Picking up where Darwin left off

A devoted evolutionary biologist in Scotland has spent three decades studying how human achievement evolved from animal behavior Judy Siegel-Itzkovich reports.

A detail of British artist John Collier's 1883 painting of Charles Darwin is displayed as part of an exhibition in Darwin's former home. (photo credit: REUTERS)
A detail of British artist John Collier's 1883 painting of Charles Darwin is displayed as part of an exhibition in Darwin's former home.
(photo credit: REUTERS)
The famous March of Progress drawing of 14 apelike forebears of man in a parade ending with modern Homo sapiens – representing some 25 million years of human evolution – was rather oversimplified and misleading. It seems as if each stage evolved linearly to the next and took the same amount of time until humans began to speak, write, read, teach, innovate and establish a civilized culture, science and technology.
In fact, the path is much more complicated.
Have you ever wondered why chimpanzees – whose genome is 98.5% similar to that of humans – have never managed to produce a comprehensive language, invent computers or fly into space? Toddlers in nursery school are much more intelligent than monkeys.
But all human achievement evolved from its roots in animal behavior.
Kevin Laland, a professor of behavioral and evolutionary biology at the University of St. Andrews – Scotland’s first university established in 1413 – has spent three decades along with many colleagues with one key aim. He wanted to comprehend the most mysterious and complicated aspect of the human story – an explanation of how our evolutionary processes created a species so very different from that of lower species.
A fellow of the Royal Society of Edinburgh, the Scottish scientist has also been president of the European Human Behaviour and Evolution Association and editor for three years of Animal Behaviour.
Darwin’s Unfinished Symphomy: How Culture Made the Human Mind is his brilliant, 450- page, $35 book just published by Princeton University Press. The text is so detailed that 61 pages of the hardcover volume are dedicated to notes, 56 pages to a bibliography and just seven to an index. It reaches the conclusion that “our extraordinary accomplishments can be attributed to our uniquely potent capability for culture: social learning, imitation and teaching.”
Selection for more efficient and more accurate copying, he writes, caused primates to “rely on socially transmitted information, and this process supported culture, comprised of data banks of valuable knowledge.
For our ancestors, the result was a runaway process in which different components of cognition fed back to reinforce and promote each other, leading to an extraordinary growth in brain size and the evolution of high intelligence,” Leland continues, arguing that human minds are not just built for culture; they are built by culture, which was the engine behind the evolutionary process that produced accomplished humans.
The author, who goes into intricate detail on his studies of the behavior of animals, learned a lot even from major differences in copying behavior in two varieties of fish called threespine and ninespine sticklebacks as they swim in an aquarium.
“This book began with an innocent glance out of the window to contemplate the entangled bank of human culture,” he writes in his epilogue. The glance belonged to Charles Darwin, author of On the Origin of the Species, who published his book on November 24, 1859 and one day looked out of the English countryside from his study at Down House.
“It is interesting to contemplate an entangled bank, clothed with many plans of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, have all been produced by laws acting around us,” Darwin wrote in his most famous work.
“Thus from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows.”
Laland and his colleagues can be considered “intellectual descendants” of Darwin, who left an “unfinished symphony.” Darwin handed down an evolutionary theory that deals almost exclusively with “genetic inheritance and processes that change gene frequencies.” But Laland thought this was inadequate in explaining how human society developed and advanced.
He looked out his own window in St. Andrews, a small town in southeastern England. He, too, wondered, but thanks to what scientists have learned since 1859 at a spot more advanced than Darwin’s.
“I wonder, can evolutionary biology explain the existence of chimneys, cars and electricity in as convincing a fashion as it does the natural world? Can it describe the origin of prayer books and church choirs, as it does the origin of the species? Is there an evolutionary explanation for the computer on which I type, for the satellites in the sky, or for the scientific concept of gravity?”
Obviously, the human race has evolved and developed (and also destroyed). But, he asks, why haven’t “other apes” while having “traditions for eating specific foods or singing the local song” – called animal cultures” by scientists – managed to develop laws, morals or institutions? Why have we become distinct from their primate ancestors and produced a “majesty of human culture?” After dedicating his scientific career to dealing with these questions, Laland is ready in his epilogue to offer “some semblance of an answer. Certainly it is not the whole story.
Probably there are elements that I have got wrong. Undoubtedly I have not done justice to the contributions of others.”
Better food helped the brain to grow, for lives to be longer, for the population to grow.
This made it possible for people to learn more and create new things, along the way learning from and talking to each other so they could invent new things.
Chimpanzees, he writes, “can teach one another how to get ants out of holes using sticks, but none has ever been accused of figuratively standing on the shoulders of other chimps to develop a more complex or superior variant of this simple technology. Their technology, then, stagnates at this simple stage. Chimp-tech does not become increasingly complex, as ours has.”
He explains that “complex culture requires high-fidelity information transmission.” Our ancestors, he continues, learned to transfer knowledge accurately from one generation to the next “through teaching, which is rare in nature but universal in human societies, once the many subtle forms it takes are recognized.”
For the first time in history, notes Laland, a species “taught their relatives across a broad range of contexts.” Language developed as an “adjunct to teaching.” Uniquely, man has “an ability to pool our insights and knowledge and build on each other’s solutions.”
In addition, he credits the domestication of plants and animals and the advent of agriculture for the growth of human society and its complexity. Oral traditions and historical accounts, assisted by writing, led to today’s books and computer banks, “which left cultural knowledge increasingly difficult to lose.”
Just as dance evolved and humans were able to move in time to music, people learned to coordinate, cooperate and “synchronize our actions with others, making it possible to build a building or a city and then an interactive human society. Our abilities to think, learn, understand and communicate leave humanity genuinely different from other animals.”
Think, he writes, how complicated it is to build a school, for example. A large number of people using their hands and machines build foundations, walls, doors and windows, install pipes and electricity lines and paint what is built. The raw materials are developed by contractors in other businesses.
Before that, people designed the tools, smelted the iron and made plastic and rubber.
One school is only part of a huge enterprise that involves roads, hospitals, shopping malls, homes and recreational centers. “Such procedures are so commonplace that we now entirely take it for granted that the school will be built, and even complain if completion is a little late.”
New technology is the result of cooperation, as few things have been developed by one person alone. Laland tells the story of the ordinary paper clip, which was not invented by a single person bending a piece of wire into its utilitarian shape. Only in the Middle Ages was paper – first developed in the first century CE by the Chinese – produced in enough quantities so that the pages had to be bound together. A variety of people invented various pins and fasteners to hold them together, but they rusted and were not practical. The first paper clip design was patented in 1867, but it took many more years until people learned how to refine and mass-produce them.
Much of the book is devoted in painstaking detail from his own team’s lab research on how animals “invent new behavior and copy the good ideas of others” of the same species. They learn to find and process food.
Birds learned to catch rabbits and kill them by dropping them onto rocks; apes learned to remove palm hearts from palm trees despite their painful spines.
Rats are very intelligent rodents. Humans tried to kill them with poison in traps, but some rats that got sick and didn’t die learned and avoided the poison. Scientists spent decades studying the ways that adult rats influenced the eating patterns of young rats so they eat healthful foods and leave the dangerous food largely untouched, Laland writes. They teach even by leaving scents at good feeding sites and bad.
Fish secret mucous not only to swim more efficiently but also to leave food cues to others. Bees find plentiful sources of nectar that they bring home to their nests; they deposit scented solutions in the honeypots and teach other bees in the colony to prefer certain floral scents. “Eating what others eat is a highly adaptive strategy, provided effective mechanisms are in place to prevent ‘bad’ information from spreading.”
Fish are “good learners and are convenient model systems for studying many aspects of social behavior” that in primates would be almost impossible to duplicate. Leland and colleagues spent 20 years observing fish in lab aquariums. A doctoral student of his collected sticklebacks, of which there are 16 different species. She brought in a type with three large spines and another with nine small and harmless ones on their backs.
Using transparent barriers in the fish tanks, Laland and his team learned that the threespined sticklebacks were more protected from attackers because swallowing them was difficult and painful, while those with the nine little spines caused attackers no problem.
Thus the ninespines hid when threatened and the threespines were much more sure of themselves.
“Sticklebacks are capable of adaptive tradeoff in their reliance on social and asocial sources of information, mixing their prior knowledge of [food] patch quality with the information gleaned from observation of others in a surprisingly sophisticated way.”
Orangutans learn to use their hands as a megaphone to make their calls sound deeper and make themselves sound bigger to scare off predators.
Humpback whales learn songs through social learning, the author explains. But the whale songs are distinct, with those of humpbacks in the Pacific Ocean different than those in the Atlantic and Indian Oceans. When scientists detected a novel song in whales off the east coast of Australia, they monitored it and found that in 1998, just two years later, all recorded whales in the Pacific were singing the new tune.
Humans also learn from copycat behavior, sometimes tragically. “Marilyn Monroe’s death, for instance, which resulted from an overdose of barbiturates, was followed by an increase of 200 more suicides than average for that August month.”
Through natural selection, Laland continues, copying of behavior became more efficient and accurate, leading to the evolution of complicated use of tools and better nutrition. Unlike animals who are regarded as helpless infants for a short period, humans remain as “minors” for at least 18 years, giving their parents and teachers time to inculcate them with more knowledge and skills.
This innovation and social learning, he concludes, “was the driving force behind the evolution of the large primate brain and the advanced cognition, language and cooperation of humans.”
If only man would use his large brain to better cooperate in a fight against war, terror, hunger and ignorance.