What is the oxytocin controversy?
Oxytocin is a hypothalamic neuropeptide widely referred to as the “love hormone.” It has a well-established reputation as a hormone that elevates feelings of attachment and connection, trust and intimacy: Giddy with love often means giddy with oxytocin. Defined as such, oxytocin appears to support the bonding that takes place in romantic relationships.
1. People engaging in nonverbal expressive displays of love have higher levels of oxytocin, potentially revealing oxytocin’s role in promoting a desire to affiliate (Gonzaga, Turner, Keltner, Campos, & Altemus, 2006).
2. Oxytocin levels may help men who are in committed relationships stay bonded to their partners. Monogamous heterosexual men were shown photos of women and oxytocin increased the perceived attractiveness of only the photo of their own romantic partner while activating the reward system in their brains (Scheele et al., 2013).
3. Research on genetic variations that correspond with the secretion of oxytocin has shown that propensity for higher oxytocin positively predicts feelings of love, romantic relationship satisfaction, and both the frequency of and quality of gratitude (Algoe & Way, 2014). Given the positive role of gratitude in romantic relationship maintenance, these findings support a bonding role of oxytocin.
Accumulating evidence, however, suggests that oxytocin might be better understood as part of the stress-response system or at minimum, as a marker of distress. Instead of pulling two people together, oxytocin may be called to action during times that threaten love relationships.
1. A link between romantic attachment anxiety and levels of plasma oxytocin supports the tentative conclusion that oxytocin levels may rise in response to relationship anxiety (Marazziti et al., 2006)
2. Higher levels of oxytocin after a stressful interpersonal task were associated with more anxiety and less forgiveness, suggesting that oxytocin is a marker for distress (Tabak, McCullough, Szeto, Mendez, & McCabe, 2011).
3. Instead of support for the idea that oxytocin would be elevated during positive couple interactions, Smith and colleagues (2013) found tentative evidence that higher levels of oxytocin were associated with lower levels of relationship quality.
Testing the controversy
This diverse landscape of oxytocin research precludes a clear understanding of whether we should expect oxytocin levels to be higher in happy couples or distressed couples. Luckily, a new study out of Utah directly examined this puzzle and offers a clear articulation of what is really happening with oxytocin and romantic relationships (Holt-Lunstad, Birmingham, & Light, 2014).
Holt-Lunstad and colleagues (2014) recruited both members of 34 married couples, all of whom were screened for existing health problems, and over four weeks obtained multiple oxytocin readings and asked participants to complete a variety of relationship measures.
They found that relationship quality was positively associated with oxytocin. Within the sample, about one third of the couples could be categorized as distressed, and for these couples, distress was associated with lower not higher levels of oxytocin. It’s love, not distress, that seems to go hand-in-hand with oxytocin.
This study is particularly compelling because it measured oxytocin both through plasma and saliva, maintained the relational context by studying both partners together, and took place over a period of time, controlling for stress and depression levels. By imposing these controls, unrelated stress responses of oxytocin were controlled, making it possible to see the correspondence between a healthy and well-adjusted marital relationship and oxytocin, even in distressed couples (where levels of oxytocin were lowest).
In the end, it seems that higher quality relationship function is linked to more oxytocin, not less. Oxytocin remains the love hormone after all.
Algoe, S. B., & Way, B. (2014). Evidence for a role of the oxytocin system, indexed by genetic variation in CD38, in the social bonding effects of expressed gratitude. Social Cognitive and Affective Neuroscience. Advanced online publication.
Gonzaga, G. C., Turner, R. A., Keltner, D., Campos, B., & Altemus, M. (2006). Romantic love and sexual desire in close relationships. Emotion, 6, 163-179.
Holt-Lunstad, J., Birmingham, W. C., & Light, K. C. (2014). Relationship quality and oxytocin Influence of stable and modifiable aspects of relationships. Journal of Social and Personal Relationships. Advanced online publication.
Marazziti, D., Dell'Osso, B., Baroni, S., Mungai, F., Catena, M., Rucci, P., ... & Dell'Osso, L. (2006). A relationship between oxytocin and anxiety of romantic attachment. Clinical Practice and Epidemiology in Mental Health, 2(1).
Scheele, D., Wille, A., Kendrick, K. M., Becker, B., Güntürkün, O., Maier, M., & Hurlemann, R. (2013). Oxytocin alters the human reward system to maintain romantic love. Pharmacopsychiatry, 46- A93.
Smith, T. W., Uchino, B. N., MacKenzie, J., Hicks, A. M., Campo, R. A., Reblin, M., ... & Light, K. C. (2013). Effects of couple interactions and relationship quality on plasma oxytocin and cardiovascular reactivity: empirical findings and methodological considerations. International Journal of Psychophysiology, 88, 271-281.
Tabak, B. A., McCullough, M. E., Szeto, A., Mendez, A. J., & McCabe, P. M. (2011). Oxytocin indexes relational distress following interpersonal harms in women. Psychoneuroendocrinology, 36, 115-122.