Clownfish have an extremely unusual take on sex. Members of some species start as undifferentiated and sexually inactive males, with only the largest of them being the sexually active male. The female is simply the largest, and if she dies, the male grows larger and takes her place. If two male clownfish are paired together, the larger of the two will establish dominance and become the female. This sex change takes a few months, with behavioral changes occurring sooner.
All this brings to mind the question — are clownfish optimally sized? What is socially optimal — the procreation of the species as a whole — may differ from what is individually optimal. Being bigger might be advantageous for the individual, because they can breed, but disadvantageous for the species, which would procreate better if everyone were a bit smaller.
Clownfish do not literally choose their size, of course. We can still regard them as effectively choosing their size. Armen Alchian has an interesting 1950 paper, “Uncertainty, Evolution, and Economic Theory”, in which he tries to reconcile rationality with people not seeming to use rationality to guide their decisions at all. People explicitly making decisions “rationally” is not necessary for rationality to describe the behavior of firms and humans. All that is needed is for people who do behave in the maximizing way (even if by accident) outcompete those who don’t. Rationality aligns with evolutionary success.
We cannot assume, however, that rationality means optimum. There are lots of ways in which locally maximizing decisions lead to outcomes which diverge from optimum. People can both defect in a prisoner’s dilemma, for example. Sexually selected traits need not make the species as a whole successful. What may have started, like the absurd feathers of the peacock, as a credible signal of fitness, becomes a positive burden on a species as a whole. If they could but cheaply determine the quality of mates, there would be many more clownfish and peafowl in this world.
Can we see animals in the same light as we do humans? In some sense, they have as much claim to be making decisions as humans do. They are atoms too. We do not exist independent of the universe. We “choose” to act in the same way a deer chooses to act, or a rock does. Just as we have a preference to consume food and burn calories, so too does a fire have a preference to consume fuel and burn wood.
But in another sense, we are able to organize in a way above animals. Thinking and consciousness, to my mind, are the ability to overcome collective action problems and cooperate. We can foresee how the game will play out, if we take the path which is a local maximum, and avoid it when that is bad. That is what being human is.