high density of dopamine receptors in regions involved with reward processing and reinforcement learning, such as the striatum. These regions may mediate the reinforcing effects of social interaction and possibly mediate some forms of social attachment, such as those involved in pair bonding. Future research that tests this hypothesis will have important implications for understanding the neural substrates of the natural rewards associated with the formation and maintenance of attachments to other individuals , which could provide important insights into the neural mechanisms involved in psychiatric disorders.