Wednesday, August 2, 2017
Kevin N. Laland. Darwin’s Unfinished Symphony: How Culture Made the Human Mind. Princeton: PUP, 2017. 464 pages. Illustrated. ISBN: 9780691151182. $35.00US
Kevin Laland, professor of behavioral and evolutionary biology at the University of St. Andrews, presents an excellent and thorough discussion of how human culture in feedback loops adapted the mind to tackle ever increasing complex social and technological problems. While there are many fine books on culture and evolution, such as P. Richerson and R. Boyd’s Not By Genes Alone, A. Mesoudi’s Cultural Evolution, M. Pagel’s Wired for Culture, and G. Hatfield and H. Pittman’s Evolution of Mind, Brain, and Culture, Laland’s book is both a product of decades of research in his Lab and a result itself of cultural evolution, drawing from previous authors. No one book should be read and relied on; students need a range of voices. What’s different about Laland’s work is how, following the extended evolutionary synthesis, he places emphasis on humanity’s (his word) unique (his word) cognitive capabilities to develop a cultural mind through innovation, teaching, high-fidelity copying, and learning. A worthwhile book to study, I’d recommend this for anyone – across disciplines – interested in learning about cultural evolution. Like others before him, Laland rightly believes biology can explain some of our complex social systems and technology; indeed, he does admirable work in a book filled with details and discussion on the science of culture.
Let me summarize most of Laland’s extensive argument and then get into some specifics. A cultural drive evolved through natural selection via the benefits of precise copying. Human intelligence and cognition increased because of many factors, ranging from better diets to sociality, and subsequently cooperative learning increased. The reason human beings have such complex culture is attributable to their high-fidelity copying, both maintained and innovated on through social transmission and especially teaching. The rising degree of social learning fed into conformist (i.e., cultural) norms. From the emphasis on teaching, language probably evolved as an adaptation to make teaching more effective. In this way, genes and culture co-evolved, evident in the gradually increasing importance and spread of tool use and other technologies across hominins. The gene/culture co-evolution feedback prompted brain expansion and innovations that helped fuel, over hunter-gatherer societies, agriculture and farming, which in turn led to cities. Subsequently, the scale of physical and psychological cooperation exploded, demanding further teaching and learning as well as division of labor and organized social structures.
In Laland’s view, modern physical and artistic cultures have not necessarily given any reproductive benefit. Likewise, he sees no sole originator in the evolution of mind – rather, each new innovation enabled cognitive feedbacks to engender yet more development. Though not discounting our continuities with animal predecessors, Laland clearly sees us as special: He often uses the adjective unique in describing our humanity, a noun of which he is fond. What seems to be different about us, according to Laland, is our ability to teach. We don’t just assist or give aid to offspring and kin; we actively engage in learning and instruction, keys to our massive neural plasticity, innovations, and expansive niche construction. We maintain what we’ve learned, share the information, and improve upon it through various methods, all of which equate to cumulative culture.
In other words, our capacity for culture is probably responsible for human intelligence and language. Innovative behaviors can happen in other animals quickly, which means they are not traceable, as with us, to genes but to simple learning. Of course the human career is a long story, so Laland’s claim for human uniqueness and separation from other primates includes the lineage from australopiths to anatomically modern humans. In two words he narrowly sees any connection between us and nonhuman primates as “superficial similarities” (15), and he insists on a rather large gap between us and even great apes. No one would say we are chimpanzees. Some human/chimpanzee genes don’t necessarily function similarly; and there are no copies of some human genes in chimpanzees. Even down to the axon, the splicing of genes can reveal considerable human/chimpanzee differences, notes Laland, to say nothing of the switching on/off sequences of genes. The largest difference of gene expression between humans and chimpanzees appears in the brain and, Laland goes on, the chimpanzee brain is physiologically closer to a monkey’s than to a human’s.
While he seems to paint a black-and-white picture here, a key consideration is this: Early in our hominin lineage we were closer to a great ape; our cultural creativity enabled the vast differences between us and nonhuman primates over the course of millions of years. I should say, however, that some studies (perhaps too recent to appear in Laland’s book?) point to great ape full theory of mind. See, e.g., Christopher Krupenye, et al., 2016, (“Great Apes Anticipate that Other Individuals Will Act According to False Beliefs.” Science 354.6308. 110-114) and especially David Buttelmann, et al., 2017 (“Great Apes Distinguish Truth from False Beliefs in an Interactive Helping Task.” Plos One 12.4. e0173793). Krupenye’s paper is co-authored by M. Tomasello and J. Call, whom Laland relies on to stress what appear to be black-and-white differences. But Laland’s overall point is, simply, that hominin evolution clearly took several major upsurges as opposed to nonhuman primates.
Laland, for instance, labels as remote any indication of ape language, including those who’ve been taught to sign, since they do not use grammatical syntax on their own. This, however, is splitting a hair between intellectual capacity and ability. It almost seems that in order to bolster his repeated claim of human uniqueness and superiority Laland must lower the capacities (potentials) and abilities (actions) of nonhuman primates. As one example, Laland resists acknowledging any moral sensations in animals but yet admits to their complex emotions. Emotional responses are directly tied to what we label moral behavior. Contrary to his dismissing ape morality as “romantic” (24) we need to admit, without using the problematic word morality, that nonhuman primates and especially great apes have social intelligence and often exhibit caring, empathy, and most notably self-control. No wonder, in my reading of Laland, he seems indifferent to the work of someone like Frans de Waal. For instance, Laland says that emotions do not equate to morals (25). While to some degree technically true, a good interdisciplinary study that pairs moral philosophers with primatology on the moral senses could chip away at that assessment. To support his claim, Laland cites numerous cases of animal indifference to others, exploitation, or self-serving behavior. Surely, we tend to be an overwhelmingly caring and helping species, but it’s inaccurate to ignore our continual amount of maliciousness. The philosopher Arthur Schopenhauer put it best in the early nineteenth century in his book On the Basis of Morality. Schopenhauer talks about the difference between human beings and animals: We can be maliciously harmful to one of our own species for no reason; we will deliberately inflict pain, and not necessarily for our survival. So how does that make us morally superior?
I quibble. At any rate, the bulk of Laland’s argument deals with teaching and learning, both of which have achieved incredible complexity not seen in other species. This is not to say there is no social learning in apes for food resources, like termite fishing or nut cracking. Bird species that migrate transmit directions to youngsters. Even in the case of some fish species, one sex will copy another in mating behaviors. Laland details these examples and some of the experiments he and his Lab team conducted concerning guppies. Many fish learned by observing one demonstrate the best route to food, in some cases even when the way to the food resource is longer than another. This is social learning. In terms of predation, built-in instinctual responses are not enough, for one must learn socially how to elasticize responses to predators. For example, a rhesus monkey raised in captivity does not fear snakes, which is one of its main predators in the wild. So that’s a learned behavior.
Why copy, asks Laland. Not only to learn but to socialize. There is asocial learning, where one works alone and often makes mistakes, as in food theft. Asocial learning is costly but can offer big payoffs. There is also social learning, important especially in dealing with challenging environments. In social learning one garners information second hand. For example, Laland tells us, birds and other species learn to forage remnants of food resources directly acquired by another species. While natural selection seems to favor the copying behaviors of social learning, the asocial learners are crucial in discovering the actions to be copied. For humans, Laland says social learning became strategic copying (56). Copying without innovation reduces costs. It pays to see how well others benefit, or not, when exerting effort. If current practices yield a low payoff, what are others doing to benefit themselves?
There is game theory here, and Laland and his team devised a tournament which revealed that observant social learning over time paid off more/better than always trying to innovate. Asocial learning tends to be beneficial under extreme circumstances. Importantly, though, Laland’s Lab experiments, mathematical models, and aggregation of literature reviews lay stress not on simple copying but on flexible, precision copying. Good copies of copies ensure that if one successful strategist dies there’s a reliable copy somewhere. These findings play out in long and well-written narratives Laland offers, for instance, about stickleback fish and how they share and rely on information from others. As per game theory, in some cases fish would copy feeding habits more when they saw greater numbers of fish feeding at certain locations. While Laland admits to learning and innovation across species, he drives home the point that “humans alone” (102) have a monopoly on innovation.
Laland follows Allan C. Wilson: If problem solving and copying are coded in the brain, then natural selection would enlarge brains to be more innovative which, in turn, would further increase brain structures. As Wilson generally predicted about intelligence (innovation) and brain size, primates with larger brains are more flexibly creative and copy each other more often. In this way tool use might have been a feedback offshoot of gradually advancing social learning, which helps any innovation spread. Selection would then favor the social learners, magnified by the number of innovations, and so the feedback loops. Why big brains when even honey bees can copy, asks Laland. His point is that larger brains do more than make duplicates – they copy precisely and can even innovate from the copy.
In larger brained species, alternatives come into play when copying, and this is related to sociality or attention to the behavior and social nuances of others. A cultural drive begins to take hold and is favored by natural selection since there are survival payoffs to efficient copying with innovation. Hence, larger brains can facilitate problem solving abilities, comprehension, and fast learning. Cutting against the modularity of evolutionary psychology, Laland argues that there is high general intelligence across social learning primate species: capuchins, baboons, macaques, and great apes. The fundamental basis of primate intelligence, Laland’s Lab concludes, consists of several elements selected for and cultural, like infant dependence and learning, an extended life history, and activity in a large group. In accord with Terrence Deacon, Laland reminds us that when brains evolve parts once separate connect. A large brain is not essential for social learning, but a larger brain permits better copying by allowing different brain regions to communicate. Corvids, like apes, have large brains relative to body size, with an enlarged frontal area. High-fidelity copying favors ratcheting where innovations are improved upon. Laland’s mathematical models suggest that precision copying advances significant change well beyond local stimulus enhancement, typical for most species. Importantly, what’s learned is passed on culturally and then tinkered with.
How is culture learned, asks Laland. Through teaching, which is a vital adaptation for humans and related to cultural cooperation. Many other species learn on their own without active intervention. However, Laland says there is evidence that teaching (i.e., one’s behavior is modified so as to instruct another) occurs in meerkats, ants, bees, pied babblers, the superb fairy-wren, and possibly in cats, cheetahs, and tamarins. Chimpanzees, in contrast says Laland, do not engage in teaching; one observes and then works through trial and error. Since this type of social learning is evolutionarily effective, it does not pay for adults to expend costs in teaching. For humans, however, there is very little individual trial and error learning and much more coaching via cumulative culture. Teaching is evident in cooperative breeders: humans, ants, bees, meerkats, and pied babblers. For example, human children will cooperate and demonstrate for each other, in contrast to other primates like capuchins or chimpanzees.
An important component to Laland’s argument is the evolution of language – there are connections in speech, mentality, teaching, and learning. I particularly enjoyed the chapters on language and gene/culture co-evolution, pivotal to claims centered in the book. Communication for nonhuman primates is typically not learned and with little change. Whereas other animals have somewhat fixed calls, our language needs to be learned because the content is always changing. The cultural drive, Laland explains, that ratchets complexity is dependent on teaching and learning, bodily gestures and eye movements as well as verbal utterances; this combination of subtleties in teaching is really only human. As part of the extended evolutionary synthesis, language for our ancestors was the means to instruct efficiently in a cultural niche dependent on learning.
According to Laland, language evolved in terms of teaching and then broadened out to general cooperation. Moreover, language is probably implicated in hierarchical, sequence structures or the process of learning in stages. Here, too, Laland’s team worked on an extensive human subject experiment to find that rather than imitation, education with language most likely played a functional role in early Oldowan stone tool manufacture. In turn, evincing gene/culture co-evolution, the use of the tools would have favored selection for improved language, evident in more refined Acheulean tools later. Laland offers a comprehensive explanation of some examples of gene/culture co-evolution, such as right-handedness and lactose tolerance: “culturally modified environments are capable of creating unusually strong natural selection...” (216). Gene/culture co-evolution over sexual selection accounts for changes to skin color, body shape, hair types, eye colors, and even behaviors like mate choice. In fact, Laland says that gene/culture co-evolution might be, for humans, the major form of evolution. To recapitulate: Culture is teaching and learning, relates to tools and so impacted hunting and butchering, which led to fire and cooking, and so expanded the environmental range of hominins, and diversity across all of the preceding increased cultural practices as the physical environment became controlled, not threatening.
Key here is the rise of farming and agriculture that permitted groups to expand into cultural societies. In contrast, says Laland, hunter-gatherers have much less cultural evolution since they are mobile, forage, and can’t carry around lots of goods. With a smaller group there are, statistically, fewer innovating individuals. Agriculture, on the other hand, became a critical niche construction. Certainly after the last ice age a warmer climate was conducive to plant domestication, but there had been warmer periods before and no other hominin species farmed. This means that the rise of agricultural based societies was cultural and not environmental, according to Laland, from a human mind that had been increasingly developing technology and ecological knowledge to deal with the environment. It’s a long story, told best by Laland over many pages, and there were health costs associated with farming. But the advantages of being able to control large volumes of food for many people outweighed costs. Hierarchical societies emerged with a division of labor to increase productivity. In terms of selection, look at the results, says Laland: Agriculturalists were able to do more than hunter-gatherers, like expand populations, innovate more/better tools, and create complex social structures. It’s difficult to discern if there is a value judgment here (probably not), or if Laland is speaking only as a biologist. The most famous example of a small group that lost its cultural know-how is the Tasmanians, who, once separated from mainland Australia because of rising sea levels about 10kya essentially lost their tool-kit knowledge.
In terms of differential fitness, larger groups with more technology in a growing feedback possess the means for variation and selective cultural inheritance. Top this off with our immense capacity to cooperate and share norms of behavior, and so we have the story of the human career and what Laland labels as civilization. Groups that were more technologically efficient and more cooperatively effective were selected over others and thrived; surviving groups, in Laland’s schematic, were those who consistently engaged in massive cultural transmission or the social teaching to and learning by non-kin.
Laland ends his book with a chapter on the arts, but it is too wide-ranging than some others, like the outstanding chapter on cooperation. Eventually he focuses on dance, which involves collaboration synchronization, but takes long to get to his main ideas. Laland emphasizes dance because it includes music, visual effects, and fashion, though he presents a recent, historical perspective that ignores art in prehistory as cultural adaptation. While some authors might draw continuities to other species, and demonstrated elsewhere in this book, Laland pulls back. And for readers conversant in Paleolithic art and material cultures from the long Pleistocene, this chapter might seem a bit thin – but it fits nicely with the book, is well written and argued, and provides an important capstone. Epitomized in dance is our complex culture that relies on the social nature of learning, teaching, and cooperation.
In a few words and to reiterate my opening, I highly recommend Kevin Laland’s book Darwin’s Unfinished Symphony for biologists and students in the humanities alike. After decades of work and thought the book captures and explains in detailed, lucid prose important findings in cultural evolution and the extended evolutionary synthesis.
- Gregory F. Tague, Ph.D., professor of English, St. Francis College (NY), author, recently: Making Mind: Moral Sense and Consciousness (2014) and Evolution and Human Culture (2016).
Copyright©2017 by Gregory F. Tague – All Rights Reserved. This review will also appear in the journal Consciousness, Literature and the Arts