This week, a paper came out looking at testosterone levels in fathers. A whirlwind of poor journalism followed, which was beautifully smacked down by William Saletan over at Slate (aslo: see this great post on the topic by our very own Kate Clancy). But it reminded me of a similar kerfluffle that occurred this past January over a paper on the effects of sniffing tears. This was my post from Jan 8th on that paper and the media surrounding it, which just so happens to look at the meaning of lowered testosterone levels in terms of evolution.
I don’t think Brian Alexander is a bad guy or a misogynist. He writes the Sexploration column for MSNBC, so sure, his job is all about selling sex stories to the public. He even wrote a book about American sexuality. But I don’t personally think he has a burning hatred for women, or views them as objects placed on this Earth for the sexual satisfaction of men. However, I very easily could, given how he chose to report on a recent study published in Science about men’s physiological responses to the chemicals present in women’s tears.
The headline alone was enough to make me gag — “Stop the waterworks, ladies. Crying chicks aren’t sexy.” The sarcastic bitch in me just couldn’t help but think Why THANK YOU Brian! I’ve been going about this all wrong. When I want to get some from my honey, I focus all my thoughts on my dead dog or my great grandma and cry as hard as I can. No WONDER it isn’t working!
I didn’t even want to read the rest of the article.
But I did.
It doesn’t get better.
Alexander’s reporting of the actual science was quick and simplistic, and couched in sexist commentary (like how powerful women’s tears are as manipulative devices). 
And to finish things off, he clearly states what he found to be the most important find of the study:
“Bottom line, ladies? If you’re looking for arousal, don’t turn on the waterworks.”
It’s no wonder that the general public sometimes questions whether science is important. If that was truly the aim of this paper, I’d be concerned, too!
Of course, Brian Alexander missed the point. This paper wasn’t published as a part of a women’s how-to guide for getting laid. Instead, the authors sought to determine if the chemicals present in human tears might serve as chemosignals like they do for other animals — and they got some pretty interesting results.
In many species, chemical signals run rampant. Scents, pheromones, and other chemical cues are deliberately and unconsciously given off to tell other individuals anything from “Back Off – MY Tree!” to “Hop on and ride me, baby!” But despite how common they are in the rest of the animal kingdom, the function of chemical signals in humans is hotly debated. Years of searching has yet to find human pheromones (no matter what those websites tell you), and while scent seems to play a role in communication in people, there is still relatively little knowledge as to what chemicals and why.
Given that tears are known to serve as sexual signals in mice, it isn’t strange at all that Noam Sobel and his team chose to look at the physiological responses to tears. The Israeli team designed an impressive and unbiased set of experiments to determine if the tears produced by women when sad elicit physiological responses in men separate of the visual or auditory stimuli of a woman crying.
To find out if tears alone acted as chemosignals, the scientists collected tears from women watching tear-jerkers, and as a control, compared their effects to saline rolled down women’s cheeks. Men sniffed the solutions without any knowledge as to what they were during a series of different experiments. In the first, men with a tear-soaked pad under their nose were asked to rate the sexual attractiveness and mood of female faces. While the smell of saline had no effect, men inhaling Eau de Tears consistently rated women’s faces as less attractive, though this had no impact on whether they found the faces happy or sad.
For the second experiment, men sniffed tears before watching a sad movie. While doing so didn’t affect their mood, the smell of tears did elicit a physiological response: men’s faces became more conductive to electricity, which happens when we sweat and is indicative of a psychological reaction. Furthermore, the men self-reported less sexual arousal, which was reflected in their bodies as a 13% drop in saliva testosterone levels.
But to really get to the meat of it, the team threw their male test subjects into an fMRI machine and scanned their brains for activity while sniffing tears. Researchers saw much less activity in the hypothalamus and the fusiform gyrus, both of which are thought to be involved in sexual arousal. All three experiments lead to the same conclusion: the chemicals in women’s emotional tears reduce male sex drive.
The real question, though, is why? Why do men’s testosterone levels tank at the smell of a woman’s tears? The overwhelming answer given by mainstream media (as Rheanna pointed out) is that tears just aren’t sexy. When women cry, so the journalists say, it’s a chemical signal that they don’t want to have sex. Because evolution is all and only about sex… right?
Sorry to burst their bubble, but even when it comes to evolution, it’s not all about sex. Selection also favors survival — because, you know, you can’t have sex when you’re dead*. Thus women’s tears are not necessarily evolutionarily intended to turn guys off. For example, Ed Yong brings up the hypothesis that tears might be used to downplay aggression. Think about it: we cry when we’re sad or physically in pain. In both cases, we’re more vulnerable. Getting others, especially angry men, to be less aggressive towards us in that moment could certainly be a benefit to survival.
Really, the idea that tears are intentionally used as a turn off is a hard sell to an evolutionary biologist. What benefit do women get from not having sex when crying? Does it somehow make them have healthier or more babies? Not for any reason I can think of.
There is, instead, an even more intriguing explanation, one that makes a whole lot more sense. Many who wrote about this paper (including Brian Alexander) mentioned that tears are known to contain a variety of compounds, including prolactin, the hormone which is responsible for making a guy cool his jets after he gets off. But prolactin does much more than ensure a guy stops going at it — it’s a hugely important hormone for nurturing behaviors. In fact, the connection between reduced testosterone and nurturing/bonding behaviors may be the real reason as to why men’s testosterone levels dip upon sniffing tears.
Numerous studies have shown that parental and nurturing behaviors are mediated by prolactin while inhibited by testosterone. For example, research has shown that prolactin levels positively and testosterone levels negatively correlate with a father’s impulse to respond to a baby’s cry. Furthermore, men’s prolactin levels spike and testosterone levels drop in the weeks before their partner gives birth.
It goes beyond babies, too. Decreased testosterone and increased prolactin are strongly implicated in establishing and maintaining relationships. Monogamous men have significantly lower testosterone levels and higher prolactin levels than their single brethren. Furthermore, studies have directly shown that artificially increasing testosterone in a double-blind, placebo-controlled setting makes men less generous to strangers and reduces a person’s empathy for others.
Perhaps prolactin or other chemical signals in tears are directly targeting and activating the nurturing pathway in men’s brains. Being taken care of or protected when in emotional or physical pain would definitely benefit an individual’s survival. Personally, I would like to see this study of tears replicated to determine women’s responses to the scent as well as men’s reactions when using men’s and children’s tears, as well as looking at the levels of prolactin, oxytocin, and other well-established bonding and empathetic hormones. My bet is the response isn’t limited to men, and isn’t limited to emotional secretions from women.
While Brian Alexander and the rest of the sensationalists seem to suggest the signal is “I’m not in the mood,” its likely that the message has nothing to do with having or not having sex. Women aren’t saying “back off” — they’re saying “help me.”
Why do I care so much? It’s not just that they got it wrong. It’s that their interpretation of research isn’t labeled as opinion. It’s that the vast majority of people who have any interest in science news are going to read inaccurate (if not downright insulting) news articles and think studies like this one are either misogynistic or frivolous. It’s that journalists like Brian Alexander undermine good science for the sake of attention grabbing headlines. And as a scientist and a writer, it’s a double insult.
Gelstein, S., Yeshurun, Y., Rozenkrantz, L., Shushan, S., Frumin, I., Roth, Y., & Sobel, N. (2011). Human Tears Contain a Chemosignal Science DOI: 10.1126/science.1198331
* I can hear the comments now, you sickos, so let me clarify: you can’t have baby-producing sex when you’re dead.
Also, thanks to Kira Krend for the thoughtful and hilarious discussion on this topic!
Other References:
- Haga S, Hattori T, Sato T, Sato K, Matsuda S, Kobayakawa R, Sakano H, Yoshihara Y, Kikusui T, & Touhara K (2010). The male mouse pheromone ESP1 enhances female sexual receptive behaviour through a specific vomeronasal receptor. Nature, 466 (7302), 118-22 PMID: 20596023
- Fleming, A. (2002). Testosterone and Prolactin Are Associated with Emotional Responses to Infant Cries in New Fathers Hormones and Behavior, 42 (4), 399-413 DOI: 10.1006/hbeh.2002.1840
- Storey AE, Walsh CJ, Quinton RL, & Wynne-Edwards KE (2000). Hormonal correlates of paternal responsiveness in new and expectant fathers. Evolution and human behavior : official journal of the Human Behavior and Evolution Society, 21 (2), 79-95 PMID: 10785345
- Burnham, T. (2003). Men in committed, romantic relationships have lower testosterone Hormones and Behavior, 44 (2), 119-122 DOI: 10.1016/S0018-506X(03)00125-9
- Zak, P., Kurzban, R., Ahmadi, S., Swerdloff, R., Park, J., Efremidze, L., Redwine, K., Morgan, K., & Matzner, W. (2009). Testosterone Administration Decreases Generosity in the Ultimatum Game PLoS ONE, 4 (12) DOI: 10.1371/journal.pone.0008330
- HERMANS, E., PUTMAN, P., & VANHONK, J. (2006). Testosterone administration reduces empathetic behavior: A facial mimicry study Psychoneuroendocrinology, 31 (7), 859-866 DOI: 10.1016/j.psyneuen.2006.04.002
