Friday, July 28, 2017
Logically Moral Animals
I was called on a point recently by a colleague. He accused me of jumping between two irreconcilable positions. One the one hand, I argued that human beings are distinct from other animals in kind and not merely in degree (i.e., just more intelligent). On the other hand, I argued that traces of human intelligence and moral capacity are found in animals. I replied that I’m a primate; jumping from one tree to another is what I do. It got a laugh.
I don’t think I was actually guilty of a contradiction. Traces of language are indeed found in animals. A certain call may indicate food or danger. Yet, so far as we know, no other animal is capable of drawing and recognizing a simple symbol like a stick man. Differences in kind do not require altogether novel capacities. They require that something about the way a capacity is exercised be novel.
Today I have been looking at two studies of logically moral behavior among non-human animals. Vampire bats have long served as poster children for reciprocal altruism. These winged mammals feed exclusively on blood. They need to feed about once every three days. This presents a challenge as their food sources have legs and can move in unpredictable ways.
The vampires deal with this problem by blood sharing. A bat who returns hungry can count on a share of a meal from a luckier roost mate. This is an insurance policy; however, it invites cheating. An unscrupulous bat might take from others and then refused to share. If he gets away with that, his offspring will proliferate and the sharing system will collapse.
That requires an enforcement mechanism. Vampires remember. If bat X refuses to share with me today, I will refuse to share with bat X tomorrow. Cheaters can be systematically eliminated from the gene pool.
I doubt that bats are consciously moral. I am sure that this sharing system is logically moral. Bat X either fulfills his obligations or does not. If so, he benefits from the social contract. If not, then he is excluded from the contract.
I used this example in the paper I am writing for the APSA this year. I wanted to be sure that recent scholarship backed up this account, and it does. Gerald G. Carter and Gerald S. Wilkinson have a piece in the Proceedings of the Royal Society (2013). They teased apart alternative explanations for the vampire’s behavior.
Are the bats sharing only because they are related to one another? If so, then kin selection and not reciprocal altruism would explain their behavior. In the experiment, relatedness was the least reliable predictor of one bat’s willingness to share with another.
Perhaps sharing was a response to allogrooming. Bats share with cuddle buddies. Perhaps it was influenced by mating agendas: if I share with her, she will mate with me. Those were the third and second-best predictors of sharing behavior.
The best predictor was simply that the other bat had shared in the past. That looks like reciprocal altruism. Sharing is rewarded with sharing. Remembering who is a good partner amounts to the construction of a social network.
The most interesting thing to come out of this study is this: sharing was often initiated not by the hungry bat but by the sated bat. Why would this be so? Sharing builds a network of obligations. If I can get you to accept my donation, you are now obligated to me. This system is, as the sociologists say, socially constructed. It depends on reputation, what the other bats think about this one.
Something of the same kind is going on in a study of cleaner fish. These fish make their living eating parasites in the jaws, gills, etc., of larger predators. As in the case of the vampire bats, this arrangement involves mutual obligations and the temptation to cheat. Client predators can cheat by gobbling up the cleaner after the work is finished. That is policed by a simple accounting. A predator who behaves that way will discover that the cleaners no longer come out of their cleaner stations when he swims in for a touch up.
Cleaner fish are also tempted to cheat. The parasites they feed on are not quite as attractive as the mucus in the client’s jaws. What encourages the cleaner to confine itself to the parasites? Russel D. Fernald explains this in his note Animal Cooperation: Keeping a Clean(ing) Reputation [Current Biology Vol. 21 No 13].
It turns out that cleaner wrasses are more likely to keep honest (parasites only) when they are observed by a number of potential client fish. They seem to value their reputation in the business. It seems very unlikely that these fish, with their tiny brains, have any conscious awareness of the stakes. It doesn’t matter. Natural selection has made the logically moral choices for them.
Again, the reciprocal arrangement is socially constructed. The fish do not need to understand the system, but they do need to notice who is watching.
The old dichotomy between nature and nurture, biological influence and social construction, is long out of date. Temperature, saltiness, water and nutrients are factors that exert selection pressure on organisms. Social arrangements and the likes and dislikes of individual interactors for one another also exert select pressure.
Choice is a powerful influence on the evolution of pretty much everything. Another powerful influence is moral logic. Plato was right, at least about the world of living organisms. The most important idea is the idea of the good.