Thomas Suddendorf

Abstract

Thomas Suddendorf is Professor of Psychology at the University of Queensland, Australia. He was born and raised in Germany, but has spent most of his adult life in the Antipodes. He studies the development of mental capacities in young children and in nonhuman animals to answer fundamental questions about the nature and evolution of the human mind. He has received honors and distinctions for both his research and teaching, including awards from the Association for Psychological Science, the Australian Academy of Social Sciences, and the American Psychological Association. He has published in over 40 different scientific journals, including a paper in Behavioral and Brain Sciences on the evolution of foresight (co-authored with Mike Corballis) that Thomson Reuters recognized as one of the most highly cited in the field of neuroscience and behaviour. His new book The Gap — The Science of What Separates Us from Other Animals (NY: Basic Books) has been endorsed by various luminaries, including Jane Goodall and Richard Leakey, and has attracted outstanding reviews in scientific journals, including Nature and Science, and the press, including The Times and The Wall Street Journal, alike. What drew you to research on animal cognition and human evolution? As far back as I can remember, I have been fascinated by questions about why we are the peculiar species that we are. Why are humans, and not, say, baboons, running the zoos? Where do we come from and where are we going? During my adolescence I became disenchanted with the Catholic doctrine that we were taught in the small German town I grew up in. So I turned to science in general and biology in particular to gain a better understanding of nature and our place within it. Most of my psychological research, in one way or another, is still driven by these big questions. How did you end up down under? After completion of civil service as an ambulance man, I went backpacking through South-East Asia and discovered my love of travelling. I was fascinated by the novelties in the cultures and natural worlds I encountered. Upon my return I started studying psychology in Münster Germany, but promptly plotted further travels. I eventually moved to New Zealand to study for my Masters degree and stayed on to complete my PhD. As the job opportunities for a psychologist with an evolutionary perspective turned out to be rather limited in New Zealand, I moved across the Tasman Sea to take up a lectureship at the University of Queensland — and I liked it so much that I am still there. Did your career benefit from the move down under? I think it gave me greater freedom. I was very lucky to find a brilliant mentor in Michael Corballis at the University of Auckland, who allowed me to pursue ideas that ran counter to the prevailing Zeitgeist. For instance, the evolutionary approach to psychology in the 1990s was dominated by the ‘Santa Barbara School of Thought’, which emphasized a domain-specific view of the mind, whereas I was interested in the domain-general processes responsible for the tremendous flexibility of the human mind. I was especially interested in foresight, given the dramatic fitness benefits we gain from considering the future, whereas research in cognitive psychology was much more focused on memory processes. I found an idyllic houseboat that was moored in the swamps of Waiheke Island and wrote a Master’s thesis on the role of what I called ‘mental time travel’ in the evolution of the human mind. I proposed that episodic memory and our capacity to imagine future situations are intimately linked in mind and brain, and that the development of these capacities in our forebears was a prime mover in human evolution — for instance, because it allowed us to flexibly prepare for future threats and opportunities. That my ideas were unfashionable became clear when I tried to get them published — I think I resubmitted the paper eight times and eventually had to settle, after three years of trying, for a small journal I expected no one to read. But eventually some people did. You just wrote a book, ‘The Gap’, about what sets humans apart from other animals do you believe in some kind of human exceptionalism? No. Biology makes it plain that we are just another species of primate. As Gilbert and Sullivan put it so memorably: “Darwinian Man, though well behaved at best is only a monkey shaved”. While such reminders of our animal nature are a counterweight to the common notion that humans are somehow at the apex of existence, I think this should not obscure the fact that we are rather peculiar. Of course, every species is unique, and in that sense humans are no different. But I want to know why we have changed the face of the Earth and control much animal and plant life, whereas even our closest animal kin have remained unobtrusively in their forests. We have been extraordinarily successful, adding up to several times the biomass of all other wild terrestrial vertebrates combined. So I think the differences between us and other animals deserves careful scientific attention. Over 10 years ago, I set out to collate the relevant evidence and integrate it into this book to clarify what is known about the nature of this gap — it feels like my life’s work. Why have we not long established a scientific consensus on this fundamental question? Establishing the mental capacities of other creatures is a difficult task that requires careful tests that rule out alternative, leaner explanations. Establishing the absence of capacities is even more difficult, because a universal negative claim only requires one compelling case to reject it. Only when we give species many opportunities to show us a capacity and they consistently fail, can we gain confidence that the trait does not exist. After all, absence of evidence is not to be mistaken for evidence of absence. Furthermore, when it comes to humans and our position in nature, I think there is a risk that preconceived notions about how the world should be may influence what researchers do and how they interpret what they find. Comparative psychology sometimes seems to be a field divided between those who are keen to demonstrate sophisticated animal capacities and those who are particularly reluctant to do so. Dan Dennett calls them the romantics and the killjoys. Debates between these factions over rich and lean interpretations of animal behavior are persistent, and there have been few attempts at reconciliation and integration into larger explanatory frameworks. So are you a romantic or a killjoy? Both (or should I say neither). Often the extreme positions are not as far apart as they at first appear. For example, animal capacities may be much more sophisticated and varied than we currently know, and nonetheless the human mind may be profoundly different. Even the apparently irreconcilable disagreement over whether there is a difference in kind that sets us apart from animals and Darwin’s belief that human and animal minds only differ in degree, may in fact both contain elements of the truth. We know that changes in degree frequently produce distinct attributes that may well be regarded as a difference in kind: just think of the effect gradual increases in temperature have on the properties of H2O. Similarly, gradual changes in working memory capacity can lead to radically different possibilities of thinking. Other stark disagreements sometimes simply reflect differences in opinion about the relevant criteria rather than about matters of fact. To demonstrate language, for instance, is it enough to demonstrate that other animals communicate, or must they be able to have debates or tell stories? Rather than trying to defend human superiority or to debunk human arrogance, I aim to provide a balanced overview of the current knowledge about the abilities and limits of mental abilities of animals. There is no point in denying our primate heritage, nor in belittling that we have extraordinary powers. I think of my book as a starting point, a call to arms, if you like, towards a dispassionate science of what we share and what sets us apart from other animals. By contrasting humans with animals, are you assuming there is something like ‘the animal condition’? Although some traditional views have assumed that non-human animals have essentially the same learning capacities, we now know that that is not the case. In fact, there is considerable research documenting the distinct cognitive capacities of, for instance, various species of primates and corvids. I suspect we are only scratching the surface. We need more research on other species. There are likely more, and more diverse, animal cognitive capacities than is widely assumed, and they may not only be found in big-brained vertebrates. The behaviors of, for instance, octopi or Queensland jumping spiders suggest that convergent evolution has produced a range of other means of driving clever behavior. When one is interested in human evolution, comparisons to our closest surviving animal relatives, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus), are of particular interest, and I have conducted studies with chimpanzees for that very reason. Remember, however, that chimpanzees are more closely related to us than to the other African apes, the gorillas. So from the perspective of chimpanzees, we are their closest relatives. In some sense, therefore, studying them may tell us more about ‘the human condition’ than about ‘the animal condition’. What is your favorite experiment? That is a tough question given that there are many fascinating and clever studies in animal cognition. If pressed, I would probably single out a brilliant experiment by Victoria Horner and Andrew Whiten in which they presented chimpanzees and human children with a puzzle box and showed them how one can get a treat inside. The process involved first poking a stick into a hole at the top part of the apparatus and then inserting it in another hole further below. Both chimpanzees and children readily copied both actions of the model to retrieve the reward; however, when the apparatus was made out of transparent material it became patently obvious that the first action, poking into the top, had no causal role in the opening of the box, and in this condition chimpanzees simply poked the stick into the lower hole to obtain the reward, whereas the children continued to copy the superfluous first action. This is a wonderful study because in one sense the chimpanzees acted more efficiently, and arguably more rationally, than the children — and yet, the copying of unnecessary acts by children demonstrates a potentially critical human capacity for faithful transmission of cultural knowledge and for accumulation. Human culture can be maintained over generations without shortsighted youngsters abandoning all the hard-learned lessons. What is the best advice you’ve been given? The first thing to spring to mind is a valuable piece of advice Russell Gray gave me before I left the University of Auckland to take on a lectureship at the University of Queensland: “Learn to say: No”. I am still trying to get better at that one. What would you like to see changed in your field? We need more replications. Sometimes, single sensational claims may do more harm than good. For progress we need systematic replication and perhaps a way to collate failed attempts (even though failures can typically be due to any number of reasons). Establishing limits can be just as important as establishing capacities. Who is important in your career? Michael Corballis was a wonderful advisor for both my Masters thesis and my Doctoral work. He is an extremely well-rounded academic gentleman, who has retained a boyish wonder about the world and its quirks. I am not sure if I would have persisted with an academic career had I not met him. The other person I must single out is my spouse, Christine Dudgeon, who is actually the real biologist in our family. She studies sharks in their natural environment and examines their genetics and ecology. One nonhuman I would like to mention is the chimpanzee Ockie — one of the animal stars in my book — who sadly passed away the month it was published. Which aspect of science, your field or in general, would you wish the general public knew more about? Evolution. Naturally, I think that the questions that drive my research, Where we come from, what we are and where we are going, are rather important. By demystifying our curious place in nature, I hope science can contribute to a more enlightened self-awareness than the traditional views about our special roles that continue to fuel so many conflicts on this planet. Science increasingly allows us to gain a better understanding of the long-term consequences of our action. Once aware of these consequences we become morally responsible to take them into account. We must cooperate more to conserve habitats and biodiversity. I am particularly concerned about the future of our closest remaining animal relatives. I like the pun “Plan it for the apes” — because we can.