Why I’m nice and they’re not: oxytocin

You know what? Sometimes, after I meet a person for the first time and have some trivial conversation about hometowns and local weather, I walk away with a gut feeling that the person isn’t that nice. It’s always a mystery to me when this happens, because I’ll talk to this person for five minutes about mundane things, but for reasons I can’t put my finger on, I leave with a subtly negative opinion of the individual.

Sure, it could be that the person made poor eye contact or sighed one too many times…or maybe there’s a single gene that allows people to judge how nice you are within 20 seconds, depending on which version of the gene you have.

Yeah, that must be it.

This supposed “kindness” gene is the oxytocin receptor. This receptor allows messages to be transmitted by the hormone oxytocin, also known fondly as “the cuddle hormone.” Oxytocin decreases anxiety and promotes contentment and calmness; it is believed to facilitate bonding between mother and baby and between romantic partners. It has also been suggested that more sociable people might have higher oxytocin levels.

So it stands to reason that differences in the receptor for this hormone could have an impact on aspects of behavior; researchers at the University of Toronto, Canada set out to test this theory. They asked 116 volunteers to watch 23 video clips, each just 20 seconds long, of someone’s response to a partner telling a story of personal suffering. Afterwards, the volunteers rated the person’s kindness and trustworthiness.

Two general types of people were identified by the volunteers’ ratings: those who used significantly more non-verbal empathetic cues, like smiling and nodding, and those who…well, didn’t. As it turned out, the people who had a GG genotype in their oxytocin receptor (OXTR) were more likely to be judged as kind than those who had AG or AA genotypes. In other words…

The study has received some criticism because of the small number of videos that were used, but it will be interesting to see whether future studies find differences in oxytocin levels between people with different versions of the receptor, or whether the different receptor types transmit oxytocin messages in variable ways.

Not only has the GG version of this receptor been linked to empathy, but it’s also associated with greater optimism, higher levels of mastery, more self-esteem, and less depression. Now, as an aside, I will submit here that I have had personal genomics services provided by 23andMe, so out of curiosity I decided to go look and see which version of the oxytocin receptor I have (I’ve always felt like I’m empathetic to a fault). Lo and behold:

While this might just be some artifact of science and data gathering, I can’t help but feel that it’s pretty cool.

Stay nerdy

Lukas M, Toth I, Reber SO, Slattery DA, Veenema AH, & Neumann ID (2011). The neuropeptide oxytocin facilitates pro-social behavior and prevents social avoidance in rats and mice. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 36 (11), 2159-68 PMID: 21677650

Kogan A, Saslow LR, Impett EA, Oveis C, Keltner D, & Rodrigues Saturn S (2011). Thin-slicing study of the oxytocin receptor (OXTR) gene and the evaluation and expression of the prosocial disposition. Proceedings of the National Academy of Sciences of the United States of America PMID: 22084107

Saphire-Bernstein S, Way BM, Kim HS, Sherman DK, & Taylor SE (2011). Oxytocin receptor gene (OXTR) is related to psychological resources. Proceedings of the National Academy of Sciences of the United States of America, 108 (37), 15118-22 PMID: 21896752