Hormone: Role of Oxytocin in Human Fidelity 

Hormones are chemical messengers that are released in the bloodstream, it has no voluntary control and has long-term processes such as growth, metabolism, and reproduction. Also, it Is part of our endocrine system. Hormones can only produce reactions in certain cells (target cells) that have an appropriate receptor site for the hormones. When the hormone binds to the target cell, it either increases or decreases its function. One example of a hormone is oxytocin. Oxytocin is also known as the “cuddle hormone” or “love hormone” as it seems to play a role in social bonding, attachment, and trust. It is produced by the hypothalamus and secreted by the pituitary gland in the endocrine system.  For women, oxytocin plays a role in the processes of childbirth, lactation, and Mother-child attachment, and for men, it may have a role in modulating sexual and social behavior. One study that demonstrated the role of oxytocin in human fidelity is Scheele et al. (2012).  

The researchers conducted a lab experiment with a double-blind independent measure design to investigate if oxytocin modulates social distance between men and women. The participants were heterosexual men who were in stable monogamous relationships and singles. Participants were allocated into two groups: oxytocin nasal spray and placebo nasal spray group. Then they were given two independent tasks: stop distance paradigm and approach/avoidance task. In the stop distance task, participants were positioned at one end of the room while an attractive female experimenter was positioned on the other side of the room. The participants were required to move slowly toward the female experimenter and stop at a distance that made them feel slightly uncomfortable. In the approach/avoidance task, the participants viewed a series of pictures on a screen with their heads positioned on a chin rest at a viewing distance of 50 cm. There were 4 types of pictures shown in random order: positive social (attractive women), positive non-social (beautiful landscapes), negative social (mutilations), and negative non-social (dirt). All participants had a joystick and if they liked the picture, they would pull the joystick towards them and if they didn't, they would push the joystick away from them. It was found that in the first task, oxytocin stimulated men in monogamous relationships, but not single ones, to keep a greater distance between themselves and an attractive woman, and in the second task, the only group of pictures affected by oxytocin and relationship status was the positive social group. Specifically, participants who received oxytocin had a slower reaction time in response to these pictures, but only if they were in a relationship.

Hence, the researchers concluded that oxytocin causes men in a relationship to “stay away from” an attractive woman who is not their partner and selectively inhibits the approach to certain stimuli in men who are in a stable relationship but not in single men. In conclusion, oxytocin may promote fidelity.