Is Morality a Gadget? Nature, Nurture and Culture in Moral Development
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Author Accepted Manuscript. To appear in a special issue of Synthese on The Cultural Evolution of Human Social Cognition, edited by Richard Moore, Rachael Brown & Cecilia Heyes. 24 July 2019 IS MORALITY A GADGET? NATURE, NURTURE AND CULTURE IN MORAL DEVELOPMENT Cecilia Heyes All Souls College & Department of Experimental Psychology University of Oxford Oxford OX1 4AL United Kingdom [email protected] 1 Abstract Research on ‘moral learning’ examines the roles of domain-general processes, such as Bayesian inference and reinforcement learning, in the development of moral beliefs and values. Alert to the power of these processes and equipped with both the analytic resources of philosophy and the empirical methods of psychology, ‘moral learners’ are ideally placed to discover the contributions of nature, nurture and culture to moral development. However, I argue that to achieve these objectives research on moral learning needs to 1) overcome nativist bias, and 2) distinguish two kinds of social learning: learning from and learning about. An agent learns from others when there is transfer of competence - what the learner learns is similar to, and causally dependent on, what the model knows. When an agent learns about the social world there is no transfer of competence - observable features of other agents are just the content of what-is-learned. Learning from does not require explicit instruction. A novice can learn from an expert who is ‘leaking’ her morality in the form of emotionally charged behaviour or involuntary use of vocabulary. To the extent that moral development depends on learning from other agents, there is the potential for cultural selection of moral beliefs and values. Keywords: Cultural evolution; social learning; moral psychology; moral learning; moral development; nativism. 2 Moral psychology - a field in which philosophers are at least as prominent as psychologists - is growing exponentially (Priva and Austerweil 2015). Some would say it is blossoming, others that it is spreading like a weed, but even detractors must admit that, since it emerged 15-20 years ago, moral psychology has told us a great deal about what people consider to be wrong, the types of psychological and neurobiological mechanisms involved in making moral judgements, and where those mechanisms come from (Cushman, Kumar & Railton 2017). This article focusses on the last of these issues, on questions about moral development. I am enthusiastic about moral psychology as an interdisciplinary enterprise but I worry about the way it is tackling moral development. Moral psychology seems to be proceeding as if human psychological development draws on just two sources of information, nature and nurture, when in fact it draws on three – nature, nurture, and culture (Heyes 2018a; Shea 2012). I use ‘nature’ to refer to genetic contributions to development - information about the environment obtained by natural selection and carried by DNA sequences. ‘Nurture’ contributes to the extent that development depends on information about the environment obtained by direct interaction between the developing system and the world in which it is developing. ‘Culture’ plays a role to the extent that development of a characteristic (morphological, physiological, or psychological) depends on social inheritance – information that is passed from one generation to the next, not via DNA sequences, but via social interaction (Lewens 2015). Understood in this way, as socially inherited information, culture is like nature in contributing inherited information to development, and like nurture in its dependence on learning. However, culture is different from nature in depending on social rather than genetic inheritance, and different from nurture in depending on a special kind of learning, ‘cultural learning’. Cultural learning has been characterised in a variety of ways (e.g. Tomasello, Kruger and Ratner 1993). In this article I suggest that it is helpful to think of cultural learning as learning from other agents. What is culturally learned from other agents can be about other agents or the inanimate world. Viewed in this way, cultural learning contrasts with learning about other agents or the inanimate world in a way that does not involve transfer of information from other agents. The alternative to cultural learning, which is part of nurture’s contributions to development, is sometimes characterised as ‘trial-and-error’ learning or, as in the preceding paragraph, as learning by ‘direct interaction’ with the social or asocial environment. An agent can acquire through cultural learning information she could not gain through her own efforts. For example, children in West Africa learn from adults how to ‘wet’ or ferment bitter manioc (cassava) so that it provides a safe and plentiful source of starch in the diet. The process, which detoxifies manioc, has several stages involving scraping, grating, washing and boiling. If 3 novices relied not on cultural learning but instead on solitary trial-and-error learning - direct interaction with manioc – they would almost certainly die of cyanide poisoning before finding a safe method of preparation (Henrich 2015; Rozin 1988). Notice that ‘culture’ is not always used, as it is here, to refer to socially inherited information. ‘Culture’ is often understood to refer to attributes that vary between social groups. Of course, both of these uses are legitimate, but I shall argue that problems arise when they are conflated. Socially inherited information can, but does not invariably, give rise to differences between social groups, and differences between social groups are not always due to socially inherited information. Both nature and nurture contribute to the development of all biological characteristics in all organisms. There are no pure cases in which nature alone, or nurture alone, is responsible for mature form. Some characteristics, mostly found in humans, have a third ingredient, culture; their development also depends on socially inherited information. Since the 1980s research on ‘cultural evolution’ has shown through field work, mathematical modelling, and laboratory experiments that socially inherited information plays a dominant role in the development of many of our tools and technical skills, such as manioc processing, and in the development of our explicit beliefs and preferences, such as the preference for a large or small family (Campbell 1965; Cavalli-Sforza & Feldman 1981; Henrich 2015; Richerson and Boyd 2005). Recently I argued that distinctively human cognitive processes – such as language, mindreading, and imitation – are also products of socially inherited information. I suggested that, rather than being ‘cognitive instincts’ (Pinker 2003), distinctively human cognitive processes are ‘cognitive gadgets’; they are constructed in the course of development, through social interaction, from old, genetically inherited parts, and ‘designed’ by selection operating on cultural rather than genetic variants (Heyes 2018a). Unlike some other distinctively human cognitive processes, morality may not involve dedicated, computationally distinctive psychological mechanisms (Greene 2015). However, morality certainly involves distinctive beliefs and preferences; judgements and intuitions about what is and is not right, about how people should and should not behave. Therefore, the recent rapid growth in understanding of cultural evolution (Youngblood & Lahti 2018) raises a fundamental question (Sterelny 2010): How important is socially inherited information in the development of morality? Or, to put it another way, is morality a gadget? To the extent that the development of morality depends on socially inherited information, there is the potential for cultural selection - the potential for morality to become adaptive, good at doing its job, through cultural rather than genetic evolution. About a year ago I began to immerse myself in the literature on moral psychology hoping to find out whether morality is a gadget. So far, I have failed. Maybe I’ve been obtuse or looking in the 4 wrong places, but I suspect there are (also) three more interesting reasons: 1) Moral psychology has a nativist bias. In spite of a recent surge of interest in ‘moral learning’ (Cushman, Kumar & Railton 2017; Railton 2017), most moral psychologists continue to be preoccupied by nature’s contributions to the development of morality. 2) When one is trying to trace sources of information about the social environment it is difficult to distinguish nurture from culture; to keep apart cases in which the child learns about other people and cases in which she learns from other people. 3) Research on moral learning has the potential to overcome both of these problems but to do so it would need not only to overcome nativist bias and distinguish more clearly between learning about and learning from others, but also to take more interest in the opportunities for learning experienced by children in their everyday lives. Modelling and laboratory experiments can tell us how morality could possibly be learned, but unless these methods are combined with naturalistic observation they cannot tell us how morality is actually learned. I will discuss each of these three issues in turn. 1. Nativism in moral psychology Moral psychology has been influenced greatly by what Fodor (2001) called “High Church evolutionary psychology”. This is the project, most closely associated with the work of Cosmides and Tooby (1994) and Pinker (2003), that casts the human mind as a