Moral Origins

by Christopher Boehm

  This interpretation is bolstered if we reconsider the political dynamics of group executions and the two ways that present-day foragers see to it that the executioners, who are fulfilling an important public duty, are not themselves killed by the executed deviant’s angry relatives. Briefly for now, the main way is to delegate the bad guy’s close kinsman to kill him, which is clearly not the case here. More rarely, the entire group may act as one to take him out, which jibes perfectly with what’s seen in these cave depictions. Some further speculation is possible if we consider statistically the causes for capital punishment presented in Chapter 4 in Table I.

  These three cave depictions might have shown the executions of fear-inspiring sorcerers or some other kind of bully, but we can only speculate about this. They might also have been prisoners of war, although this seems less likely. But what these depictions do tell us is that culturally modern humans were capable of killing someone they did not like, by acting in groups.

  Capital punishment episodes are relevant to the selection of genes precisely because the fitness of those being punished is so seriously disadvantaged. However, as we’ve seen ethnographic underreporting makes it difficult to come up with any precise annual rates for capital punishment among today’s mobile foragers. What we do know, however, is that, whereas the overall homicide rates for today’s LPA hunting bands actually may equal the rates in dangerous cities like Los Angeles,64 only a small (but still significant) portion of these would be capital punishment because most killings simply grow out of one-shot conflicts over women. However, prehistorically when bands needed to hold their more determined alphas in check in order to share large game, capital punishment was likely a viable and sometimes necessary option in dealing with the harder cases, and this could have profoundly affected gene pools.

  ARCHAEOLOGY AND THE EGALITARIAN TRANSITION

  Here’s a further and socially important piece of evidence on earlier meat-sharing that supports the idea that definitive, egalitarian control of large-game carcasses could have arrived about a quarter of a million years ago, rather than much earlier. Mary Stiner and two Israeli archaeological colleagues65 carefully examined the cut marks on bones from a number of large carcasses butchered by earlier archaic humans in the Middle East, which at the time could be considered a geographic extension of Africa.66 They discerned very different patterns at 400,000 BP, when acquiring large game still seems to have been a side occupation, as compared with 200,000 BP, when active pursuit of hooved prey had already been a mainstay for 50,000 years. Those 400,000-year-old cut marks were chaotic and varied, as might be expected if several people had been doing the butchering from a variety of angles with different tools and using a variety of personal cutting styles. This earlier human pattern seems fairly consistent with the chimpanzee-bonobo meat-eating scene, which is replete with competitive political dynamics and generally involves several individuals working a carcass at the same time—even though one individual is clearly in control. With these Middle Paleolithic archaic humans, the sharp stone flakes used for butchering could have made it important to share without much conflict, for if serious quarrels arose over meat, unlike today’s two Pan species the butcherers already had quickly lethal weapons in their hands.

  In contrast, at 200,000 BP the cut marks are those of a single individual assuming a single position to butcher the entire carcass. The potential implications are enormous, for this later pattern is quite reminiscent of what takes place with modern hunter-gatherers, where in effect the meat becomes a vigilant band’s common property, to be widely shared in a systematic, culturally routinized fashion that averts serious conflict.67 To avoid even tempting the more dominant individuals to make selfish inroads into this latter system, predictably the carcass is handed over to some “neutral” meat distributor who was uninvolved with the kill.68 This practice sees to it, by custom, that a successful hunter does not egoistically control the meat.

  The single-butcherer archaeological pattern at 200,000 BP certainly seems to be consistent with this modern practice, and obviously the kind of LPA sharing system we have been talking about would not work efficiently if selfish alpha individuals remained as little restrained as they were in the epoch of Ancestral Pan, or as they may have been when earlier archaic humans went at carcasses so individualistically 400,000 years ago. All of this at least fits with the idea that a decisive system of political egalitarianism needed to be imposed if earlier humans were to regularly eat large-game meat with good nutritional efficiency, and—again—do so without undue conflict when lethal weapons were available to all.

  THE MAIN HYPOTHESIS

  Here, then, is a thesis that fits any of the above scenarios. Whenever it was that human groups became militant about their egalitarianism, logically it became highly adaptive for a band’s alpha types to very carefully hold their dominance tendencies in check—and I’ve suggested that this, along with similar effects on those prone to act as thieves or cheaters, could explain how humans acquired a conscience. We may assume that these selfish “deviants” were genetically variable in their capacity for self-control. We also may assume that when these would-be meat hogs began to be punished regularly and severely, for antisocially throwing their weight around, this would have brought on group conflict at much higher levels than are seen today when alpha suppression is quite well routinized in LPA bands. As a result, with groups basically winning out over individuals, strong social selection pressures would have been at work on the genotypes of those prone to lose.

  Over time, the apelike, fear-based, ancestral version of personal self-control would have been augmented, as there appeared some kind of a protoconscience that no other animal was likely to evolve. That is my moral origins hypothesis. A question I shall not really attempt to answer is why bonobos and chimpanzees did not evolve in this same direction, given that they shared exactly the same major head starts. But the answer may lie largely in the fact that humans developed more complex social brains—or, possibly, that humans became dedicated large-game hunters.

  HOW QUICKLY DID A CONSCIENCE EVOLVE?

  Darwin believed all natural selection processes to be quite gradual and constant in doing their work, which was stimulated by gradual changes in the natural environment. However, a considered modern view is that sometimes such changes can be so radical, and sometimes so rapid, that what biologist Niles Eldredge called “punctuated equilibrium” takes place.69 This means that rates of genetic change may accelerate markedly owing to swift and major changes in the physical environment.

  With respect to conscience evolution, there’s also a social environment to consider.70 If after hunting began alpha power was still substantial and punitive sanctioning had to become intensive, then just by itself punitive social selection could have provided a new kind of punctuation. I say this not only because intensification of capital punishment would have affected fitness so profoundly, but also because preference-based social selection would have been so well “focused” by human intentions. By this I mean that this selection force would have been subject to purposeful adjustments as everyday social problems were being coped with and crises resolved. In effect, the large brains of humans could have led to persistent patterns of ecologically oriented political problem solving,71 which over the long term could have had profound genetic consequences. In being heavily cultural, these problem-solving styles could have been adjusted quite quickly, as physical or social environments changed.

  “Normal” natural selection processes require minimally about 1,000 generations (for humans, about 25,000 years would be the equivalent) to bring a new trait into existence. That’s what Edward O. Wilson told the world in 1978 when he wrote On Human Nature.72 Even if hunting large game was a relatively recent punctuation point, at which we may hypothesize that powerful social selection forces arose to purposefully favor individuals having superior self-control, there would have been plenty of time available for as profound a change as conscience origins to have taken place afterward, as
humans were heading for cultural modernity. The time frame can be estimated rather precisely. Hunting became intensive a quarter of a million years ago, whereas cultural (and moral) modernity had arrived by 45,000 years ago or perhaps a bit earlier. Minimally, this would have allowed for 7–8,000 generations of gene selection to do their work in making us moral or in finishing that job, and with present knowledge I’m proposing that this was accomplished to a very significant degree by social selection, guided by highly consistent social preferences.

  I must quickly say that with respect to our becoming altruistic, group selection, reciprocal altruism, and possibly all the other mechanisms discussed in Chapter 3 were likely to have been making contributions as well. But this is a question we will take up in Chapter 12.

  What if definitive egalitarianism had fully arrived before large-game hunting phased in? Even though this would seem to be inconsistent with the mode of butchering that Stiner identified at 400,000 BP, with archaic Homo sapiens as the large-brained actors it is not difficult to imagine that egalitarianism might have arrived sometime between about 500,000 BP and 250,000 BP, while Homo erectus cannot be ruled out. However, whenever this did take place, we may assume that thieves, cheaters, and, especially, alphas were not going away quietly; that many were killed or otherwise disadvantaged along the way; and that the human capacity for self-control was advancing as a result of all of this drastic social selection. In fact, if we look at the not-infrequent social sanctioning of LPA foragers, with their rather frequent use of capital punishment, this process may still be in operation at the level of gene selection.

  SEXUAL SELECTION AS BASIC THEORY

  Why has social selection been given such priority here in comparison to the other models of selection I just mentioned? Let’s consider Darwinian sexual selection as one very fundamental type of social selection.73 Sexual selection operates strongly enough to support traits we must view as maladaptive and “exaggerated,” such as peacock tails. They can exist because evolved patterns of decisionmaking are channeling the selection process, giving it what might be called (at least metaphorically) a special “focus.” In fact, sexual selection is very well focused by innately guided female choice. Think about all of those peahens preferring the more vigorous and fit peacocks, the ones who advertise their genetic superiority with the more magnificent multispotted tails. Consider, as well, the wide variety of energetically costly and often quite “exaggerated” male courtship displays in other species, described so well by Darwin, that cater to female choice,74 and you’ll realize that a preference-based type of selection can have such strong effects that otherwise patently quite maladaptive traits can be selected in spite of their heavy costs in fitness. Indeed, these traits are being kept in place solely because they provide such huge compensatory reproductive benefits to the chosen males during mating season. In this light, in trying to assess the obvious power of preference-based sexual selection keyed to mating displays, British geneticist Ronald Fisher long ago referred to interactive, “runaway effects.”75

  Punitive social selection is far from being identical. Common sense tells us right away, of course, that this can be a matter of being summarily executed—as opposed to receiving a satisfying sexual reward. Yet punishment, too, involves well-focused choices that also very directly affect reproductive success, for a dead would-be alpha male cannot breed. I hope that it will be possible some day to create mathematical models to take this special, group-actuated, punitive mode of selection into account more effectively. For now, however, I suggest that in helping a conscience to evolve, social selection could have acted quite strongly—strongly enough so it’s likely that our brains could easily have been redesigned to accommodate conscience functions over a period of 7–8,000 generations, and possibly much more.

  Keep in mind that punitive social selection continues to this day, both among the world’s very few remaining viable foraging societies and in any other type of society that consistently punishes deviants who fail to control themselves. And keep in mind that among foragers there’s far more to such negative social selection than capital punishment. I’ve emphasized this very dramatic type of group punishment because of the heavy costs imposed, but prehistorically lesser social sanctions in all likelihood also had ample generations to work with, and even though their immediate effects surely were weaker, they probably would have been employed much more frequently. For instance, the long-term effects of being ostracized or totally shunned by the band can mount up, and even just having a shamefully poor moral reputation can adversely affect an evolutionary actor’s marital and other partnership prospects because of reputational liabilities.

  UNIQUE PROPERTIES OF SOCIAL SELECTION

  Donald T. Campbell told us that when biological evolution takes place, the basic mechanisms involve what he called blind variation-and-selective-retention;76 he used all those hyphens to designate a single process that basically is devoid of purpose. This randomized process involves environmental pressures operating directly on the everyday phenotypes of variable individuals, with effects on gene pools and therefore on genotype. Here we’ve been concentrating on gang attacks and other group sanctions, and also as we’re about to see in more detail, reputational consequences that act as agencies of selection. These originate in social groups rather than in natural environments, so they merit some special interest.

  It’s in this context that I’ve come up with a highly specific evolutionary hypothesis: The killing, wounding, social exclusion, and social avoidance of aggressive (or cunning) deviants who do not rein in their predatory tendencies could have influenced earlier human gene pools, affected them so profoundly that a uniquely human conscience was able to evolve.

  This type of theory is not wholly novel, by any means. A small handful of other scholars have considered the possibility that punitive social selection can significantly affect gene pools, but they’ve done so in areas other than conscience. Not unsurprisingly, the original insight came from Darwin, even though the idea was not very well developed. Then forty years ago, in 1971, biologist Robert Trivers clearly identified as a selection force the “moralistic aggression” that hunter-gatherers are capable of.77 He suggested that when such aggression was turned against individuals who defaulted on reciprocating relationships, this would have reduced the frequencies of genes that made for cheating. I have included this basic idea in my model, even though the emphasis has been on bullies far more than on deceivers.

  ALEXANDER’S CONTRIBUTION

  In the late 1970s biologist Richard D. Alexander also began to discuss social selection in humans—at least partly in terms of group punishment of cheating, as Trivers did, but mainly positively, in the context of mating choice, with worthier males being favored by females.78 Alexander’s student Mary Jane West-Eberhard went on to suggest that Darwinian sexual selection was just one type of social selection,79 and she exemplified other kinds of social selection using mainly insect examples. As a biologist she continues to work at the task of broadly defining social selection as a particular type of genetic selection that stems directly from the social situations or social preferences of individuals.

  In 1987, in his important book The Biology of Moral Systems, Alexander elaborated his thoughts about how cooperative reciprocity in meat-sharing worked in hunter-gatherer bands and how the inherent altruistic traits might be selected. The main puzzle was the way hunter-gatherers shared meat without regard for who killed it, and the way their expectations were geared not to a “tit-for-tat” kind of payback, à la Trivers, but to what Alexander called a system of indirect reciprocity—an important concept that was introduced in Chapter 3. Briefly for now, this meant that others were being helped on the general assumption that “if I’m generous to someone today, someone will be generous to me in my time of need.”

  Alexander was trying to define the altruism paradox strictly in terms of the practices of hunter-gatherers, and in this indirect reciprocity he saw a major puzzle. Obviously, in such a generalized
system of giving and taking, the opportunistic free riders who took much more often than they gave would come out ahead in their personal fitness, while, conversely, the altruists who did more giving would come out with a deficit. This applied not only to the sharing of meat, but also to other beneficial behaviors, such as helping nonkin who become injured or ill or otherwise incapacitated.

  Explaining how such systems could evolve involved two types of social selection. In viewing indirect reciprocity as a kind of insurance system for all band members,80 Alexander had this to say about the role of group punishment: “Obviously, various forms of punishment, including ostracism or social shunning, can . . . be applied to individuals repeatedly observed not to reciprocate adequately or follow whatever codes of conduct may exist.”81 Alexander went on to emphasize, even more, the importance of social status or “reputation” to reproductive success. Although his main emphasis was on good reputations and their importance to cooperation, at this stage of my own argument bad reputations—and their social and genetic consequences—are of special interest for understanding conscience origins. A substandard conscience can generate not only a substandard reputation, but active punishment as well.

  PUNITIVE SOCIAL SELECTION

  Bad reputations are confirmed as community members gossip privately about the behavior of others. When groups of archaic hunters were coming down hard on their alphas, along with the thieves and cheaters in their midst, they very likely had the language skills to keep track of the deviants’ entire social histories, which meant they were able to make them pay not only for single transgressions but also for long-term patterns of malfeasance. Developing a superior conscience that could make similar cumulative calculations in adding up past social liabilities, and do so on an introspective basis that was private and accurate, helped the better equipped of these potential deviants to stay out of serious trouble. Thus, the genes involved in self-protective self-assessment and self-control could have been strongly supported by punitive social selection.