We have seen above some of the proximate mechanisms that structure and bias the flow of information from moral environments to the developing moral agent – the focus was on those mechanisms that facilitate the intergenerational transmission of moral phenotype from one generation to the next. This was one half of the feedback loop between the agent and their moral niche. The other is that in which the causal arrow flows the other way, where psychology influences and structures the moral niche.
We have already seen in chapter 1 how selection as an ultimate cause can favour the evolution of moral behaviours. Many moral capacities, norms and practices are selectively favoured because they enhance cooperation. Individual selection can operate in favour of moral behaviours in small groups. Group-level cultural evolution was necessary for the evolution of morality in large-scale groups. In each case, our moral worlds exist because of the cooperative benefits they confer. Proximate mechanisms also help determine the structure of our moral worlds, because the makeup and nature of our moral worlds is not independent of our psychology. Because biases play a central role in the transmission of moral information they also affect the structure of our moral worlds. This is a crucial point: our beliefs, desires, choices, preferences and embodiment effects have a direct effect on the transmission of specific cultural variants, which, as we have seen above, are partly constitutive of the moral phenotype.
9. I use the term “non-moral” to denote psychology that is not specific to morality.
Psychology helps determine the salience, memorability and motivations to exhibit moral information, thereby affecting the transmission of moral information between agents.
This bears upon the moral phenotypes that develop and, in turn, the patterns of behaviours that give rise to the construction of our moral worlds. Take, for example, moral norms. Those that have strong emotional content, such as protecting children from harm for example, are more salient, memorable and elicit strong motivations; they resonate with our emotional sensibilities. It is more likely they will be transmitted between agents within a population than norms that promote harming children.
Shaun Nichols (2002a) presents a persuasive account of how these effects play a role in the cultural evolution of norms. Through tracking historical patterns of social norms, he highlights just how our affective capacities bias the transmission of cultural information within cultures. According to Nichols, affect backed norms (such as those to do with harm and disgust) have a greater chance of transmission than non-affect backed norms and are therefore more likely to spread within and across generations. Because of their affective nature they are regarded as more serious, more important and easier to recall.
This biasing effect is a special case of what Boyd and Richerson (2004) call content bias, whereby individuals are motivated to adopt practices which appeal to them or those that are deemed to be most successful or advantageous. Content biases depend on the content of the information transmitted. Our affective responses operate as ‘cultural attractors’ which bias the evolution of moral norms. As Nichols explains, normal people have aversive responses to suffering in others. Norms that prohibit harming others are therefore more likely to spread through populations over time. Norms that reduce negative affect (or increase positive affect) will be more appealing to the psychologies of normal agents than norms that promote negative affect or are affectively neutral. There are good adaptive reasons why we have affective responses to suffering, and these responses can be harnessed by cultural evolution to promote cooperative behaviour. We construct our moral niche around the embodied responses of human agents.
Here we can see how the psychology of agents influences the construction of the moral niche. Moral cognitive capacities spread amongst populations via cultural group selection because they promote group cooperative behaviours. But our affective responses also create basins towards which cultural evolution will gravitate. The psychologies of agents within a population will therefore have direct effects upon the cultural structure of that
population. This will include the types of moral norms, behaviours and parenting practices which structure the child’s moral learning environment. (See Figure 6.2.) In this way, psychological biases help to ‘fix’ some of the content of moral cultural evolution.
Some products of cultural evolution will align more closely with our psychologies than others. When psychological biases are aligned with moral information, basins of attraction stabilise the propensity for that information to remain with the population.
Moral solutions to cooperative problems that are aligned with our psychology are more stable than those that are not.
We can see these types of effects in the dairy farming example encountered earlier.
Human preferences for the taste of milk provide basins of attraction which norms of dairy farming will gravitate towards. If humans found the taste of milk disgusting it is unlikely that we would have seen the cultural evolution of dairy farming and hence the spread of genes for lactase within dairy farming populations. Taste preferences help stabilise the cultural practices that evolve around them, making them more likely to be retained in a population as well as be passed on between generations. Similar effects are, I maintain, at play in the case of moral evolution.
Figure 6.2 Moral phenotypes and their influence on the moral niche