Many would have us believe that it is a disadvantage is be social, generous, trusting, cooperative, unselfish or whatever it is called. But it is not a disadvantage, it is an advantage. Cooperation comes with costs like having to control cheaters but it is a very old and successful strategy. In this third post in the animal series, I look at social animals.
Comparative Neuro-biology 3: What can be learned from social animals?
Before we look at social animals, let’s look at very ancient cooperation. The difference between eucaryote cells and prokaryote ones is enormous. Prokaryotes such as bacteria are essentially just a lipid bag of water, salts, proteins, nucleic acid and carbohydrates. They have very limited internal structure and therefore very limited control over their metabolism. Eukaryote cells are also essentially a lipid bag but inside the bag there are many other bags. The DNA is inside a bag (the nucleus) and so access to it is controlled. The engines that burn sugar for energy are each in their own bags (the mitochondria) and the membranes are essential to the process of reaping energy. And so it goes for photosynthesis, protein manufacture, export from the cell and so on. How did eukaryote cells evolve? It seems to be that simple cells cooperated and eventually became so dependent on each other that they merged into a single more complex entity – one with extremely sophisticated control mechanism.
“Eukaryotic cells differ from prokaryotic cells by their more complex intracellular organisation. Distinct cellular processes are compartmentalised. This improves efficiency but a problem emerges. Different compartments need to exchange specific molecules and certain molecules need to be exported to the cell exterior. Since most molecules are too large to directly pass through membranes, a mechanism is required to deliver the cargo. The 2013 Nobel Prize in Physiology or Medicine is awarded to Dr. James E. Rothman, Dr. Randy W. Schekman and Dr. Thomas C. Südhof for their discoveries of machinery regulating vesicle traffic, a major transport system in our cells. This represents a paradigm shift in our understanding of how the eukaryotic cell, with its complex internal compartmentalisation, organises the routing of molecules packaged in vesicles to various intracellular destinations, as well as to the outside of the cell.” (Nobel press release)
So… cooperation in biology is very ancient and is the foundation of multicellular organisms: plants, animals and fungi. But the idea of multicellular organisms itself requires cooperation. The individual cells have to give up any selfish sovereignty to the organism. The cells, tissues and organs have to cooperate or the organism dies. By staying and working together they can live outside the ocean on dry land, eat many more varied foods and all the other things that plants and animals can do that bacteria cannot. Every once in a while some cell goes maverick and attempts to escape the multicellular restriction and we have a cancer. Most cells do not make it to the stage of a cancer because the organism has methods of finding and killing cells that cheat. Cellular slime molds are right on the edge of the divide between multicellular and single celled organisms. How do they deal with cheaters?
“Much of what we know about the evolution of altruism comes from animals. Here, we show that studying a microbe has yielded unique insights, particularly in understanding how social cheaters are controlled. The social stage of Dictylostelium discoideum occurs when the amoebae run out of their bacterial prey and aggregate into a multicellular, motile slug. This slug forms a fruiting body in which about a fifth of cells die to form a stalk that supports the remaining cells as they form hardy dispersal-ready spores. Because this social stage forms from aggregation, it is analogous to a social group, or a chimeric multicellular organism, and is vulnerable to internal conflict. Advances in cell labeling, microscopy, single-gene knockouts, and genomics, as well as the results of decades of study of D. discoideum as a model for development, allow us to explore the genetic basis of social contests and control of cheaters in unprecedented detail. Cheaters are limited from exploiting other clones by high relatedness, kin discrimination, pleiotropy (multiple effects of a gene), noble resistance, and lottery-like role assignment. The active nature of these limits is reflected in the elevated rates of change in social genes compared with nonsocial genes. Despite control of cheaters, some conflict is still expressed in chimeras, with slower movement of slugs, slightly decreased investment in stalk compared with spore cells, and differential contributions to stalk and spores. D. discoideum is rapidly becoming a model system of choice for molecular studies of social evolution.” (Strassmann 2011)
Then there is symbiosis. Organisms that are separate but live in intimate contact - corals and lichens for example. Lichens are an association of an algae and a fungus – they are successful on rocks that support nothing else. Corals are an association of the invertebrate coral polyp and an algae – its reef colonies are the foundation of a very successful ecosystem (at least until recent ocean changes). There are a lot of different types and degrees of symbiosis. It is a successful way of life.
Social insects (ants, termites, bees, wasps) are amazingly successful. Their cooperation is very evident and the obvious reason for their success. The social vertebrates are also successful. Throughout biology, where ever we look we find cooperation. From the tiny cells and their physiology, to organisms, to cooperating organisms, even to ecosystems, we find cooperation succeeds. So when someone says that cooperation is a strategy that fails – they are wrong. The proof that cooperation works is all around us. What are the game theorists missing?
(Aside: I have to say that the Prisoner’s Dilemma is not life. When there is a supposed simulation of the real world, the question to ask is exactly when and where this is a valid simulation rather than a useless mathematical/logical formula. That cooperation works and is wide-spread is an established fact, why this might be is the question that the game/simulation research is about.)
The problem with the Prisoner’s Dilemma as a model is that there is no communication and communication is key to cooperation. All the examples of cooperation have some level of communication. It can be physical contact, chemical exchanges, smells, visual signs, sounds; but there must be communication, an awareness of what the partner/s are doing. Communication is necessary for a level of ‘trust’, including the identification of a partner as legitimate at its simplest. No communication; no trust; no cooperation. Communication is not some little add-on but something important that living things do, internally and externally.
There are very impressive examples of cooperation in mammals, especially the hunting strategies of various dogs, cats and dolphins. We find that social mammals have ways of communicating that are similar to our non-verbal communication – no real difference of kind. Probably the oldest non-verbal channel is posture. When I used to give talks on non-verbal communication, I would point out that the different between taking an upright, head up stance and taking a low, head down stance is extremely old and very obvious in reptiles as well as birds and mammals. The tall pose is aggressive and the crouching pose is submissive. Postural communication is very clear in dogs, horses, primates – and that includes humans. The dog’s play-bow is a good example. It says, “What I do now is not meant to be taken seriously, it is just play. Come play with me.” Posture even can work between species. Apparently it works for huskies and polar bears, as has been shown on YouTube. “Here comes a wild polar bear cut off from his normal seal diet by the water-not-yet-ice … he comes upon a husky tethered in the snow … it looks like lunch time for the bear. … It is not hostility being exchanged between these two… note the the polar bear’s eyes are soft, the husky’s ears are back, his hair is flat and his mouth is open without showing fangs – just a few moments before, as the bear came into view, the husky was in a crouched (play) bow and a wagging tail… something beside attack is on their minds… two carnivores facing each other and, instead of a bear’s predatory attack to feed his hunger, something magical happens” … (see pictures at nifplay below)
I could give a long list of animal communications including everything from bacteria to apes but I will not. I think anyone would agree that communication is common among animals. The point I am making is that without communication we cannot have cooperation and without cooperation we cannot have social groups. Without social groups, we do not have culture. Culture is the big prize. Culture is what humans have in abundance and other social animals have only small amounts of. Culture is what allows us to visit the moon. We have an explosion of culture and that is because we have a great advance in communication, our languages.
Why do other animals such as the apes have communication and cooperation and even a little culture, but they do not have language and with it no explosion of culture? We could just throw up our hands and say, “that’s evolution”. But actually it is a very serious question. When we have chimps and bonobos in captivity and familiar with humans, it is possible to teach them rudimentary language using hand signs or computer tools. So it seems it should have been possible for them to have developed protolanguage and then like humans to have found it so useful that both biological and cultural evolution would have favoured it. But this did not happen. There are a number of other animals that ‘might’ have developed language but didn’t, although they have extension communication and cooperation – elephants and dolphins come to mind.
Blair Bolles in his blog Babel’s Dawn examined the origin of language for about 7 years. He came very close to the heart of the problem in the ideas: that language is dangerous as well as advantageous; and, that group evolution is possible. It is not always in an individual’s best interests to share secrets, let alone broadcast them. Animal communication seems to be limited to very stereotyped messages. Given non-group evolution it may be impossible for language to be selected for because it is often not to the individuals advantage. It is very difficult to show group selection in biological traits but cultural evolution is very obviously a result of group selection (it being groups and not individuals that have culture). We are talking about a little jump from the realm of predominately biological evolution to predominately social evolution. The bonobo is on the one side of that gap and we are on the other.
We know that captive chimpanzees can learn to use words and phrases but in the wild they never tell one another anything. They communicate to control. This kind of discretion is easy to explain in terms of individual selection. A chimpanzee who knows where there will be some ripe fruit has an advantage over its fellows. A chimpanzee who blabs his news has given up an advantage. The fitness score of the chimpanzee who keeps secrets is almost certainly higher than the blabbermouth’s score. Thus, even though groups might benefit from language, it is not going to evolve among chimpanzees. This kind of reasoning makes it easy to explain why language never evolved with other species, and hard to explain why humans have such a hard time keeping secrets. (see Bolles’ post below)
We have come full circle: communication facilitates cooperation, which facilitates culture, which facilitates communication and cooperation.
Image: Orpheus charming the animals by Jacob Savery
Eukaryote controls - Press releases about Nobel Awards
Strassmann JE, Queller DC; Evolution of cooperation and control of cheating in a social microbe; Proc Natl Acad Sci U.S.A 2011, 108 Suppl 2:10855.62. doi: 10.1073/pnas.1102451108