By Robin Walsh
It is commonplace today that chimpanzees are our brothers. They are 98% genetically identical to us, and they and bonobos are closer to us on the evolutionary tree (and vice versa) than gorillas or any other creature. Initiatives such as the Great Apes Project demand rights for our simian siblings, and lecture us on their intelligence and sociability—often counterposed to our own violent and selfish instincts, and have attracted the support of luminaries such as philosopher Peter Singer, the late comic author Douglas Adams, and the Spanish parliament.
Helene Guldberg’s excellent and clearly written new book critiques these assumptions, and importantly succeeds in making clear the absolutely key role of experimentation in understanding the natural world. She sets out numerous examples of how intuitive assumptions that we make about how animals act can be shown through experiment to be incorrect. These can include human interpretation of animal cues, such as the often woefully incorrect assumptions owners draw about their pets—such as that a dog looks ‘guilty’—or the fact that behaviours produced by conditioning or instinct seem ‘intelligent’. But these mistakes seem not only to have affected old ladies with too many cats, but a generation of primatologists.
Scientists such as Jane Goodall, Dian Fossey, and others leapt from observing their primate subjects behaviour to speculating about their minds, the emotions, and internal life that, to their annoyance, was considered unscientific by most of the scientific community. As Guldberg notes, while they did make some interesting discoveries, they also considered scientific rationality a straightjacket, and no longer felt the need to systematically and scientifically interrogate the anthropomorphic assumptions they held. This attitude to studying the great apes has affected many others, leading some into the kind of blind alley exemplified by a frankly embarrassing transcript, which Guldberg reproduces, of a scientist drastically twisting and reinterpreting the ‘words’ of their primate charge (which had been educated in basic sign language) to give coherent answers to interview questions.
Guldberg’s book reviews the latest published literature in psychology and other disciplines that explores the similarities and differences between humans and primates, to examine how close we are to our closest cousins. There has been much discussion recently about how different chimpanzee communities have different cultures, different patterns of tool use and behaviour, which cannot be reduced to genetic differences, and seem to slowly change over time. While Guldberg agrees that this is true, she does not believe it adds up to culture in the sense that humans mean it, which builds on the achievements of previous generations and reshapes the world around us; that is something that apes clearly have not been able to do.
Further, Guldberg argues that the mechanisms of chimps’ cultural interchange are very far from our own; they do not engage in teaching and learning, but instead pick up on others’ activities through stimulus enhancement (you become more likely to start playing with a stick if others are using one) and emulation (attempting to reproduce the result of another’s activity) rather than true imitation (the copying of how a tool is used). Chimps have to take a step back to square one each time knowledge is transmitted, having to discover an innovation for themselves through ‘aping’ their peers rather than truly learning from others in the sense that humans do.
Similar cognitive limitations show themselves in chimp tool use. As is clearly the case with spiders, ‘sophisticated engineering achievements’ tell us nothing about internal cognitive complexity, and likewise, an understanding that tools work is not matched with an understanding by chimps of how tools work. They make errors that seem obvious to us, such as pulling a cloth that is merely in contact with food, rather than underneath it, in an attempt to bring it closer to them. Likewise, their psychology shows big differences from ours—like a very small child, chimps seem not to possess a ‘theory of mind’, a conception that other beings have an internal life of their own. Humans, even young children, are able to abstractly understand causality and unseen forces, which chimpanzees appear incapable of doing.
So, what was the ‘black monolith’ factor that provoked the enormous divergence in capability between two such evolutionarily close animals? While there clearly were big changes in brain structure, these seem not to be directly linked historically with increasing cultural complexity of proto-humans; brain size is necessary but not sufficient, if you will. Guldberg suggests the real source of our differences is most probably in language. Chimpanzees do communicate, with alarm calls and other cries, but these could be termed ‘affective’ rather than ‘symbolic’; in other words, they are emotional calls analogous to crying or laughing, rather than the representational language of abstract concepts we speak with. The secret of humanity’s exceptionalism is the cumulative nature of human thought—learning, teaching, and abstract language enable us to plug into the collected wisdom not only of our direct social group, but people we have never met and those long dead. The human brain, when looked at in isolation, is not that amazingly more complex than a chimp’s, but collectively we have got something special. Guldberg’s book is much needed restatement of our humanity; why we are something more than ‘just another ape’.
Written under a Creative Commons License, with edits: https://creativecommons.org/licenses/by/1.0/