Feb 14 2012

Love is in the Brain

As you cuddle with your mate your brain receives a comforting surge of oxytocin, reinforcing your feelings of attachment. More intimacy gives your pleasure centers a shot of dopamine, strongly reinforcing the behavior. Your brain becomes increasingly bathed in dopamine, serotonin, and other hormones and  neurotransmitters, resulting in a suite of physiological and behavioral responses evolved to maximize the probability of inserting your genes into the next generation.

In the afterglow of your subconsciously Darwinian act, you contemplate what attracted you to your mate in the first place. If you are male then you probably responded positively to a certain waist to hip ratio indicating good birthing potential. Full lips and facial features with a rosy tone to the skin also indicates youth and health – other good predictors of of breeding success.  Females are also attracted to signs of health and vigor, but also dominance and power (however this specifically manifests in your culture).

Evolutionary changes to your brain’s hardwiring and chemistry have spared you the tedious task of performing a biological assessment of potential mates. Rather, you just have an automatic feeling – an attraction – that is largely based upon a cold subconscious calculus of breeding and life success. You find yourself thinking obsessively about a good mating prospect. You may feel giddy just by being in their presence. The mere sight of them gives you a pleasurable spike of dopamine.

This crazy chemical in love phase will last about 9 months (for most people – the occasional “swan” may last much longer), long enough for longer term attachment mechanisms to take effect. This is also long enough for there to be a high probability of bringing children into the mix, forming other (perhaps even more powerful) chemical attachments.

A host of biological and neurochemical changes have occurred in human evolutionary history to make us a pair-bonding species (mostly). Females no longer advertise their fertility with visible estrus, for example. Males invest heavily in their children, and have formed strong feelings of jealousy to help ensure that their mate’s children are indeed their own as well. Females trade faithfulness and perpetual receptiveness for a promise of male protection and providing for them and their children, and seem to wield a variety of psychological talents for manipulating their stronger partners into staying invested themselves.

At least, this all is the current neurbiological and evolutionary psychology explanation for romantic love. Much of it is based on at least reasonable evidence. The role of dopamine and oxytocin are fairly well described in animals, but human studies are still preliminary and it is not yet definitively proven that the animal data can be extrapolated to humans. The evolutionary psych explanations are reasonable but hard to prove, and likely filtered through cultural norms.

There is also a great deal of natural variability in human behavior related to romance and sex. The most obvious variable is gender attraction, but there are also variations in what people find attractive, as well as interest in sex. Some people have “fetishes” – specific things or situations that trigger an erotic response. It’s not clear why this happens – a quirk of brain development or just life experience.

The scientific view of love and romance can seem anything but romantic, and we can’t even let you have the scientific explanation without pointing out our current uncertainty and the need for more research. The fact is – love and romance are biological/neurological phenomena. They are being studied and we are slowly building a reductionist picture of exactly how and why we feel and act the way we do.

This view, however, is not incompatible with romance. It is a rationalist romantic view. Understanding biology is not inconsistent with embracing and even reveling in the human condition. Feelings of love and attraction are not diminished at all by an understanding of the possible evolutionary advantages of those feelings, or the underlying brain chemistry, any more than they are enhanced by ascribing those feeling to fate or magic.

Understanding the biology of love, rather, can be empowering.  Sometimes we make decisions that are not in our best interest because we are in the grip of neurotransmitters and evolutionary signals of which we are not consciously aware. Thinking that those feelings are due to some magical design of the universe or something akin to fate, or to forces outside of your control, are convenient justifications for giving in to feelings that may be leading you to bad decisions. It’s helpful to understand that evolution does not need you to be happy, just prolific. You, however, may prefer to be happy, and therefore may wish to make more reasoned decisions. It’s also helpful to understand the power of neurochemistry, and therefore perhaps it’s not a good idea to make rash decisions when you are in the grip of “romantic psychosis.”

A scientific understanding of our own brains does not lessen the feelings of love and attraction, but may help us to enjoy and embrace those feelings without being ruled by them.

Happy Valentines Day.

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35 responses so far

35 Responses to “Love is in the Brain”

  1. Nikolaon 14 Feb 2012 at 10:09 am

    A first class post, on any date.
    Thank you!

  2. Jim Shaveron 14 Feb 2012 at 10:30 am

    Steve, I hope you don’t mind if I write that on a big, red, heart-shaped card for my wife today. I hope she likes it! :)

  3. ccbowerson 14 Feb 2012 at 11:43 am

    I don’t understand the belief that people often have: that something important is lost when we learn or gain some understanding about certain topics. I would argue that what was lost was not important at all, and what is gained only adds to our experiences. Just as becoming a dietician does not make food less delicious, nor does being an OB/GYN make one’s own child’s birth less important. Learning that we are what our brains think and feel do not diminish what is it to be human, it makes our understanding more accurate and profound.

  4. BrainFromArouson 14 Feb 2012 at 12:19 pm

    Steve, you big softie. :)

  5. locutusbrgon 14 Feb 2012 at 1:40 pm

    Nothing quite like getting home from work, slowly opening that Pizza box, and getting the shot of Dopamine. Ahh True love.

  6. Kobraon 14 Feb 2012 at 2:04 pm

    “ccbowers:
    learn or gain some understanding about certain topics. I would argue that what was lost was not important at all, and what is gained only adds to our experiences”

    Most people see love as something mysterious and infinite, detached from anything material, including neurochemistry. Rather unfortunate, but to each their own.

    I’m curious to know if we regard ‘love’ as nothing more than a form of ‘obsession’ at its weaker levels. I mean, Dr. N writes that we have our obsessive thoughts when desiring a reproductive mate, but when someone then ‘falls in love,’ do we regard that as a form of obsession, especially in the ‘honeymoon’ stage? Clearly we can also see it manifested when someone breaks up with their partner, so there must be a subconscious component of obsession. Can attachment be considered obsession as well?

    This is all assuming that the word obsession has some flexibility in its definition.

  7. colluvialon 14 Feb 2012 at 5:47 pm

    “This view, however, is not incompatible with romance. It is a rationalist romantic view. Understanding biology is not inconsistent with embracing and even reveling in the human condition.”

    Many people think that a scientific explanation diminishes the value of these emotional experiences because they wrongly assume it means there’s an ulterior motive – sort of a scheming little homunculous pulling our strings. Considering that there’s nothing to contain the homunculous or the motives, we’re just left with a set of behaviors. The fact that they have any evolutionary purpose at all is the result of those behaviors, not a cause of them. We, and our ancestors, behave as we do because otherwise we probably wouldn’t be here.

  8. Kobraon 14 Feb 2012 at 6:38 pm

    Crap, just realized I misquoted the wrong part of cc’s reply: “I don’t understand the belief that people often have: that something important is lost when we learn or gain some understanding about certain topics.”

  9. willradikon 14 Feb 2012 at 8:17 pm

    That’s not where I’m putting the love. I don’t think she’d appreciate that.

  10. willradikon 14 Feb 2012 at 8:35 pm

    Steve, I agree (I’m no expert, just a hunch based on cultural observation.) they’ll definitely find in the future that attraction, especially as related to gender, is probably a lot more complicated and heavily tied in with however the brain builds cultural associations. I find references to dominance and power–very pervasive in our culture, still–as driving women’s attraction to males to be a little trite. Sure, there are a lot of women out there who go for the “alpha male” types, but based on my personal experience, (anecdotal evidence, I know. : >) I would say this is probably wildly overrated by American society, which, on the average, harbors a startlingly atavistic viewpoint of gender roles: what comprises them and how important they are. This stuff is fascinating.

  11. neilgrahamon 15 Feb 2012 at 12:13 am

    Are we talking about Eros, Philia, Agape, or, perhaps, Caritas?

  12. BillyJoe7on 15 Feb 2012 at 5:21 am

    “Some people have “fetishes” – specific things or situations that trigger an erotic response. It’s not clear why this happens – a quirk of brain development or just life experience.”

    My feeling is that it must be a brain quirk.
    But I have only anecdotal evidence which is, of course, unreliable.
    My fetish is skin – as in skin moles and blemishes. I can remember being completely obsessed by a girl with widespread eczema; and another who, I learned later, suffered from a mild form of the condition called icthyosis. Alas my obsession was not reciprocated in either case and I ended up marrying a girl with boringly flawless skin. :)

  13. nybgruson 15 Feb 2012 at 9:27 am

    To follow up with Dr. Novella’s point at the end (as well as CCBowers), one of my favorite quotes of all time from one of my favorite people of all time:

    “Science is not only compatible with spirituality; it is a profound source of spirituality. When we recognize our place in an immensity of light‐years and in the passage of ages, when we grasp the intricacy, beauty, and subtlety of life, then that soaring feeling, that sense of elation and humility combined, is surely spiritual. So are our emotions in the presence of great art or music or literature, or acts of exemplary selfless courage such as those of Mohandas Gandhi or Martin Luther King, Jr. The notion that science and spirituality are somehow mutually exclusive does a disservice to both.”

    -Carl Sagan

  14. BillyJoe7on 15 Feb 2012 at 2:59 pm

    nybgrus,

    I think if he was alive today, Sagan would have avoided using the word “spirituality”. It is often misconstrued by those with an axe to grind. Einstein often used the words “god”, “religious” and “spiritual” and eventually had to fight off the misinterpretations that others put on those words.

  15. cwfongon 15 Feb 2012 at 3:29 pm

    How would you avoid the use of the word in an article that is precisely about its use?

  16. nybgruson 15 Feb 2012 at 8:18 pm

    @billyjoe:

    I agree. It grinds on me endlessly as well. However, I think I agree with cwfong – running from the use of words is like acquiescing to terrorist demands.

    I think I would like to demonstrate why I am indeed spiritual and continually enraptured by the world and universe around me… without any god or religion, thank you kindly.

    I would like to let people know how much more wonderous the world is through my eyes when I look at a flower opening and think of the interplay of light producing energy and moving microfilaments. Or when I went to Las Vegas last year for the first time since the Aria was built and saw the majestic building and was impressed by its beauty…. and then blown away again thinking about the structural engineering that needed to be done to create a building with a lean like that and not fall over!

    I love being overwhelmed by the elegant interplay of all the forces and particles around me that make up the universe. And I pity those that think “reductionist” is an evil term because they are more content to just sit and stare at it, with no better answer than “I don’t have a clue how that actually happens” and think that is spirituality.

    No sir, I agree with Sagan.

  17. BillyJoe7on 15 Feb 2012 at 10:28 pm

    Steven Novella seems to have been able to write a whole article about love without mentioning that word once.

    I suppose you could use the word “spiritual” as a secular exaptation of the original religious meaning which implied something non physical.
    I prefer to avoid it for the very reason that it is often mistaken for that relgious meaning.
    Each to his own I guess.

  18. cwfongon 15 Feb 2012 at 10:48 pm

    The word comes from spirit, which comes from the Latin: spiritus ‘breath, spirit,’ from spirare ‘breathe.’

  19. BillyJoe7on 16 Feb 2012 at 4:53 am

    …as in breathing the life force into the physical body.

  20. BillyJoe7on 16 Feb 2012 at 4:56 am

    BillyJoe: “Steven Novella seems to have been able to write a whole article about love without mentioning that word once.”
    Steven Novella at SBM today: “Essentially – a few wealthy and woo-friendly donors trying to promote their spiritual world-view”

    Hmmm…I think I may have a collaborator. :)

  21. ccbowerson 16 Feb 2012 at 9:08 am

    “However, I think I agree with cwfong – running from the use of words is like acquiescing to terrorist demands. ”

    Not sure that I agree here. Choice of words is important if one wants to be understood, and intentionally using a word in a way that is different than most people’s understanding of the word (or its understood definition) opens one to being misunderstood. Spirituality has the word “spirit” in it, and to me implies a belief in a reality outside of the material world. Since I do not subscribe to such a belief, I don’t use the word. I realize that people have used the term in a more broad sense, such as in your quote, but I think this approach has problems. First, it is confusing since it is likely to be misunderstood, but in addition the broad use of the term seems so vague that it approaches meaninglessness. That is unless someone has a reasonably precise definition that I am unaware of.

  22. nybgruson 16 Feb 2012 at 9:46 am

    I don’t think that Dr. Novella’s article needed to deal with spirituality, so his choice to eschew it is fine. He could have included it, if he desired, but he didn’t intentionally avoid the word while writing on the topic (and as you pointed out, used it in the other sense).

    And cwfong beat me to it – it does indeed have its roots in physical terms. Once again, as Sagan said:

    “It comes from the Latin word ‘to breathe’. What we breathe is air, which is certainly matter, however thin. Despite usage to the contrary, there is no necessary implication in the word ‘spirituality’ that we are talking about anything other than matter (including the realm of matter of which the brain is made) or anything outside the realm of science…Science is not only compatible with spirituality; it is a profound source of spirituality”

    CCBowers makes a very good point. When speaking to masses and trying to get your point across, it is important not to use words that are ambigious or could imply the exact opposite of what you mean (à la the way Einstein is being abused by religious apologists). So I fully agree that there is a danger in using the word “spiritual” since the co-opted meaning has become one of ephemeral spirits and magic.

    My only point was that I like the word in its original sense, the way Sagan uses it. I think that it is a shame for us as skeptics and scientists to lose the use of that word because a bunch of theists think it only means magic and ghosts. I think it perfectly captures the profound sense of awe that I personally feel when confronted with those pristine moments of observing the natural world around me (or even reading a great scientific article and learning something profound and new). The thing is that it is the same feeling I would imagine a theist feels when he or she is struck by the profound beauty of the his or her surroundings. The only difference is that the theist ascribes it to a god, and I ascribe it to the elegant natural order of the universe. I genuinely think it is the same feeling and I like being able to describe it as such.

    As CCBowers points out it is a vague term. But the feeling I am trying to describe is itself vague. If you look at the dictionary definitions you find that the number one entry for “spiritual” is:

    : of, relating to, consisting of, or affecting the spirit : incorporeal

    I actually have no problem with that definition, except that the definition of spirit is less satisfactory for me. You have to go to the 4th listed definition in order to get at what I want to convery:

    the immaterial intelligent or sentient part of a person

    If you go with those two definitions, I think it adequately and accurately describes what is going on. Sadly, too much “vital force” mumbo jumbo is mixed in there and the colloquial use is more in line with that than the use Sagan espouses.

    However, I would like to point out that indeed while Einstein’s words of a “god” were wholly misconstrued and used (poorly) by theistic apologists, I have actually never once come across an incidence of an apologist using Sagan’s words on spirituality. I guess we just have to be careful to make our overall feelings on the matter well known (as Sagan did) and always use the word in a context that is unambiguous, so quote miners will have extremely little to work with after you are dead. Perhaps that is why I pretty much always reference Sagan when I speak of spirituality, so that his clear meaning will be always attached to my discussion of the matter.

  23. Steven Novellaon 16 Feb 2012 at 10:05 am

    will -yes, that summary is trite, and I specifically pointed out that evo pscyh explanations are “filtered through cultural norms.” The full story is certainly much more complicated. For example, while there is a lot of evidence that women are generally attracted to traits that are associated with alpha maleness, there is also evidence that alternate strategies for attracting mates exist. There is no one path to reproductive success. There are also many, even conflicting, impulses, and no one factor is definitive.

    The point was simply to give an example of how our sexual attraction is not accidental but is part of how evolutionary forces have shaped our brain function, and that how we feel is the result of subconscious evolved calculations to maximize reproductive success.

  24. tmac57on 16 Feb 2012 at 10:39 am

    I love this discussion! In the spirit of this debate, is there a ghost of a chance that both sides can come to an agreement…god only knows.

  25. SARAon 16 Feb 2012 at 10:56 am

    “Feelings of love and attraction are not diminished at all by an understanding of the possible evolutionary advantages of those feelings, or the underlying brain chemistry, any more then they are enhanced by ascribing those feeling to fate or magic.”

    I’m curious if there is any evidence that this is true, generally speaking about any scientific explanation of a more emotional or spiritual concept. I’ve experienced it both ways.

    For example – I once had a rather stupid romantic involvement, fully aware that I was feeling things that were chemical and not rational – and knowing it didn’t stop the feeling or diminish it in any way or stop me from doing stupid things.
    But, I also remember the feelings of euphoria I had as a teenager when I was particularly moved by singing in a church service – feelings that were enhanced because of my belief that God was in the room. I can’t imagine that I would have those same feelings today at the beautiful music, because I don’t think God is part of the scenario. I would enjoy the music, but probably not have that euphoric feeling. (of course, I can’t recreate that moment to test the my intuition on this subject)

  26. ccbowerson 16 Feb 2012 at 12:11 pm

    nybgrus-

    I don’t disagree with what you are saying (actually I agree with most of it) except that you seemed to place too much emphasis on the distant origins of the word… to me that is approaching the “genetic fallacy.” Current meaning and understanding are much more relevant, unless we are talking about the term in a historical sense. Perhaps I am reacting somewhat to a podcast I heard fairly recently, in which the guest was arguing that we should ‘take back’ the term spiritual. The problem is that its been contaminated (not just by the religious, but also new agers) and I don’t want it anymore=(

  27. cwfongon 16 Feb 2012 at 3:00 pm

    Extramundane, anyone?

  28. tmac57on 16 Feb 2012 at 3:21 pm

    “Extramundane, anyone?”
    No thanks,I just had a peanut butter and banana sandwich.

  29. cwfongon 16 Feb 2012 at 3:40 pm

    I’d rather partake of some well aged spirits about now.

  30. ccbowerson 16 Feb 2012 at 5:01 pm

    I’ll take some of that mundane. Sounds good to me. No spirits for me, but I’ll have an oatmeal stout later.

  31. aesopslyreon 17 Feb 2012 at 8:38 am

    I take exception to one of your assertions RE the mechanisms of sexual attraction. You posited “a rosy tone to the skin” as being an example of a female characteristic which is sexually attractive to males. I presume this article was intended to posit sexual attractors that are universal to Homo Sapiens. Surely you are cognizant that the trait in question would be largely limited to only one subset of human diversity, I.E. Caucasians of northern European extraction. Would you care to revise this statement? Perhaps “clear, unblemished complexion” or the like would be more illustrative.

  32. Steven Novellaon 17 Feb 2012 at 11:20 am

    The fact that only a subset of people have a skin tone that allows for the perception of flushing as a sign of health is noted, but not relevant to the point.

    I was not giving a systematic discussion of visual sexual attraction, just citing some examples. And I pointed out there is variability and cultural filters.

  33. nybgruson 17 Feb 2012 at 12:47 pm

    @ccbowers:

    Yes, I see your point. I guess I just still like the word. Partly for my own self, but partly because it allows me (in a genuine way) to stick it to anyone coming my way who says I am missing out on “something” in life because I am such an “evil reductionist” or atheist. This has happened – and it is a common rhetoric that myself and those like me must lack some qualia of life because we lack…. “spirituality.” To rebut that, I make the arguments I have been making so far.

  34. BillyJoe7on 17 Feb 2012 at 3:03 pm

    aesopslyre,

    “Would you care to revise this statement? Perhaps “clear, unblemished complexion” or the like would be more illustrative”

    You forgot about my fetish.

  35. charmedquarkon 17 Feb 2012 at 3:54 pm

    Another wonderful post Dr. Novella!

    I abelieve the more we know about something the more we can appreciatte and maximize its benefits. Our universe is certainly more fascinating with what we have learned through quantum mechanics, astronmy etc… in the past three decades.

    In addition to dopamine and oxytocin, the neuropeptide argenine vasopressin plays a crucial role in love.

    See some of the fascinating experiments comparing prarie voles to mountain voles. By increasing mountain voles exposure to oxytocin and vasopressin, the promiscous mountain voles joined the mating habits of their pair bonding cousins the prarie voles.

    Patricia Churchland’s recent book, Braintrust, does a nice job of addressing this topic.

    Humans are a part of the small percentage of mammals ,3 to 5%, that engage in pair bonding. As very social creatures, in addition to our neurochemistry, culture certainly plays a large role in our intimate relationships.

    Happy belated Valentine’s Day fka Lupercalia!

    (as with most well known current holidays, the mythology and, history and true origin of this holiday are quite interesting)

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