APA Citation
De Dreu, C., Greer, L., Handgraaf, M., & others, . (2010). The neuropeptide oxytocin regulates parochial altruism in intergroup conflict among humans. *Science*, 328(5984), 1408-1411.
Summary
This groundbreaking study reveals that oxytocin, often called the "bonding hormone," has a complex dark side in human relationships. While oxytocin promotes cooperation and bonding within groups, it simultaneously increases hostility and aggression toward outsiders. The research demonstrates that oxytocin doesn't create universal love and empathy, but rather strengthens in-group loyalty while amplifying discrimination against those perceived as different or threatening. This dual nature of oxytocin helps explain how intimate relationships can involve both intense bonding and destructive dynamics.
Why This Matters for Survivors
This research helps survivors understand the neurobiological underpinnings of trauma bonding and why leaving abusive relationships can feel so difficult. The same hormone that creates intense attachment to an abusive partner also fuels hostility toward potential helpers, family members, or friends who try to intervene. Understanding oxytocin's role validates survivors' experiences of feeling powerfully drawn to their abuser while simultaneously isolating from their support network.
What This Research Establishes
Oxytocin creates in-group loyalty while simultaneously increasing out-group hostility, revealing why trauma bonding involves both intense attachment to abusers and rejection of potential helpers.
The “love hormone” narrative is dangerously incomplete, as oxytocin can fuel discrimination, aggression, and isolation tactics that characterize abusive relationship dynamics.
Neurobiological bonding mechanisms can be weaponized in relationships, explaining why intermittent reinforcement and love-bombing create such powerful psychological and physical dependencies.
Social isolation isn’t just a psychological tactic but has neurochemical underpinnings, as oxytocin makes survivors more suspicious and hostile toward those trying to help them escape abuse.
Why This Matters for Survivors
Understanding oxytocin’s dual nature helps explain why your bond with an abusive partner felt so real and powerful—because it was. The same hormone that creates mother-infant bonds and deep friendships was actively working to attach you to someone who was hurting you. This wasn’t weakness or poor judgment; it was biology.
This research validates the confusing experience of feeling drawn to your abuser while simultaneously pushing away people who genuinely cared about you. Your brain was literally wired to see your support system as threats and your abuser as safety, even when logic told you otherwise. This neurobiological hijacking is a feature of abuse, not a bug.
The intensity of trauma bonding isn’t evidence that the relationship was special or meant to be—it’s evidence of how skillfully narcissistic abusers exploit our attachment systems. The love-bombing phases weren’t genuine love but calculated manipulation designed to trigger maximum oxytocin release and strengthen your dependence.
Recovery involves understanding that breaking trauma bonds requires time for your neurochemistry to rebalance. The pull you feel toward your abuser and the suspicion you feel toward helpers will fade as your brain rewires itself, but this process requires patience, no-contact when possible, and professional support.
Clinical Implications
Clinicians working with survivors must recognize that trauma bonding involves real neurobiological changes that can’t be reasoned away through insight alone. The oxytocin system creates physiological withdrawal symptoms when survivors separate from abusers, requiring medical and therapeutic support similar to addiction treatment protocols.
Understanding oxytocin’s role in out-group hostility helps explain why survivors often resist therapeutic interventions and view helping professionals with suspicion. This resistance isn’t treatment non-compliance but a neurobiological response that requires gentle, patient therapeutic approach focused on safety and trust-building over time.
The research supports the importance of no-contact protocols in recovery, as continued exposure to the abuser continues to trigger oxytocin release and maintain trauma bonds. Clinicians should educate clients about the neurobiological basis of trauma bonding to reduce self-blame and normalize the recovery process.
Treatment protocols should address both the addiction-like aspects of trauma bonding and the social isolation that oxytocin-driven out-group hostility creates. This may involve gradual exposure to supportive relationships while the neurochemical system rebalances, combined with psychoeducation about the biological basis of their experiences.
How This Research Is Used in the Book
Chapter 12 explores how narcissistic abusers exploit neurobiological attachment systems to create dependency and isolation. The oxytocin research provides crucial scientific backing for understanding why trauma bonds feel so real and why recovery takes significant time and effort.
“When Sarah described feeling ‘addicted’ to her narcissistic partner despite knowing he was destroying her life, she wasn’t speaking metaphorically. The oxytocin surges during their reconciliation periods created genuine neurochemical highs, while simultaneously making her family and friends—who were trying to help her leave—feel like threats to be avoided. Understanding this dual action of oxytocin helped Sarah realize that her intense bond with her abuser and her rejection of support weren’t character flaws but biological responses to calculated manipulation.”
Historical Context
Published in Science in 2010, this research fundamentally challenged the popular portrayal of oxytocin as purely a “love hormone” that promotes universal bonding and empathy. The study emerged during the early 2010s surge in neuroeconomics and social neuroscience, when researchers were beginning to understand the complex, often dark sides of neurobiological systems previously viewed as wholly positive. This work laid important groundwork for understanding how attachment mechanisms can be exploited in toxic relationships.
Further Reading
• Dutton, D. G., & Painter, S. (1993). Emotional attachments in abusive relationships: A test of traumatic bonding theory. Violence and Victims, 8(2), 105-120.
• Carter, C. S. (2014). Oxytocin pathways and the evolution of human behavior. Annual Review of Psychology, 65, 17-39.
• Stanger, C., et al. (2013). Neuroeconomics and adolescent substance abuse: Individual differences in neural networks and delay discounting. Journal of the American Academy of Child & Adolescent Psychiatry, 52(7), 747-755.
About the Author
Carsten K. W. De Dreu is Professor of Psychology at Leiden University and the University of Amsterdam, renowned for his research on social conflict, cooperation, and the neurobiological bases of human behavior. His work bridges social psychology and neuroscience to understand how hormones influence group dynamics.
Lindred L. Greer is Professor of Organizational Behavior at London Business School, specializing in team dynamics and conflict resolution in organizational settings.
Historical Context
Published in 2010, this research challenged the popular narrative of oxytocin as purely a "love hormone." The study emerged during a period of growing interest in neuroeconomics and the biological basis of social behavior, fundamentally shifting understanding of how attachment systems can be weaponized in abusive dynamics.
Frequently Asked Questions
Oxytocin creates powerful bonds during intimate moments with abusers while simultaneously making survivors more hostile toward potential helpers, creating a neurobiological trap that makes leaving extremely difficult.
The same oxytocin that bonds them to their abuser also increases suspicion and hostility toward outsiders, making well-meaning supporters seem threatening or untrustworthy.
Trauma bonding involves real neurobiological changes driven by hormones like oxytocin. It's not weakness but a survival mechanism that gets hijacked in abusive relationships.
Yes, understanding the biological basis of trauma bonds helps survivors recognize their experiences as normal responses to abnormal situations, reducing self-blame and shame.
Narcissists use love-bombing, intermittent reinforcement, and isolation tactics that trigger oxytocin release during positive moments while strengthening bonds and increasing hostility toward outside support.
Oxytocin increases empathy toward in-group members while simultaneously decreasing empathy toward outsiders, making it a double-edged sword in relationships.
The honeymoon phase triggers massive oxytocin release after periods of stress, creating addictive neurochemical highs that strengthen the trauma bond with the abuser.
Trauma bonds can take months to years to fully weaken as the brain rewires itself, which is why no-contact periods are crucial for recovery and why survivors often return multiple times.