Monday, February 15, 2016

Altruism and Evolution (February 14, 2016)

This week the week of Darwin’s birthday, we join congregations around the world in talking about the Theory of Evolution, because it helps us understand how we, and every other species with which we share this earth, came to be. We take time to talk about evolution because, despite the fact that it is backed up with centuries of verifiable scientific research, evolution is under increasing attack in our schools and in our public discourse. We also celebrate evolution Sunday because the science of our physical reality is not just for “experts” with advanced degrees -- the story of your body, your eco-system is a story every one of us should know in order to understand ourselves and the world in which we live. That’s why we list as one of our sources: “Humanist teachings which counsel us to heed the guidance of reason and the results of science.”

Today is also Valentine’s Day, so I wanted to tell you a love story. Not a story of romantic love, but the love of other living beings that binds us to one another. I know Vampire bats don’t seem that romantic on the surface, but the precious gift they give one another is eminently more practical, and more precious than a heart shaped box of chocolates. These creatures out of our nightmares, who suck the blood of large mammals, such as cattle, are actually one of the most selfless animals we know of. Researcher Jerry Wilkinson, chair of biology at the University of Maryland-College Park, discovered in 1977 that if a bat is not able to find food, say because of illness or lack of large mammals or because a researcher has put her in a cage, that other bats in her group will share their dinner with her by regurgitating into her mouth. [i] So, just like humans, bats can choose to give their own food to help another hungry being.

Bats are not alone in their altruism. The Vervet monkeys cry out to warn their neighbors of a predator, even though they increase their own personal risk by revealing their position with that cry. [ii] There are even stories of altruism in Bacteria, like our nemesis e coli. Scientists have found examples of special drug-resistant bacteria sharing something called “indole” (\ˈin-ˌdōl\ ) with its neighboring bacteria who aren’t drug resistant and so can’t produce Indole on their own. ( Indole is the compound that helps bacteria fight off antibiotics). These altruistic super-bacteria share even though it weakens their own reproductive capacity when they give away this precious resource. [iii]

The Vampire Bat, the Vervet Monkey, the e coli bacteria are all engaged in Altruism. When we talk about human altruism we use the term pretty loosely, to mean anything from pulling a fellow subway rider off the track in front of an oncoming train, to bring a put of soup to a neighbor who has the flu. But in evolutionary biology, there is a very precise definition. “An organism is said to behave altruistically when its behavior benefits other organisms, at a cost to itself. The costs and benefits are measured in terms of reproductive fitness, or expected number of offspring. So by behaving altruistically, an organism reduces the number of offspring it is likely to produce itself, but boosts the number that other organisms are likely to produce.”[iv]

Since the earliest days of our thinking about evolution, altruism has stumped scientists. If what propels evolution is the competition for limited resources, altruism seems to throw a monkey wrench into the theory. Even Darwin was troubled by this. About 13 years after he first published “ON the Origin of Species” Darwin wrote in his book The Descent of Man,: “he who was ready to sacrifice his life, as many a savage has been, rather than betray his comrades, would often leave no offspring to inherit his noble nature” (p.163). Darwin began to wonder if sometimes a behavior that was risky for the individual could provide an advantage to the larger group of which he was a part: “a tribe including many members who...were always ready to give aid to each other and sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection” (p.166). [v]

Later scientists, dissatisfied with this explanation, began to realize that the individuals who were the beneficiaries of altruism tended to be the kin of the altruist. So even though I might end my own life before reproducing, if my close kin survived to reproduce, like sisters and brothers who share 50% of our genes, I would still have been genetically successful. A fellow called George Price even worked out an equation to show the mathematical relationship between genetic benefit and closeness of relationship (because cousins, for example, are not as beneficial to preserving your gene pool as your siblings)[vi]

Then in 1984 Wilkinson challenged the link between kinship and altruism with his research into the Vampire Bats. Over the course of the study he tracked which bats helped one another, and found that if you were a hungry bat, the neighbor bat who was most likely to help you was a bat you had helped in the past. It’s a remarkable, though relatively unique, example of altruism among unrelated neighbors. In a really wonderful “Radiolab” program on the topic, Wilkinson extrapolated that maybe 40,000 years or so ago something happened to all the large mammals in the area where the bats lived. There was a crisis in the bat food supply, and bats evolved this altruistic behavior so that they could survive as a species.

Scientists and philosophers argue that if there is any potential benefit to you, say the survival of your gene line, that results from your helping act- then this is not true altruism. They argue that perhaps true altruism does not really exist. But I disagree. The fact that altruism is a tool we have evolved help us survive is a hopeful thing. We have so often wondered if human nature isn’t, at its core, “red in tooth and claw.” We worry that the true nature of life is a fight to the death. But the fact that we are hard wired to help one another, and that in helping one another we help ourselves, shows that altruism, is part of our nature. Altruism is a piece of our survival story and built-in to who we really are.

Professor Abigail Marsh has spent her career studying altruism in humans. What makes people help another person at some cost or risk to themselves? In a recent study at Georgetown Marsh tested 19 altruistic people, the kind of person who would, for example, give a kidney to a stranger, and found everything she tested looked pretty normal except for the amygdala- the part of the brain that helps process emotional reactions. She found this part was “significantly larger” in the altruists she studied than in the regular population.[vii] She concluded that “The results of brain scans and behavioral testing suggest that these donors have some structural and functional brain differences that may make them more sensitive, on average, to other people's distress,”[viii] So Marsh’s research suggests that we help one another because we empathetically read their pain, their distress, and we act to alleviate that distress as we would our own.

In his Ted Talk Buddhist Monk Matthieu Ricard extends this idea further[ix]. He reminds us that empathy is a normal part of being a mammal, an extention of the instinctive mammalian drive to care for our young. ( Mammels are, by definition, those animals that nurse their young after birth instead of, say, laying eggs in the mud and leaving our young to fend for themselves once they hatch). Richard suggests that the problems facing us now- such as economic inequality and global climate change, will require altruism- will require people working for the good of future generations sometimes at the expense of our own present gain. Let’s take a moment to acknowledge some of these problems in our world that you think would altruism would be part of the solution. Go ahead and call our from your seat. ….. Richard wonders if our natural mammalian empathy could be expanded wider and wider to call forth such altruism.

I was amazed to learn recently that Lichen ( you know those crusty flowery plants that grow on the bark of trees or rocks?) are a mutualistic symbiosis. That means lichen are actually two totally different life forms, algae and fungus, living together as one organism. Both the algae and fungus can live alone, and in fact it stumped scientists for a long time what might make them come together as lichen. As Biologist Robin Wall Kimmerer writes in her beautiful book Braiding Sweetgrass:
“when researchers put the two together in the laboratory and provide them with ideal conditions for both alga and fungus, they gave each other the cold shoulder and proceeded to live separate lives, in the same culture dish, like the most platonic of roommates. The scientists were puzzled and began to tinker with the habitat, altering one factor and then another, but still no lichen. It was only when they severely curtailed the resources, when they created harsh and stressful conditions, that the two would turn toward each other and begin to cooperate… When times are easy and there's plenty to go around, individual species can go it alone. But when conditions are harsh and life is tenuous, it takes a team sworn to reciprocity to keep life going forward. In a world of scarcity, interconnection and mutual aid become critical for survival. So say the lichens.”
I thought back to those bats, 40,000 years ago, when some hypothetical catastrophe caused a crisis for their species, and in response they evolved the altruistic behavior that allowed them to survive. Life-saving changes are possible when we need them most. And I argue that this is one of those critical moments in the history of life on this planet. Richard notes that while it may take 50,000 years to make an evolutionary biological change, personal change and societal evolution can happen much faster. He reminds us that there is hard scientific data showing that structural changes[x] happen in our brains when we practice altruistic love, or loving kindness. Richard has thousands of hours of meditation practice in his life as a monk, but such structural changes are possible with as little as 4 weeks practicing loving kindness meditation just 20 minutes a day.

Mammals evolved empathy so that we would be hard-wired to care deeply about our offspring and others in our family group. And we know that for some extraordinary altruists that same empathy and compassion can extend all the way across the continent to a stranger who needs a kidney, or a refugee from a war far away. Could we extend that altruism to the next 7 generations of children yet to be born? Could we take Richard’s challenge to cultivate our own loving kindness as individuals and as a society? Could we extend our circle of loving kindness beyond our own kin, our own friends, to hold all of life itself?

When you are discouraged about human nature, remember that altruism is just as natural as competition. It is an important adaptation that is in our hard wiring. It is not only part of our nature, but part of the nature of Vampire bats, Vervet monkeys, and even e coli. Giving selflessly is not only the sappy stuff of Valentine’s Day stories; it is part of the scientific story of how we survive together.


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