Oxytocin, Fidelity and Sex

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Can a guy keep himself faithful by jacking up oxytocin?

"A study published Tuesday in the Journal of Neuroscience has uncovered a surprising new property of oxytocin, finding that when men in monogamous relationships got a sniff of the stuff, they subsequently put a little extra space between themselves and an attractive woman they'd just met," wrote the LA Times recently.

The results surprised researchers. They had assumed oxytocin would make all men inch closer to cute females. Instead men in committed relationships moved farther away when dosed with oxytocin (and only when dosed). It's more evidence that pair-bonding is biological not cultural.

Yet how could "the love hormone" make men subconsciously keep their distance from attractive, novel mates? The answer is fascinating. Before we consider how men who want to stay happily mated might keep their oxytocin at optimum levels, let's briefly consider the evolutionary roots and biological underpinnings of pair bonding itself. They bear upon the answer.

Experts believe that pair bonding (only 3-5% of mammal species) evolved from the same mechanisms that are behind the mammalian infant-caregiver bond. As explained more fully in The Lazy Way to Stay in Love, the bond between infant and caregiver is created, and strengthened, via bonding behaviors (formally known as attachment cues).

To form a tight bond—even between infant and caregiver—these behaviors need to occur almost daily for an extended period. Eventually the brain can wire up a lasting association of comfort with a particular person/mammal (bond). Unless it is broken by harsh weaning or other stress, or replaced with a new bond, it can last a lifetime. This is how we can come to dote on our parents, kids, pets...and even, if we're lucky, our mate.

Bonding basics

The mechanics behind the power of attachment cues are dead simple. These familiar behaviors (skin-to-skin contact, eye contact, affectionate touch, nurturing, etc.) release oxytocin in a part of the brain known as the amygdala and relax it. Without this neurochemically induced ease, we don't bond. We remain on guard.

Moreover, if too much relationship stress consistently overpowers the effects of oxytocin in the amygdala, bonds fray. This is because the amygdala's job is to keep our defenses up unless we feel safe(i.e., relaxed). Obviously, the more precarious our childhood bonds, the more soothing we need before we truly feel safe, and the more readily we (over)react to current relationship stress.

Oxytocin, at just the right levels in just the right brain circuits, is a powerful means of keeping our defenses down between us and anyone to whom we attach. Yet there's also another element to bonding: desire, which is powered by dopamine. That's where sexual intimacy and flirting enter the equation. (More in a moment.)

Back to oxytocin. Just as too little oxytocin inhibits bonds, so does too much. Thus, a synthetic overdose of oxytocin can cause pair bonders not to bond. (This paradoxical effect probably has to do with the types of receptors that oxytocin, and the neurochemicals it triggers, bind to—depending upon quantity released.) 

Oxytocin can also make mammals defensive of their young, and aggressive toward outsiders. In fact, both male and female pair-bonded prairie voles sometimes attack other stray adults of the opposite sex. Since oxytocin (and its close neurochemical cousin, vasopressin) is behind this "us v. them" behavior, it's not all that surprising that a hit of oxytocin can make a mated human male keep a bit of distance between himself and unknown adult females.

Incidentally, the nasal spray used in oxytocin experiments is not a viable way to promote fidelity. Nasty, unintended side effects have occurred when oxytocin is squirted up the nose into the brain over extended periods.

The key point is that in mammalian brains, bonding behaviors seem to deliver just the right amount of oxytocin to induce and strengthen attachment—all things being equal. Cuddling registers as rewarding (unless someone has been engaging in too much solo sex). 

In fact, a 5-country study of middle-aged couples found that for men kissing/cuddling was a significant predictor of both sexual satisfaction and relationship happiness. The men valued these activities even more highly than sex. Incidentally, experts think the pleasure of kissing-as-bonding-behavior evolved from the pleasure-producing delivery of chewed food from mother primate to infant before the advent of Gerber's.

Conscious production of oxytocin

Researchers hypothesize that men can keep a distance from temptation by consciously engaging in oxytocin-releasing bonding behaviors with their mates. In the full study, the researchers pointed out that monogamy-promoting oxytocin surges,

may normally depend upon the presence of a close positive relationship in the bond with their female partners and a close physical proximity between them.

In other words, bonding behaviors with one's mate are a good strategy if one wants to effortlessly keep some distance from unknown females.

The ardent researchers next surmised that having sex would be the "most obvious" way to promote natural oxytocin release. This conclusion was no doubt based on the fact that, as lovers begin fooling around oxytocin gradually rises until climax. (Image is from a rat experiment and shows oxytocin rising gradually until ejaculation.)

However, with full integrity, the researchers acknowledged that oxytocin release is not dependent upon climax:

The simple close presence and touch of their partner at any given moment in time might also suffice, (citing a study that showed that "warm touch" decreases stress responses, especially in men).

In short, a whole range of affectionate behaviors (attachment cues) are likely to be effective, just as the researchers somewhat grudgingly acknowledged.

It takes two to tango: oxytocin and dopamine

Oxytocin rises until climaxEnter sex. Oxytocin is high during sexual activity—long before climax. After climax, however, it drops off surprisingly quickly. So does dopamine, the neurochemical behind desire (because prolactin surges and other neurochemical changes inhibit dopamine). As dopamine sags, the urge to merge subsides and your "Miss Right Now" may look more like "Miss Please Disappear." 

This is important information for some lovers, as explained in Will Orgasms Keep You in Love? Block either dopamine or oxytocin and animals don't bond to mates or offspring. Not surprisingly, pair bonders have a higher density of oxytocin receptors in parts of the brain's reward circuitry that release dopamine. Scientists believe this combination explains why pair bonders desire a particular mate.

So, will the drop in oxytocin and dopamine after climax inhibit bonds? Study co-author René Hurlemann thinks not. He privately hypothesized that the bonding effects of oxytocin released during sex with climax may last longer than the brief time that oxytocin blood levels indicate. This is probably true; they may indeed in some men.

But affection and/or sexual behavior without climax has the obvious advantage of not triggering the rapid drop off of oxytocin and dopamine. And it's equally likely that such affection has a lingering positive effect on behavior—and bonds. In fact, we think a sustained oxytocin effect may account for the striking harmony that karezza lovers report in relationships that emphasize frequent, gentle intercourse without the goal of climax.

Moreover, it's possible that repeated neurochemical fallout after climax does not register as soothing to all lovers, or even inhibits their capacity for bonding. Remember the movie When Harry Met Sally? Billy Crystal said that thirty seconds after making love he always wanted to get out of bed and leave. When asked about this, another man said, “Yeah, I guess that is how most men feel. ‘Boom, I’m done! Elvis has left the building. The fat lady has sung. Thank you—and goodbye.’” Not strong evidence of a desire to bond.

This post-coital phase may even leave some men disinterested in their mates yet hungry for other stimulation. A natural neurochemical cycle may be at work, perhaps fluctuating for days in some men (and women), and subtly shifting perception before returning to homeostasis. In short, orgasm is more than a reassuring surge of oxytocin.

Frequency of climax may be an important variable here. Mexican researchers recently showed that if male animals ejaculate before they have recovered from the neurochemical effects of sexual satiety (that is, if they ejaculate too frequently), the result can reproduce drug use-like symptoms and raise anxiety. The males are largely recovered by the fourth day after reaching sexual satiety, but not back to full libido for two weeks.

Bonding 201

Affectionate sex is always delivering benefits but it won't always lead to greater love and bonding. If climax were the key to stronger bonds in humans shouldn't we be seeing more lasting romances than ever now that hooking up is a cultural norm and mutual climaxes readily attainable via natural and synthetic means?

The situation is complex. Intercourse generally entails some activities that are unquestionably evolved bonding behaviors: skin-to-skin contact, nurturing touch, contact with breasts, kissing, and so forth. All can release oxytocin before climax arrives (and whether or not it ever does).

However, peak orgasm itself can carry a mixed neurochemical message. It sends some guys into a neurochemically induced stupor. Many men also crave "cave time" for a while thereafter. Some women are affected too.

Might sustained pair-bonds depend upon initial mating frenzy (supported by temporary, extra-exciting "honeymoon neurochemicals") followed by frequent comforting, flirty contact more than upon frequent climax? Animal biologists point out that in lasting pair bonds much of the contact exchanged is pretty tame: huddling together, mutual grooming, tail-twining, and so forth. Like flirty human behavior, mounting is also a common bonding behavior in paired animals. However, various primates engage frequently in mounting, genital rubbing and even copulation without ejaculation.

Bottom line: If more orgasms with your mate don't soothe your amygdala, strengthen your bond, or help you keep a distance from unknown females, you may wish to increase the frequency of classic bonding behaviors (kissing, cuddling, skin-to-skin contact) and flirty behavior instead.

If you're feeling especially daring, consider combining these tactics with frequent, affectionate intercourse without the goal of climax. Need inspiration to try something so unfamiliar? Here's one man's experiment:

My impetus to finally give Karezza a shot with my girlfriend was another one of my orgasm "benders." I had 11 orgasms in 6 days, and I just felt like crap. I wasn't sleeping. I had that sorta tired, unmotivated, blah feeling. My attitude toward my girlfriend was one of total indifference. So tonight we gave it a shot. It was fantastic, and she loved it, which is a relief to me. We went slow, tried a variety of positions, and just enjoyed ourselves in a very relaxed and sensual way. I was a little surprised at how I was able to keep from orgasming and just find a "zone" where I felt good and not like I was escalating. I sorta went back and forth from this really intense NEED for her, and then settling back down into just enjoying the sensations. I was really surprised to look at the clock and discover we'd been doing it for almost an hour.

Right afterward we went to dinner with a couple friends of ours. In the car on the way, we were so touchy and amorous. We were both just feeling "WOW" about the whole experience. At dinner, I was "on my game": quick witted, charming, focused. My social anxiety and feeling of social awkwardness were very low. I felt confident. We came home and cuddled for another 30 minutes before she had to go home. I showed her the "orgasm v. performance" video and she was very intrigued by it.

This recipe for greater harmony and wellbeing has been around for thousands of years. Recent research about what really bonds mates long-term is helping to explain why this ancient approach to sex may make men happier and more sexually satisfied in lasting relationships.