Some Concluding Evolutionary Mysteries

I’ve said it before and I’ll say it again: Those of us engaged in teaching, writing and speaking about science are participating in a Great Deception – well-intended, to be sure, but a deception nonetheless. The gist of that deception is that we teach science as a list of established findings rather than what it really is: The world’s best and most rewarding process of “finding.” Students and the general public are for the most part receptive to learning about science, but all too often, this means learning what we place before them, consuming our discoveries, then waiting for the next course.

The reality, on the other hand, is that it’s the kitchen, not the dining room, where the exciting stuff happens. More to my point, it’s in the imagination of the chefs, those who try new combinations and invent new recipes.

Enough with the culinary metaphor. My point is that there is a whole lot more to the science that we don’t know—the mysteries yet to be solved—than a catalog of what we do know. Here is a short list of just a few human evolutionary mysteries, puzzles of human nature that are as yet unsolved. In each case, numerous hypotheses have been proposed; “final answers” aren’t yet in. But that’s OK – in fact, its more than OK: “There’s a crack in everything,” writes Leonard Cohen, “that’s how the light gets in.”

Homosexuality. Why does it persist, given that same-sex preference results in lower individual fitness?

Hypotheses: – Homosexuals ultimately enhance the fitness of gay-preference genes by contributing positively to the success of those genes, in relatives other than their own children (“kin selection”).

-       Gay genes contribute to their own success when present in the bodies of opposite-sex relatives, so-called “sexually antagonisic selection.” The idea here is that genes predisposing to, say, gayness in males (lower genetic fitness) also result in higher fitness when present in females.

-       Homosexuality diminishes within-group competition and/or increases altruism, coordination, and sharing, thereby selecting for homosexuality at the group level.

-       Homosexuality is a strategy for those who for whatever reasons would be less successful in heterosexual competition.

-       It’s a nonadaptive or even maladaptive consequence of hormonal, genetic, and/or experiential circumstance.

-       It’s just a manifestation—one of many—of nature’s “exuberance.”

-       It’ a way of cementing social relationships, enhancing “reciprocal altruism.”

-       It’s a consequence of some as-yet-unidentified heterosis (like sickle-cell disease).

-       It correlates with greater verbal, social, and artistic skills, with consequent reproductive advantages, if not for the individuals then for their relatives and or larger social unit.

-       It may be socially imposed upon certain individuals, analogous to the phenomenon of “reproductive skew” in other animals.

Art. Defined broadly to include music, visual art, poetry, literature, dance, sculpture, etc: Why is it – in some form or another – a cross-cultural universal?

Hypotheses: -  Maybe it’s a nonadaptive byproduct of our exceptionally large brains that have been selected for other reasons; i.e., “cheesecake for the mind.”

-       A different incidental result of our large brains, this time because we have evolved neural capacities for perceiving and appreciating more than is needed simply to maximize our fitness? Spandrels?

-       Practice? Play? Social coordination? An opportunity to run through various scenarios in one’s head rather than in real life?

-       A means of displaying internal social cohesion, for internal and/or external consumption?

-       A sexual display, on the part of consumers no less than art’s creators?

-       The equivalent of social grooming among nonhuman primates?

Religion. Given that religion, in some form, is another cross-cultural universal – and something that typically demands sacrifice without obvious compensations -  what explains its adaptive value?

Hypotheses: – Genes “for” religion? (But if so, what’s their selective payoff?)

-       A parasitic or viral meme?

-       The result of a Hyperactive Agency Detection Device?

-       An extension of the clearly adaptive human capacity to entertain what psychologists call a Theory of Mind?

-       An unadaptive consequence of having large brains—selected for other reasons—that induce us to wonder about things like death, purpose, etc. (thus, a similar hypothesis to one advanced for the evolution of art)?

-       Spurious attribution of causes to “explain” any effects (analogous to placebo)?

-       Juvenile vulnerability to adult teaching?

-       Saves people from the pain of having to think for themselves (Dostoyevsky’s “Grand Inquisitor” phenomenon, aka “choice overload”)?

-       A holdover from our eons as nonhuman primates, gaining security by following a dominant individual: God as alpha male?

-       Mimics the addictive effects of other ritualized activities?

-       Generates group coordination and cooperation, a kind of “social glue,” especially during war?

-       Helps subordinate selfish, individual goals to that of the larger group?

-       Helps generate reliable social norms and morals among participants?

-       Occasionally generates powerful “last gasp” efforts when non-believers might give up?

Consciousness. It isn’t difficult to imagine “humans” who function very effectively in the biological world, but are essentially unconscious zombies; given the anatomic and physiologic cost of big brains, why are we conscious?

Hypotheses:- A nonadaptive byproduct of having evolved large brains for other, adaptive reasons.

-       The payoff of being able to play “trial and error” in one’s head instead of in the much more dangerous real world?

-       The payoff of being able to restrain one’s “natural” inclinations, or force oneself to do something that doesn’t come “naturally.”

-       A tactic that results from the human awareness of mortality, which in turn induces (at least some) people to reproduce, as a response?

-       A consequence of our convoluted social lives, which selects for the ability to imagine how others might perceive us, all the better to manipulate them?

Among some of the other evolutionary mysteries, which I’ve already described briefly in prior posts, are a number associated with women’s sexuality: Why do women experience orgasm? Why do they menstruate, have pronounced nonlactating breasts, conceal their ovulation, undergo menopause? Why do men have shorter lifespans? Why do we blush, laugh, sleep, dream? Why did we evolve such large brains, and so quickly? Did we evolve from one phylogenetic line or many?

Unlike Sisyphus, who was condemned to spend eternity pushing a huge rock up a steep hill only to have it roll back down again, the scientific push for greater knowledge doesn’t slip backward (at least, not for long) – although it never reaches a safe, secure, tedious and satisfactory stopping point. There are always more hills to climb, more mysteries to identify and then to solve.

It might also help to recall a different parable, in which two brothers are told to dig for treasure in the family vineyard. They found neither gold nor silver, but their labors greatly enriched the soil.

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