Oxytocin is a neurotransmitter that acts as a hormone. Often considered a major player in the regulation of trust and morality, its study is revealing fascinating information about human behavior and relationships. Oxytocin is released in the body when we feel safe and connected and tells the brain, “Everything is all right.” Dr. Paul Zak has determined that the human brain naturally produces oxytocin during breast-feeding, orgasm, hugs, snuggling, holding hands, partner dance, massage, bodywork, and prayer.

 

Humans have evolved as hyper-social creatures. Oxytocin helps us navigate our world of complex social relationships by rewarding positive social behavior with feelings of contentment and relaxation. As discovered by Zak and Theodoridou, oxytocin thus motivates a variety of pro-social behaviors such as generosity, compassion, and forgiveness. In other words, its presence in the brain helps us to trust and bond with strangers.

Oxytocin and Trust

This finding is related to another study orchestrated by Zak, in which he found that oxytocin increases a person’s likelihood to trust strangers and to give them money. In this study, participants were asked to give away a portion of $10 they had been given by researchers. The researchers found that participants who had been dosed with oxytocin were 80% more generous than control group participants. Participants in the oxytocin condition were more trusting of the strangers they encountered.

 

Oxytocin and Relationships

Ditzen and colleagues designed a study using couples and found that those treated with synthetic oxytocin had far lower stress levels. Participating couples were asked to discuss a topic that was stressful and had consistently triggered conflict between them in the past. Then, researchers measured the presence of stress hormones within their bodies. They found that oxytocin improved positive communication between couples and was also related to a decrease in the presence of cortisol, a hormone associated with stress and with our flight-or-fight reflex. According to Grewen, partners with higher naturally occurring oxytocin rates also score higher on measures of partner support.

Learning about oxytocin has given me insight into my interactions with other people. One of my friends often jokes about my poor taste in men. When we are out together and I point out someone mildly attractive or “cute,” she always disagrees and voices how unappealing he is to her. We also have very different personalities. Where I am very affectionate with people I am close to, she is more reserved. Research by Theodoridou and colleagues showed that participants who were given synthetic oxytocin were more likely to perceive strangers as attractive and trustworthy when compared to control participants not dosed with oxytocin. I often wonder if the differences in personality and dating preferences between us may be governed by differences in the levels of oxytocin pumping through our bodies.

Recalling happy faces

Oxytocin and Memories

One of my favorite oxytocin studies shows that this cuddle hormone affects our ability to encode and recall memories. Guastella and colleagues conducted a study on volunteers and the role of oxytocin in recalling faces with happy, angry, or neutral facial expressions. Previous research by Vuilleumier had shown that human beings have a bias towards recognizing negative facial expressions more than neutral or positive ones, and Surguladze had found a dramatic increase of this effect in populations of depressed people.

Guastella’s research showed that people who received oxytocin countered this tendency and were more likely to recognize and recall happy faces. This result shows that oxytocin can impact how we perceive the world and might allow us to recognize and appreciate positive thoughts and experiences that we normally overlook.

Go hug someone

So What Does This Mean to Us?

How can we take greater advantage of naturally occurring oxytocin and maximize its release in our own bodies? Oxytocin is found only in mammals and needs stimulation to be released. According to Wellsphere, studies have revealed that the use of social media can facilitate the release of oxytocin and that even thinking about someone who loves you or someone you deeply care for is enough to activate the release of oxytocin.

However, physical touch stimulates the most potent release of oxytocin. In a TED Talk, Dr. Zak prescribes at least 8 hugs per day to feel happier and more connected, as well as to nurture relationships. According to Zak, research into relationships has shown that higher oxytocin levels are associated with improved heart health, especially in women. Furthermore, after only 20 seconds of hugging a romantic partner, one can achieve a spike in oxytocin levels, as well as a decrease in blood pressure, heart rate, and cortisol levels. So do yourself a favor—go hug someone!

References:
Barraza, J. A., McCullough, M. E., Ahmadi, S. & Zak, P. J. (2011). Oxytocin infusion increases charitable donations regardless of monetary resources. Hormones and Behavior, 60(2), 148-151. DOI: 10.1016/j.yhbeh.2011.04.008

Ditzen, B. et al. (2009). Intranasal Oxytocin Increases Positive Communication and Reduces Cortisol Levels During Couple Conflict. Biological Psychiatry, 65, 728-73. Abstract.

Grewen, K. M., Girdler, S. S., Amico, J. & Light, K. C. (2005). Effects of partner support on resting oxytocin, cortisol, norepinephrine, and blood pressure before and after warm partner contact. Psychosomatic Medicine, 67(4), 531-538. Abstract.

Guastella, A. J., Mitchell, P. B. & Mathews, F. (2008) Oxytocin Enhances the Encoding of Positive Social Memories in Humans. Biological Psychiatry, 64(3), 256–258. Abstract.

Light K. C., Grewen, K. M. & Amico, J. A. (2005). More frequent partner hugs and higher oxytocin levels are linked to lower blood pressure and heart rate in premenopausal women. Biological Psychology, 69(1), 5-21. Epub 2004 Dec 29. Abstract.

Mikolajczaka, M., Pinonb, N., Lanea, A., de Timaryc, P. & Lumineta, O. (2010). Oxytocin not only increases trust when money is at stake, but also when confidential information is in the balance. Biological Psychology, 85, 1, 182–184. Abstract.

Surguladze S. A., Young, A. W., Senior, C., Brébion, G., Travis, M. J. & Phillips, M. L. (2004).Recognition accuracy and response bias to happy and sad facial expressions in patients with major depression. Neuropsychology.;18(2):212-8.

Theodoridou, A., Rowe, I., Penton-Voak, I., Rogers, P. (2009). Oxytocin and social perception: Oxytocin increases perceived facial trustworthiness and attractiveness. Hormones and Behavior, 56,1, 128–132.

Vuilleumier, P. (2002). Facial expression and selective attention. Current Opinion in Psychiatry, 15:291-30.

Wellsphere 2010: ssssssa

Zak P. J., Stanton, A. A. & Ahmadi, S. (2007) Oxytocin Increases Generosity in Humans. PLoS ONE 2(11): e1128. doi:10.1371/journal.pone.0001128

Zak, P. J. (2008). The Neurobiology of Trust. Scientific American.

Zak, P. J. (2011). Trust, Morality – and Oxytocin. TED Talk.

Images
Mother and child courtesy of Jeff Snodgrass
Just you and I courtesy of Miran Rijavec
Recalling happy faces courtesy of Rufino
Celebratory hug courtesy of Sergio Bertolini

Edited by Natasha Utevsky