• PNAs Express Submission
  • Sign up for PNAS eTOC alerts

Oxytocin enhances brain reward system responses in men viewing the face of their female partner

  1. René Hurlemanna,b,2
  1. Departments of aPsychiatry,
  2. bMedical Psychology, and
  3. dClinical Chemistry and Clinical Pharmacology, University of Bonn, 53105 Bonn, Germany;
  4. cKey Laboratory for Neuroinformation, School of Life Science and Technology, University of Electronic Science and Technology of China, 610054 Chengdu, China;
  5. eDepartment of Biopsychology, Ruhr University, 44780 Bochum, Germany; and
  6. fGerman Center for Neurodegenerative Diseases, 53175 Bonn, Germany

  1. Edited by Angela Sirigu, Centre National de la Recherche Scientifique, Bron, France, and accepted by the Editorial Board November 6, 2013 (received for review July 26, 2013)

Significance

Sexual monogamy is potentially costly for males, and few mammalian species along with humans exhibit it. The hypothalamic peptide oxytocin (OXT) has been implicated in mediating pair bonds in various species, but as yet, we know little about neurobiological factors that might act to promote fidelity, especially in men. Here we provide evidence for a mechanism by which OXT may contribute to romantic bonds in men by enhancing their partner's attractiveness and reward value compared with other women.

Abstract

The biological mechanisms underlying long-term partner bonds in humans are unclear. The evolutionarily conserved neuropeptide oxytocin (OXT) is associated with the formation of partner bonds in some species via interactions with brain dopamine reward systems. However, whether it plays a similar role in humans has as yet not been established. Here, we report the results of a discovery and a replication study, each involving a double-blind, placebo-controlled, within-subject, pharmaco-functional MRI experiment with 20 heterosexual pair-bonded male volunteers. In both experiments, intranasal OXT treatment (24 IU) made subjects perceive their female partner's face as more attractive compared with unfamiliar women but had no effect on the attractiveness of other familiar women. This enhanced positive partner bias was paralleled by an increased response to partner stimuli compared with unfamiliar women in brain reward regions including the ventral tegmental area and the nucleus accumbens (NAcc). In the left NAcc, OXT even augmented the neural response to the partner compared with a familiar woman, indicating that this finding is partner-bond specific rather than due to familiarity. Taken together, our results suggest that OXT could contribute to romantic bonds in men by enhancing their partner's attractiveness and reward value compared with other women.

Footnotes

  • ↵1D.S., A.W., and K.M.K. contributed equally to this work.

  • ↵2To whom correspondence should be addressed. E-mail: renehurlemann{at}me.com.

  • Author contributions: D.S., A.W., K.M.K., and R.H. designed research; D.S. and A.W. performed research; D.S., A.W., K.M.K., B.B., and R.H. analyzed data; B.S.-W. contributed new reagents/analytic tools; and D.S., A.W., K.M.K., B.S.-W., B.B., O.G., W.M., and R.H. wrote the paper.

  • The authors declare no conflict of interest.

  • This article is a PNAS Direct Submission. A.S. is a guest editor invited by the Editorial Board.

  • This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1314190110/-/DCSupplemental.

Online Impact