In October 2024, I had the great honour of travelling to Hamilton to give the Margo Wilson Memorial Lecture. It was fifteen years since Margo’s death. Preparing the lecture gave me the opportunity to reread and reflect on some of the classic work that Margo did with Martin Daly.
I have always thought that the work Margo and Martin did, mainly on homicide (examples here, here and here), was a high point of evolutionary approaches to human behaviour. It can still serve as something of an epitome or model for all of us. Reading it again just reinforced this opinion. Specifically, it gives us a particularly successful example of how you can bring evolutionary understanding to social science topics and be genuinely constructive; rather than just irritating people and inflaming the same old boundary hurts.
The work has not spawned as many imitators as, in my view, it should have. To my sadness some of my younger colleagues don’t even know it. I have been mulling over what makes it so good. Here I single out three felicitous elements, perhaps not the only ones, and not in in order of importance:
- They (M &M) got what social science is about, and met it where it actually is.
- They had the right roadmap for the relationship between evolution and human behaviour.
- They interacted modestly and with humility, to build bridges rather than empires.
In the rest of this post, I will unpack each of these a little.
Social science. Social science is a fundamentally epidemiological activity. I think this statement is true whether its methods are quantitative or qualitative. Many important things about human life in society show patterned variation across populations. Social scientists are mostly interested in describing those patterns of variation, understanding their consequences, and sometimes trying to understand what causes or maintains them.
Evolutionary psychologists often fail to get this. Sometimes they stress that in fact human societies are all pretty similar, made up of the same elements: conditional cooperation, status competition, sexual attraction, parental investment, kin nepotism, and so on. They thus downplay the very variation that social scientists are interested in, implying that the social scientists have exaggerated or even unhealthily fetishized the diversity.
The evolutionists are right that structures in all human societies are all made up from the same evolved-psychological palette. The universalist project of studying that palette, and the computations underlying it, is a legitimate and important one. But, just because the palette is always the same does not mean that the pictures are. The ways that societies end up varying from one another are striking, structured, and massively consequential for human wellbeing. Try bringing up daughters in Denmark rather than Afghanistan (or Denmark versus the USA, actually). It makes perfect sense that whole branches of human knowledge should be dedicated to understanding this variation.
Social science is not, then, a competitor activity to the explanatory project of unravelling the universal structure of the human mind. It is a different one. Whence, the persistence of social science and scientific psychology as separate endeavours for many decades. Some evolutionist critics have, I believe, simply failed to get what the typical explanatory programme of social science is. They treat it as a kind of alternative (and bad) account of the mind. In the process, they accuse social scientists of being antediluvian or unscientific, or being obtusely wedded to a ‘standard’ set of (false) causal commitments. This is absurd. Social science is a pluralistic endeavour. Many social scientists are committed to scientific methods of hypothesis testing. There is no ‘standard social science model’, still less one that can be shown to be wrong by modern psychology.
I believe – as M & M did, and as probably you do too – that the universal project of understanding the evolved mind can help, a lot, with the epidemiological project of understanding how and why social life differs across populations. But, the burden of proof is on us to show how and why this is so, through careful empirical examples that actually butter some parsnips. M &M’s stroke of genius (I believe it was Margo’s) was to realise that homicide was a great model case for such an integrative study. When one person does something as extreme as intentionally killing another, psychological mechanisms are obviously the causal drivers. But, the phenomenon has a very clear epidemiological distribution: as M & M famously showed, the homicide rate in one Chicago neighbourhood can be 100 times higher than the rate in another neighbourhood just a few miles away. Homicide varies in patterned ways across populations, across time, across social classes, and across demographic subgroups.
M & M demonstrated that epidemiological differences in homicide distribution can be fruitfully understood as arising from the interaction between local socioecological factors and evolved individual minds; minds that have a particular set of emotional responses and decision-making tendencies. This conception led to new questions to ask, new hypotheses, and in the end, more variance explained. It made for new and better social science, not an elimination of social science. Those papers are cited in sociology and criminology as much as in evolutionary psychology.
Roadmap. We might all agree that there must be some relationship between evolution by natural selection, on the one hand, and observed patterns of human behaviour and cognition on the other. However, even evolutionists don’t agree among themselves on the roadmap for getting from the one to the other.
M & M’s roadmap was an indirect one, with two key causal/explanatory links in it. The first is from natural selection to psychological adaptations. Humans have cognitive and motivational mechanisms that were shaped by natural selection to address challenges of survival and reproduction. The second link goes from psychological adaptations to manifest behaviour. It assumes that the said psychological adaptations produce behaviour by taking a read from their local socioecology, and adjusting behaviour appropriately, in view of their evolved principles. What explains behaviour is the way that the universal psychology responds to the local ecology that it finds itself in. What explains the universal psychology is (at least in part) natural selection. But, there is no direct link between natural selection and the manifest behaviour.
Under this two-step proposal, social scientists were right all along that the difference making factors between, say, a high and low homicide population are socioecological. But (step two) we won’t have much purchase on why people respond to socioecological factors in the ways they do other than by understanding the evolved mind.
I think this two-step roadmap (roadmap A), is the most useful one for most contemporary social science problems. What are the reasonable alternative roadmaps? One (roadmap B) tries to make a direct link between genetic natural selection and behaviour. For example, do murderers have more offspring, and does this positive selection explain why there are more murderers in some neighbourhoods in others? Are murderers increasing their inclusive fitness? This roadmap is right that there must, across a composite of human environments, have been recurrent relationships between behaviour and fitness. But in affluent societies, we are so far from the conditions under which our minds evolved, and fertility behaviour today is so far from maximising any kind of proxy of fitness, that the application of this kind of enquiry is limited. Better, for most purposes, to think of people as adaptation executors, to use Tooby and Cosmides’ phrase, than fitness maximizers.
The other alternative (roadmap C) is to assume that some kind of evolutionary dynamic directly drives manifest behaviour, but that dynamic is not (or mostly not), the evolutionary dynamic of genes. Think of ‘culture’ as its own system of inheritance, with its own variation and differential replication; perhaps these dynamics explain why homicide would be 100 times more common in one neighbourhood than another.
Roadmap C is attractive in some obvious ways. It seems compatible with the epidemiological character of social science. Humans in societies do obviously influence one another. It works well for a few specific cases. But, it also has many problems, as others before me have pointed out. It does not really grapple with the actual causal drivers of behaviour. Men don’t kill their children because they have often seen it modelled in their population, or because prestigious people do it. In fact, it is very rare or nonexistent in their cultural input, yet sometimes they do it anyway (and, systematically, under some circumstances more than under others). Sometimes people don’t do things even though those things are culturally expected; and sometimes they do things even though those things violate cultural expectation. That is what I want to explain. You can’t get very far with this kind of enquiry with a generalized tendency to conform. You need specific socioecologies interacting with a content-rich psychology. You need to model humans who have not just learning capacities, but also goals.
Where roadmap B tries to make the link between contemporary behaviour and genetic fitness too close, roadmap C makes it, for my taste, not close enough. Once we unleash a quasi-autonomous cultural process with minimal constraints, I cease to know what empirical predictions we can make. We have lost explanatory access to modern inclusive fitness theory, one of the most useful and successful paradigms of twentieth century science. We don’t have much handle on why some things but not others would be stable in some kinds of ecologies, or why and how social change happens.
In sum, roadmap C wants a pretty casual relationship between genetic inclusive fitness and contemporary human behaviour. Friends with benefits. Roadmap B wants to go all the way. Roadmap A wants to hold hands, but not go all the way. For me, that’s the right compromise. M & M got all this, before most of us had any clue what the debate was even about (here, here and here for example).
Modesty and humility. One of the most striking things about M & M’s work is the modesty and humility with which it is presented. Their papers don’t herald a Darwinian revolution that will revolutionize the social sciences. They don’t compare themselves to Galileo or Copernicus. They are certainly not shy about defending the logical grounds for their approach, or criticizing what they see as wrong directions. But this assertiveness is always specific and reasoned. They don’t dismiss social science as benighted, becalmed or misguided. They identify specific empirical puzzles and suggest explanatory resources to help solve them, invoking Darwinian principles, where relevant, clearly but without being head-bangers.
Margo was sincere about the need to understand existing social science if she was going to study homicide from an evolutionary perspective; so sincere that she took herself off to get a masters degree in legal studies, having already got a degree and doctorate in biology. She spent a great amount of time painstakingly improving the Chicago Homicide Database. There was nothing specifically ‘evolutionary’ about doing this: she was just being a good researcher, serious about making our knowledge of the world more accurate.
This sincerity did not go unnoticed. It is moving to read the special issue of the journal Homicide Studies that was published in response to Margo’s death. Several contributions from social scientists who came to know Margo make similar points. On first hearing, they say, we thought the evolutionary psychology stuff was bananas, or worse (one contribution: ‘the theoretical perspective of Evolutionary Psychology posed by Wilson and Daly constituted an allergen within the collective nose of the social sciences’; another, ‘convincing feminist social scientists to consider the importance and relevance of evolutionary bases for male partner violence is a tough sell’). But once they saw how sincere Margo was about better understanding human violence, they could not but become at least curious, and in many cases sympathetic, to her research program. They saw that she was serious about the empirics; they came to want to understand how the explanations she was offering really worked, what they entailed and what they did not; and they appreciated Margo’s willingness to listen to their disciplinary traditions and the meanings given to concepts within them. In short, she was good at building bridges.
Surely building bridges between the social sciences and the sciences of the individual brain/mind is exactly what we need to do. Some of Margo’s success was no doubt due to her personal qualities. Everyone who knew her speaks of these. (‘Margo somehow seemed to do all of this with ease and without the overinflated ego often seen in academia. She just seemed to “leave herself and her ego behind” as she reached out and showed a genuine interest in others and their work.’) But there might be a more generalisable formula for progress there too; for evolutionary psychology and social science to encounter one another in the form of genuine dialogue, with an interest in what is we each know and don’t know; what our goals are; and how we think about them. This is much more refreshing than the all too familiar parade of – and I use the term advisedly – cocks on dunghills.