- Apr 27, 2009
Gay Animals, Social Sex, and a Misunderstanding of Natural and Sexual Selection
At first I was going to comment directly on the article, but couldn't find a place for it.
Then I noticed the article is 3 years old.
Then it occurred to me; that's exactly what my blog is for! Remember? Duh.
On to my comments:
This is a fascinating study and long over due research, which deserves far more attention that it's gotten for both social and scientific reasons.
However, I must partially object to the conclusions of this particular article.
It presents a false dichotomy. None of the observed activities contradict the basic principals of Darwinian evolution, including sexual selection. They may seem to contradict some assumed extensions of the basic mechanisms of evolution, but those assumptions are the things which must be thrown out, not the entire theory.
Sex serves a social function. This is true not only in humans, but in a great many other species as well - generally those that are more complex, intelligent, and social. This much is clear.
This does not mean sex is not also about reproduction. It is not an either/or question. To dispute that sex is primarily about reproduction, the survival of one's genes, is just plain silly.
But simply maximizing number of offspring does not necessarily lead to the greatest number of survivors a few generations down. Increasing the quality of a few offspring, and improving the environment they grow up in can be an alternate and potentially more successful strategy for grandkids (and greatgrandkids, etc). In a social specie where individuals are dependent on the group, any behavior which increases the cohesiveness of the group has an adaptive advantage.
Because something has a primary function doesn't mean other useful things can't be gained in addition.
By the same line which suggests non-reproductive sex is a "waste" of energy or sex cells, one could just as easily see play and all other forms of recreation, reciprocal grooming, and pretty much any activity besides acquiring food and mates as a "waste" of energy as well.
But without the assumption that non-reproductive sex is "wasteful" from a sexual selection stand-point, the entire argument breaks down.
Especially since, in the majority of cases shown, the animals being referred to as gay are actually bi.
If female macaques mate with other females 93% of the time, then they mate with males 7% of the time, which is enough to occasionally get pregnant and have offspring. All-male sheep and giraffe orgies are in addition to mating with females, not instead (even if they are more common). All that is required for the theories of sexual selection to hold is that when individuals do choose to mate with someone of the opposite sex, they choose the sexist partner available, and that what is considered sexy is not always directly adaptive (outside of being sexy) - such as the classic peacock-tail example.
In the last section of the article it is in fact admitted that in all the examples cited of homosexual behavior in the animal kingdom, the activity was in addition to reproductive sex, not instead. And while that fact lead to the (otherwise baseless) claim that heterosexuality (as well as pure homosexuality) in humans is a purely social construct, what few scientific studies have been done on the subject have found quite the opposite to be indicated: in human males at least, possibly no one is bi. Researchers have studied groups of individuals who self-report as gay, straight, and bi, and took direct measurements of physiological response to various images. Turns out guys who claim to be bi actually show a significant (physical) preference for one gender or the other. I wouldn't go so far as to say they are "lying" - attraction goes beyond mere sex and physiology - but as far as what is "natural" and what is "social", there isn't much evidence to support that all humans are inherently bi (interestingly enough, the same type of study finds that women - regardless of self-reporting - tend to respond to both genders). I do know of at least one other specie which, like humans, seems to have individuals who are exclusively gay. Penguins. They share another trait with us as well, one which may be even rarer than homosexuality. Monogamy. And it would follow that these two go together, because if you are faithful to one partner, being bi becomes meaningless.
(A brief aside: As I was writing, Pandora played a song by Queen. The bio caught my eye and I read a little more. Then I took a break to watch a little of them on Youtube. I realize I wasn't around in the 70s to see what the culture and style was like, but I am baffled that it was a secret that Freddi Mercury was gay. I mean come on! Never mind the hair or the leotards - wasn't the name of the band a clue?? But I digress...)
The apparent selfish/altruism conflict disappears when you consider that the unit of evolution is not the specie, not the individual, not even DNA, but the individual gene. From an evolutionary standpoint, altruism can be seen as an individuals estimation of how many genes they have in common with the recipient of their assistance. Any member of the same specie shares 99.5% of their DNA. So while acting selfishly is advantageous (since you share 100% of your genetic code with yourself), as long as the benefit to another slightly outweighs the cost to yourself, altruism can be advantageous from a natural selection standpoint as well. Someone from the same group/pack/heard is likely to have even more genes in common, a close relative even more so, and willingness to sacrifice reflects this (in humans no less than any other social specie).
Overall, the main problem is just that this view of sexuality - much like the one it is hoping to displace - is reductionist and over simplistic. You don't need to force fit the oystercatcher into a simple theory to explain its behavior: a consistent minority of humans are polygynous too, and in those families most are cooperative with both mother's getting along and helping each other. But in some cases personalities conflict, or jealousy is an issue. In humans you wouldn't expect anything different. It would be like calling either happy or dysfunctional (monogamous) marriages an anomaly. They both exist. People are like that. Apparently so are oystercatchers. Neither conflict nor cooperation is the "true" default. Game theory shows many many different combination can be stable. Different things work for different situations, and for different individuals. Claiming that conflict is an anomaly, as often as it occurs, presents the exact same problem as calling homosexuality an anomaly does. It may not be the norm, but it isn't rare either, and if a theory has to explain it away, the theory is more likely to be flawed than reality. Reality is never flawed. Reality just is. It isn't debatable.
I tried that once. I found a cactus in the middle of a deciduous forest in the mountains on a lonely road in southern Mexico. I told it that cacti should live in desert. I told it plainly and simply, as a statement of fact. I told it more firmly: cacti don't grow in the mountains. I yelled at it. I got upset, and flung rocks and sticks in its general direction (mind you, I had been bicycling, solo, in a country where I didn't speak the language, for weeks at that point, I had been climbing the same mountain for days, and was many miles from civilization). And after all my pronouncements of science, for all my certainty, the cactus was still there. It's probably there now, on that mountain in between Taxco and Mexico City, among the pine trees.
Whenever the theory diverges from actual reality, reality wins. That was one of the points of the article, but then it tries to do the same thing with human behavior and intra-species conflict. In the end it does seem to stray from pure science to trying to push a particular socio/political agenda, which is unfortunate because the information, presented without bias, really is important for its implications for human society, the idea that sex for pleasure is perfectly natural, normal, and acceptable, in all of its various forms.
Sexual selection does not preclude homosexuality, and indeed it can even have an adaptive advantage due to its encouragement of social cohesiveness, so well demonstrated by our closest evolutionary relatives, the bonobos. This would still not explain masturbation, which is also easy to find in the animal kingdom. It has neither a reproductive nor a social function.
But evolution doesn't work like engineering. There is no plan set out in advance. Its just a bunch of stuff that happens, and some of it works.
One thing that works is flexible complex decision making systems (brains) because they can deal with a greater variety of situations than instinct alone can. With free will an individual can prioritize themselves - not their genes - but genes keep our goals in line with theirs by controlling what feels good. Things which tend to promote more surviving copies of genes feel good, from eating food to caring for babies to generosity. But its a pretty imperfect system. Sugar is a good energy source, but we took advantage of sugar tasting sweet to create things like chocolate cake and Twinkies - even diet soda which has exactly zero nutritive value, but triggers the sensory system in the same way as fruit. We can experience parenthood through adoption. We get the thrill of the hunt via sports and games. None of these increases our chances of having genes survive. But they are all byproducts of something which does help us survive - a level of intelligence that allows us to create and use technology. Sometimes an adaption has more than one effect, and one of them is extremely useful. As long as the other effect isn't destructive, the overall adaptation will be selected for. Because of that we can safely short-circuit our own pleasure responses with movies and drugs and masturbation and still be fruitful and multiply. The cost of these pointless activities is negligible. There doesn't have to be a "why". It feels good. The question in this case is actually "why not?"
It shouldn't make one bit of difference what is "natural" and what isn't. Natural isn't always good. Getting eaten by a mountain lion is natural. However, as it turns out all the various "perversions" do happen to be perfectly natural. So, whatever you are into, stop worrying about it, and enjoy.