Are mammals moral?

Frans de Waal
Primates and Philosophers
How morality evolved
230pp. Princeton University Press. $22.95; distributed in the UK by Wiley. £14.95.
978 0 691 12447 6

Richard Joyce
The Evolution of Morality
288pp. Bradford Books / MIT Press. $32.
978 0 262 10112 7

Lee Alan Dugatkin
The Altruism Equation
Seven scientists search for the origins of goodness
224pp. Princeton University Press. $24.95; distributed in the UK by Wiley. £15.95.
978 0691 12590 9
 
 
Many criteria have been put forward to provide a definition of what makes us specifically human, such as language, tool use, or consciousness. Most of these have crumbled, or at least become less exclusive, under the impact of scientific discovery. Chimpanzees can learn simple forms of language; a variety of animals, from apes to vultures and sea otters, can use tools; inasmuch as it is possible to be certain that other individuals are conscious, we now strongly suspect that this is the case for apes, dolphins and, most recently, Asian elephants. Faced with this erosion of our specificity, one of the few remaining exclusively human characters would appear to be our moral sense.

Frans de Waal’s excellent and thought-provoking new book, Primates and Philosophers, examines how morality might have evolved by looking for moral behaviour in our closest animal relatives. De Waal is a US-based Dutch scientist whose work has revolutionized our understanding of primate behaviour. His findings have been distilled in his highly successful popular science books, including Our Inner Ape (reviewed in the TLS, March 3, 2006) and The Ape and the Sushi Master (TLS, July 13, 2001). In 2004, de Waal gave a series of lectures at Princeton University on the subject of “primate social instincts” and their relation to human morality. These lectures, summarized in an eighty-page essay, form the heart of Primates and Philosophers.

De Waal’s aim is twofold. First, he wants to convince us that primates, and in particular the great apes (gorillas, chimpanzees, orang-utans and ourselves), show behaviour that can be interpreted as a product of morality. Second, he seeks to use these data to undermine what he calls “veneer theory”. This is the idea, which he traces back to T. H. Huxley, that human morality is a thin “veneer” laid on top of a brutish and selfish core, a view that implies a fundamental discontinuity between humans and our closest animal relatives. In other words, this is not only a discussion of how we became moral, but also of what we really are. The key question addressed by de Waal is whether non-human animals “possess capacities for reciprocity and revenge, for the enforcement of social rules, for the settlement of disputes, and for sympathy and empathy”. All of these characteristics, he argues, are required for the existence of morality, but the one he discusses in most detail in its animal context is empathy. Highlighting the relative dearth of investigations into empathetic responses in animals, compared to, say, studies of tool use, de Waal provides a series of examples of empathy in chimpanzees, ranging from the anecdotal to the experimental.

Probably the most striking example is that of Kuni, a female bonobo chimp, who found a stunned starling. She picked it up, climbed to the top of the highest tree, and “then carefully unfolded its wings and spread them wide open, one wing in each hand, before throwing the bird as hard as she could towards the barrier of the enclosure”. It is hard to interpret this behaviour in any other way than by saying that Kuni was empathizing with a member of another species. Empathy implies having “a theory of mind” – an animal needs to be able to recognize that other individuals also possess attitudes and emotions. Nearly thirty years ago, de Waal first showed that, after a fight between two chimpanzees, another, uninvolved individual will come to put an arm round the defeated individual, in an apparent gesture of consolation. This phenotype is limited to the great apes, though many primate species show “reconciliation”, when the two combatants will subsequently groom each other.

De Waal convincingly argues that consolation in great apes is yet another indicator that they possess a degree of consciousness, and something like a theory of mind. And by equating aspects of human behaviour with that of other great apes, de Waal also reinterprets our own behaviour, arguing that rationality plays little role in human snap decisions to act altruistically. Instead, he claims, raw, unprocessed emotion intervenes, making us more like our animal cousins than philosophers and psychologists have hitherto supposed. In principle, this hypothesis should be testable, in particular through the use of virtual environments. Indeed, all around the world video gamers may be testing it at this very minute.

The second half of Primates and Philosophers contains four commentaries, from the science writer Robert Wright and the philosophers Robert Kitcher, Christine M. Korsgaard and Peter Singer, followed by de Waal’s reply to them. In general, the commentaries dismiss “veneer theory” as “silly” and de Waal’s critique as flogging a dead horse. De Waal, however, shows that there is life in the horse yet, and that the idea still lurks in many corners of the life and social sciences. “We urgently need to move from a science that stresses narrowly selfish motives to one that considers the self as embedded in and defined by its social environment”, he concludes.

In The Evolution of Morality, the philosopher Richard Joyce covers some of the ground dealt with in Primates and Philosophers, but with a far greater degree of philosophical rigour. After explaining that he thinks the appearance of “helping behaviour” lies at the heart of the issue, he provides some strict definitions, teasing apart the nuances that separate helping, “fitness sacrificing” and altruism. The key chapter outlines his critique of the kind of position advanced by de Waal, where Joyce argues that other animals do not show any understanding of transgressions, prohibitions, or deserved punishments, all of which he argues are essential parts of morality. Joyce’s vision of the evolution of morality emphasizes instead the role of language in shaping and transmitting that set of attitudes. No language, no morality. In reply, de Waal would no doubt point both to the very real existence of punishment and policing in many animal societies, of which chimps at least seem to be very aware, and repeat his argument that language itself was a product of morality, and not the other way round. For the moment, it is difficult to see how we could devise experiments – real ones, not thought ones – that could separate these competing hypotheses. And experimentation, not argumentation, will ultimately determine which view – or neither – is correct.

Joyce’s approach is refreshing, and he wears his learning lightly: underpinning his philosophical arguments is a thorough knowledge not only of the philosophical issues, but also of the empirical and theoretical literature on various forms of natural selection and on the existence, or otherwise, of morality in animals. In general, Joyce does an excellent job of bringing philosophy to the ordinary reader, using striking and quirky examples of different moral judgements (“cleaning the toilet with the national flag is wrong”). His bold, jargon-free approach means that this work of serious philosophy can nonetheless be understood by the non-philosophically trained layperson.

The way thinkers developed the theoretical framework for understanding the evolution of social behaviour is the subject of Lee Alan Dugatkin’s The Altruism Equation. In this slim book, Dugatkin describes the work and ideas of the key figures in our understanding of the genetic bases of altruism – Charles Darwin, T. H. Huxley, Petr Kropotkin, W. C. Allee, J. B. S. Haldane, George Price and, above all, the late Bill Hamilton. The result of their work was our modern understanding of the power of “kin selection”, whereby individuals who share certain genes experience the same (positive or negative) selection pressure and, ultimately, may favour each other, in particular through “altruistic” behaviour.

In each case, Dugatkin tries to provide background material which explains some of the scientific choices made by his subjects. In the case of the anarchist Kropotkin and the socialist pacifist Allee, their emphasis on mutualistic interactions was intimately linked with their politics. But this biographical approach furnishes only limited insights, and finally fails: there is little in the outlook of the naive Stalinist Haldane, nor of the brilliant individualist Hamilton – far more interested in insects than in politics – that can easily account for the particular approach they took.

Hamilton, who was one of the greatest evolutionary biologists of the twentieth century, derived what has been called “the e = mc2 of evolutionary biology”. Hamilton’s rule, as it is known, states that altruism will evolve where the cost (c) of performing the altruistic act is less than the benefit (b) accrued to the other individual, multiplied by the degree of relatedness (r) of the two individuals. In other words, if a particular species has an ecology that leads closely related individuals to spend a great deal of time with each other, then altruism is very likely to evolve. This hypothesis is given powerful support by the example of social insects. The conditions under which genetically based altruism can evolve can be written as
rb - c > 0, a formula so simple and elegant that even the mathematically challenged can grasp the underlying biology. Dugatkin’s book covers similar scientific and biographical ground to Marek Kohn’s brilliant work A Reason for Everything: Natural selection and the English imagination (reviewed in the TLS, December 3, 2004), and Matt Ridley’s The Origins of Virtue (TLS, November 29, 1996), but Dugatkin’s results are less impressive, mainly because each chapter is so short and because too much precious space is devoted to the contrasting attitudes and experience of Kropotkin and Huxley. However, brevity is also a virtue, and interested readers (particularly students) will learn a great deal from The Altruism Equation, despite its irritating, unnecessary and repeated use of “blood kin”, which gives some pages a whiff of The Da Vinci Code’s “blood line” hokum.

One point largely missing from all three books is the development of empathy, morality, or altruism. As pointed out by the great Dutch ethologist, Niko Tinbergen, to understand a given behaviour, we need to address its proximal causes, its adaptive impact, how it evolved and how it changes with the development of the individual. In the case of human morality, this is particularly important as children show a highly developed moral sense, especially their version of “fairness”. This deeply rooted attitude may help us to understand the evolution of morality. This is not because there is a functional link between the developmental stages through which human children pass and the shaping of behaviour and morality which occurred during human evolution – Haeckel’s dictum “ontogeny recapitulates phylogeny” is not true for anatomical development, so it seems unlikely to apply to moral faculties. But there may be a relation in the other direction: the behaviour of human children may give us some insight into the behaviour of non-human organisms.

For example, in 2003, de Waal and Sarah Brosnan published an article in which they studied the responses of capuchin monkeys to what the authors termed “unequal pay”. The monkeys were trained to give the experimenter a plastic token, and in return they received a piece of food which varied from “low value” (a piece of cucumber) up to “high value” (a grape), depending on the form of the token. The monkeys were then tested in pairs, and were able to observe the outcome of the exchanges (or “work”) carried out by their partner. The situation was then manipulated, so that one monkey received food at the established exchange rate, while the other received a better “deal”, such as a grape in return for a token that only had the value of a piece of cucumber. The result was striking: the monkeys who were on lower “pay” began to stop playing the game, refusing to make the exchange, or rejecting low-value food in exchange for a low-value token. This rejection grew in amplitude if the other monkey was simply handed food without having to make any kind of exchange. The monkeys apparently knew what was expected of them, and would not participate if someone else was doing better out of the system. They wanted everyone to play by the same rules.

Both Frans de Waal and Philip Kitcher argue that this striking finding did not reveal a fully developed sense of “fairness”, because only the deprived monkeys protested against unequal treatment. Privileged monkeys seemed to be quite content with the situation. This misses the point. Firstly, almost all real human protests against unfairness involve the exploited and deprived, rather than the privileged and the wealthy (for some reason the latter do not let any such sentiments – if they have them – drive them to action). More importantly, the response of the monkeys strikes a chord in any parent who has had to deal with two young children, one of whom will inevitably wail that a particular decision is “not fair” if they do not receive the same treatment as their brother or sister. Only rarely do favoured children take up the case of their deprived siblings; like capuchin monkeys, they are, however, extremely sensitive to a decline in their own circumstances relative to other individuals. This is not surprising – we are, after all, primates.

A related point, which is touched upon by Richard Joyce, and which could produce a great deal of fruitful research, is how morality is transmitted in humans or, potentially, in other great apes. There is no “morality gene”: that much is certain. But morality might be “in” the genome, in that it emerges from the activity of a particular set of neurons, which in turn are created by a complex series of genetic and developmental interactions (including those with the environment), much as language is “in” our genes. Or it may simply be part of the social structure, like a particular human language, and be passively assimilated through the mere fact of growing up in that environment. The fact that all human societies share certain features, such as morality, would then be explained by the fact that all human societies, like all human beings, can trace a direct lineage back to the original small band of early Africans, some 100,000 years ago. Whatever they did – speak, paint, be moral – we still do, too, through cultural transmission.

A final facet of this problem, which anchors the real differences that exist between ourselves and other animals, is that morality is also consciously, deliberately taught by humans, above all to children. This is one particular aspect of our unique teaching behaviour: unlike every other animal, as far as we know, humans teach. Teaching does not appear to be necessary for tool use (chimps manage very well by copying), nor for language (babies just listen and babble), but it may be essential for transmitting values. For a true definition of what it is to be human, perhaps our species name should be changed to Homo didacticus. Testing these hypotheses and developing new theoretical explanations will be part of the challenge of twenty-first-century studies of human and primate behaviour. In their different ways, all of these books provide invaluable pointers and guides as to how that work could be fruitfully pursued.
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Matthew Cobb is Senior Lecturer in Animal Behaviour at the University of Manchester. His book The Egg and Sperm Race: The seventeenth-century scientists who unravelled the secrets of sex, life and growth was published last year.