Although psychological models of morality are equipped to account for some aspects and some functions of morality, the only theoretical perspective that is equipped to integrate these accounts under one overriding framework and supply a basis for refining them in gainful ways is the theory of evolution.
This, the last sentence of the last chapter of Dennis Krebs’s book (p. 274), nicely sums up the book’s main premise.
A psychodynamic perspective examines morality (and immorality) in terms of primitive, largely unconscious, competing instincts and motives; a social-learning perspective examines it in terms of the individual’s social experiences; a cognitive-developmental perspective examines it in terms of the child’s development from more concrete to more abstract ways of thinking; and an ethnographic perspective examines it in terms of cultural norms. But here, under the umbrella of evolution, Krebs can integrate, refine, and expand upon the insights of all of these perspectives. All of them have to do with the interaction of environmental experiences with the evolved human brain, which has, built into it, certain biases and predilections. Krebs provides us here with a biological foundation for thinking about all aspects of morality.
Krebs organises the book’s 20 chapters into 5 parts. Part One sets the stage by addressing the question of how morality is defined and how a neo-Darwinian evolutionary perspective can shed light on it. Parts Two, Three, and Four, which are the meat of the book, are organised to reflect the phylogenic development of human morality. Part Two, on ‘The Evolution of Primitive Prosocial Behaviors’ is concerned with aspects of morality that we largely share with other animals. It is about the evolution of deference, self-control, altruism (three chapters are devoted to this), and cooperation. Part Three, on ‘The Evolution of Uniquely Human Prosocial Behaviors’ is concerned with the special adaptations that our species underwent as we developed ways of living that required far more cooperation and dedication to the group than was required of our primate ancestors. Part Four, on ‘The Evolution of the Moral Senses,’ carries issues of morality from the behavioural realm into the mental realm. How and why did we acquire the ability to judge our own and others’ behaviour in moral terms, to think about moral principles, and to develop culturally specific moral norms? Finally, Part Five is on ‘Implications and Applications.’
An evolutionary account of any aspect of human behaviour is necessarily a functional account. Morality is an issue for us because we are social beings. We depend on one another for our survival, and so we must get along with one another. Our inclusive fitness (that is, our tendency to promote the survival and reproduction of our genes or copies of them), at any given moment, depending on circumstances, might be augmented or reduced by behaviours that help others or harm others. In Krebs’s words (p. 258): ‘The function of morality is to induce people to strive to increase their inclusive fitness in certain (moral) ways, and not in other (immoral) ways, which implies pursuing certain proximate goals in certain ways and not pursuing other proximate goals in other ways’. Elsewhere (p. 24) he points out that these moral ways include respecting legitimate authority, resisting temptations to maximise gains at others’ expense, upholding one’s groups, coordinating one’s behaviour with that of other members of the group, ensuring that those who participate in cooperative exchanges give and take their fair share, and honouring social contracts.
From this perspective, moral reasoning is rooted not in abstract principles but in concrete thoughts about real life situations. As one line of the evidence for the value of this functionalist perspective, Krebs presents findings from his own research that lead to a reinterpretation of Kohlberg’s classic stages of cognitive development. Whereas Kohlberg views advancement through the stages as a consequence of increasingly sophisticated thought from early childhood to adulthood, Krebs sees shifts in moral reasoning as dependent more on shifts in real living situations. Young children view morality in terms of punishment, rewards and self-interest (Stages 1 and 2) because they are immediately dependent on powerful adults for their survival. Adult prisoners tend to reason at these lower levels for the same reason. Older children and adolescents begin to view morality in terms of caring for others (Stage 3) and upholding social conventions (Stage 4) as they enter into peer relationships and social networks that become important for them to maintain. According to Krebs, when faced with real moral dilemmas in their real lives, almost nobody reasons at the more abstract, post-conventional, principled stages (Stages 5 and 6), as these have little to do with the kinds of problems that most people face daily or did in ancestral times.
One of the main strengths of this book—its sweeping coverage of so many ideas about morality in fewer than 300 pages—is also, in my opinion, its main weakness. In attempting to cover so much, Krebs does not devote the amount of detail, explanation, or research support to any one topic that some readers will want. Krebs writes clearly, but the narrative is broken into small sections and does not always move seamlessly from one topic to the next. It is perhaps best read as a textbook—a vehicle for gaining an overview of ideas within a very broad field or set of fields of scholarship. The ideas are well referenced for readers who want to follow up on any of them, and Krebs, to his credit, does not oversimplify, even when doing so might advance his argument. I recommend the book to anyone interested in exploring the evolutionary perspective on morality; but readers who are new to this perspective might want to work up to this book by first reading a less all-encompassing, more discursive treatment of the topic, such as Robert Wright’s The moral animal.
© 2012, Peter Gray