Wednesday, November 21, 2012

Christopher Boehm, Moral Origins, The Evolution of Virtue, Altruism, and Shame (2012)

Anthropologist Christopher Boehm is interested in this question:  Why did humans evolve a conscience?  Before exploring this question and what Boehm believes may be the answer to his question, I want to develop some facts and opinions of others on issues that I believe bear on this question, some of which Boehm does discuss and some of which he does not discuss in his book Moral Origins.

The first issue I want to address is the role of emotions, and in particular the social emotions in the origins of human morality.  Boehm concludes Moral Origins by saying that in a few generations we "may have identified some of the genetic mechanisms that help us to behave egoistically, nepotistically, and altruistically, along with others that make for sympathetic generosity, domination and submission, and a variety of other socially significant behaviors that are relevant to morality, including our shame responses."  Boehm may well be right that we will identify the genetic mechanisms behind moral and immoral behavior in a few generations, but the roadmap of investigation is already before us and it begins with emotions.  I say this for two reasons:  first, if anything, genes code for our body chemistry; genes may or may not code for specific behavior (moral or otherwise), although I doubt it (see November 30, 2009 post).  But emotions are driven by electro-chemical actions and reactions in our various body systems and ultimately the neurological system leading to our brains, and genes do code for these electro-chemical actions and reactions and genes code for our brain and other body organs.  If we want to understand the genetic basis for moral and immoral behavior we will look for the genes tied to these body systems and the chemistry that drives emotions.  The second reason is not biological, but an observation that philosophers have made since the 18th century: that emotions, and in particular certain social emotions shape our "moral sentiments." (See April 8, 2011 post).  I am thinking particularly of David Hume (see February 27, 2011 post)  and Adam Smith (see January 11, 2011 post).  Research is beginning to show that emotions trigger moral behavior. 

The second issue is the growth of the brain in the evolution of hominids leading to homo sapiens.  Antonio Damasio's works confirm that the evolution of consciousness in humans is tied to the growth and development of the brain, particularly the cortical regions, and without "extended" consciousness apparently enabled by the larger human brain we very likely have no conscience.  (See April 8, 2011 post and October 25, 2011 post).  Damasio hits a theme in these two paragraphs from his book, Looking for Spinoza, that I quote at length below, and which I don't believe Boehm would disagree with:

"The construction of what we call ethics in humans may have begun as part of an overall program of bioregulation.  The embryo of ethical behaviors would have been another step in a progression that includes all the nonconscious, automated mechanisms that provide metabolic regulation; drives and motivations; emotions of diverse kinds; and feelings.   Most importantly, the situations that evoke these emotions and feelings call for solutions that include cooperation.  It is not difficult to imagine the emergence of justice and honor out of the practices of cooperation.  Yet another layer of social emotions, expressed in the form of dominant or submissive behaviors within the group, would have played an important role in the active give and take that define cooperation.

"It is reasonable to believe that humans equipped with this repertoire of emotions and whose personality traits include cooperative strategies would be more likely to survive longer and leave more descendants.  That would have been the way to establish a genomic basis for brains capable of producing cooperative behavior.  This is not to suggest that there is a gene for cooperative behavior, let alone ethical behavior in general.  All that would be necessary would be a consistent presence of the many genes likely to endow brains with certain regions of circuitry and with the attendant wiring --- for example, regions such as the ventromedial frontal lobe that can interrelate certain categories of perceived events with certain emotional feeling responses.  In other words, some genes working in concert would promote the construction of certain brain components, and the regular operation of those components, which, in turn, given the appropriate environmental exposures, would make certain kinds of cognitive strategy and behavior more probable under certain circumstances.  In essence, evolution would have endowed brains with the apparatus necessary to recognize certain cognitive configurations and trigger certain emotions related to the management of the problems or opportunities posed by those configurations.  The fine tuning of that remarkable apparatus would depend on the history and habitat of the developing organism." (emphasis added).

The social emotions: Shame, Sympathy and Empathy. The so-called "social emotions" --- embarrassment, guilt, shame, and pride --- are linked to moral behavior in humans, and therefore no discussion of moral origins can ignore social emotions. "It is highly probable that the availability of such social emotions has played a role in the development of complex cultural mechanisms of social regulation," writes Antonio Damasio in Looking for Spinoza. "It is also apparent that some social emotional reactions are elicited in human social situations without the stimulus for the reaction being apparent to the reactor and to observers." Damasio believes that the social emotions are buried deep in the organism's brain, innate rather than taught. (See April 8, 2011 post). Researchers have concluded that social emotions are not unique to humans. As Damasio observed in Looking for Spinoza, "Because the term 'social' inevitably conjures up the notion of human society and of culture, it is important to note that social emotions are by no means confined to humans. Look around and you will find examples of social emotions in chimpanzees, baboons, and plain monkeys; in dolphins and lions; in wolves; and, of course, in your dog and cat. The examples abound --- the proud ambulations of a dominant monkey; the literally regal deportment of a dominant great ape or wolf that commands the respect of the group; the humiliated behavior of the animal that does not dominate an must yield space and precedence at mealtimes; the sympathy an elephant shows toward another that is injured and ailing; or the embarrassment the dog shows after doing what he should not." (See also June 17, 2010 post).

Psychologists distinguish between basic emotions and social emotions.  Moral emotions are treated as a subset of social emotions.  Which emotions constitute the "basic" emotions is a matter of debate, but they at least include happiness, sadness, disgust, anger, and fear --- emotions that require an awareness of one's own somatic state.  These are ancient emotions that are tied to survival, driving us away from harm and directing us toward some reward.  Social emotions require the existence of a group, a theory of mind (TOM) and an awareness of the mental states of others.  The social emotions include embarrassment, guilt, shame, contempt, indignation, sympathy, compassion, gratitude and pride.  Following Jonathan Haidt's paper on The Moral Emotions, Antonio Damasio in Looking for Spinoza has described the basic emotions underlying the social emotions and what he calls the emotionally competent stimulus (ECS) for and consequences of the social emotions as follows:

Social emotion
Basic emotion
Embarrassment, shame, guilt
Weakness or failure or violation in individual’s own behavior
Prevent or avoid punishment by others; restore balance to self or group
Fear, sadness
Contempt, indignation
Other individual’s violation of norms
Punishment or violation, enforcing of social norms
Disgust, anger
Sympathy, compassion
Another individual suffering, in need
Comfort, restoration of balance in other or group
Attachment, sadness
Awe, gratitude, pride
Recognition in others or self of contribution to cooperation
Reward for cooperation, reinforcing tendency to cooperate

These social emotions, the ECS, and consequences become central to Boehm's discussion of moral origins.  Damasio's point:  "In a society deprived of such emotions and feelings, there would have been no spontaneous exhibition of the innate social response that foreshadow a simple ethical system---no budding altruism, no kindness when kindness is due, no censure when censure is appropriate, no automatic sense of one's own failings.  In he absence of the feelings or such emotions, humans would not have engaged in a negotiation aimed at finding solutions for problems faced by the group, e.g., identification and sharing of food resources, defense against threats or disputes among its members."  Boehm at least implicitly recognizes this in the subtitle of his book --- The Evolution of Virtue, Altruism and Shame --- but the genetic foundations of our emotions is not clearly called out.

Shame is particularly called out by Boehm as an emotion central to moral origins in humans, but I will address that more specifically later.  Boehm repeatedly treats sympathy and empathy as synonyms; they are not and I want to comment on that here.  But in discussing moral origins, Boehm is correct to emphasize "sympathy."  Sympathy, as Damasio's categories above suggest, is proactive: the consequence is for one person to provide comfort to another person.  As Frans DeWaal says in The Age of Empathy (see November 9, 2010 post), "Sympathy, in contrast, reflects concern about the other and a desire to improve the other's situation."  In contrast, "Empathy is the process by which we gather information about someone else."  Empathy is more of a feeling rather than an emotion.  As Jonathan Haidt writes in his article The Moral Emotions,  "Empathy is not an emotion at all; it is a tendency to feel whatever another person is feeling, including happiness, anger, or boredom."  With respect to empathy, we can recall the discussion of mirror neurons in monkeys, apes, and humans, that would facilitate these feelings.  (See October 25, 2011 post and July 16, 2010 post)  "Empathy is easily aroused," says DeWaal, but "sympathy is anything but automatic."  Sympathy is common in both humans, chimpanzees and bonobos who can be consoling.  Sympathy, however, would not occur without a capacity for empathy. 

This brings us to shame, embarrassment and guilt. Shame attracted the attention of Charles Darwin. He noted that humans universally blushed with shame that appeared to be associated with a moral conscience. This behavior is seen only in humans. By definition, shame is provoked when an individual recognizes that his or her own conduct (or perhaps the conduct of another group member, for example shame due to the conduct of one's own child or spouse) has transgressed the social rules or expectations of others.  Shame implicitly, if not explicitly, acknowledges the applicability of those social rules to one's own conduct.  It is similar to guilt, but guilt could apply to an individual's own rules and not merely social rules.  Boehm says that during his research in the African forest "the apes never appeared to me as though they were upset over their own behavior, let alone ashamed of it or remorseful. I did notice that between individuals there were postures and gestures that seemed to ask for or grant forgiveness, and in fact chimpanzees often make up after conflicts. . . However, this seems to be aimed merely at reducing tension or restoring positive relations, so reading a morally-based element of remorse into such behavior would be patently anthropocentric. Nothing I observed ever convinced me that there was something like morally based self-recrimination in the wild, for aggressors never appeared to be troubled by their actions afterward." How did humans come to blush with shame so predictably, asks Boehm? Much of the answer has to lie in biology, he says, but in considering actual selection process that might have supported the existence of a conscience Boehm's social selection' theory described above "explains the rather unusual set of agencies that created this moral faculty for us." Once shame feelings emerged "there would have been no question about [humans] moral status, reflecting that humans had strongly internalized group values and a sense of right and wrong," concluded Boehm. The expression of shame, guilt, and embarrassment enables the deviant to avoid punishment by others and restores one's place in the group.  But was the environmental trigger that induced the expression of the shame emotion in humans the behavior of other humans?  Although he does not expressly say this, Boehm's "social selection" theory seems to suggest this.

What we are ultimately interested in here is the development of altruistic behavior: direct and indirect reciprocal behavior (see September 27, 2012 post and September 12, 2012 post) in terms of the consequences described in Damasio's categories above, cooperation. What were the environmental drivers that triggered the development of moral emotions and ultimately the capacity to engage in altruistic reciprocal exchange, particularly that exchange that does not require direct reciprocal exchange?  As Martin Nowak observed in Supercooperators, "We are the only species that "can summon the full power of indirect reciprocity, thanks to our rich and flexible language."  (See September 17, 2012 post).

Human brain size and structure.  While the social insects demonstrate that cooperation is not a function of brain size (see November 4, 2009 post) , in hominids, I submit, it is highly relevant. Also relevant, according to recent research, are variations between species in the relative size of certain areas of this larger brain and the extent of interconnections between areas that can explain differences in temperament and behavior that translates into greater empathy and less aggression, which may or may not have co-evolved with the enlargement of the brain.  Also relevant may be differences in neurons between species.  (See November 9, 2010 post).  Boehm also believes this subject is relevant to his inquiry about the evolution of conscience, but he is not certain just how much weight to assign to his answer. According to Lynch and Granger in their book Big Brain, the chimpanzee has a brain size roughly 350-400 cubic centimeters (cc); the extinct Australopithecus, a brain size of about 440-450cc; extinct homo habilis, a brain size of about 600cc; the extinct homo erectus, a brain size of about 800cc-1000cc; the extinct homo heidelbergensis, a brain size of about 1200cc; the extinct neanderthal (homo neanderthalensis), a brain size of about 1500cc; and homo sapiens, a brain size of about 1350cc. In the evolutionary trail from the genus pan to the genus homo and the species within the genus homo, the brain enlarged over time (although the human brain has apparently shrunk in more modern times). The pan/homo divergence is believed to have occurred about 6 million years ago, and an emergent characteristic of the new species was bipedalism --- upright walking - which evolved with austalopithecines, perhaps as early as 3.6 million years ago, long before larger brain size. According to Lynch and Granger, changes to body that support walking increased lower trunk, and a side effect of a longer, lower trunk is to increase the space into which a uterus can expand during pregnancy. In women, this is accompanied by a wider pelvic girdle and the result is bigger babies. Bigger brains follows bigger babies. As the brain becomes bigger, most of the increase is not dedicated to sensory and motor needs, but to new neocortical areas. The biggest brains have much more cortex than smaller brains, and moreover, a bigger cortex has within it much more association cortex than sensory regions. This results in different relative intelligence for different brain size. Natural selection, conclude Lynch and Granger, did not select for intelligence. Intelligence was enabled by larger brains. Intelligence has been enabled by an expanded neocortex, which in humans is involved in higher functions such as sensory perception, generation of motor commands, spatial reasoning, conscious thought and language. The neanderthal evolved roughly 200-250,000 years ago in Europe and Asia; the homo sapien approximately 150-200,000 years ago in Africa. These capabilities of larger brains in homo sapiens did not emerge immediately. Language, for example, is not believed to have emerged until roughly 100,000 years ago. Language, I believe, is crucial for the evolution of a conscience, and Boehm appears to agree ("Morality is a group affair . . . Critical to this process is talking . . .").  Proto-languages, however, may have existed with earlier species such as homo erectus, but we will never know.  Equally critical to cooperative behavior in my view, particularly because it must be tied to indirect reciprocity, is the development of long-term memory, which is said to be encoded in the medial temporal lobe

As Antonio Damasio described above, parts of the prefrontal cortex are significant to social emotional associations, decision-making and moderating social behavior. Studies show that damage to a part of the ventromedial prefrontal cortex can impair empathetic responses in humans.  While other pan species have a prefrontal cortex, the prefrontal cortex of the human brain is significantly larger than that of chimpanzees, bonobos, and other apes, it also has more substantial folding (hence greater surface area) in this area than chimps and apes, and this has significant implications for behavioral differences that distinguish chimpanzees from humans.  Since we have seen that sympathy and empathy have been observed in the pan species, chimpanzees and bonobos, and that these species have prefrontal cortex structures similar, but not identical to humans, the human capacity for empathy and sympathy has its origins long ago in our non-human ancestors.  The larger brain capacity in homo, it is my belief, together with relative enlargement of certain areas of the brain and the connections between them, has probably contributed to their greater ability to engage in self-control over their egotistical impulses and greater empathy and compassion for other humans and perhaps other animals.  What we don't possess at this time is much in the way of research on the neural correlates of shame and guilt.  An Internet search came across only a couple of recent papers that acknowledged there had not been much research in this area, and that research might advance this discussion a bit.

Selfish or self-control?  In a prior post discussing Richard Wrangham's Demonic Males (see July 1, 2010 post), I noted, "If this was the only book one read on the subject of the origins of human behavior, you would conclude that male humans are born to kill, but empirical observation tells us that is not the only truism one can declare about male humans. Demonic Males is very interesting for what it documents: the apparent origins of human violence can be found in other primate species closest to humans, which indicates a genetic and evolutionary foundation for violent behavior among human males. But there is more to the story that primatologists are telling us about the commonalities among primate behaviors, including the origins of social cohesion, cooperation, and even morality and altruism. Michael Gazzaniga's Human (September 27, 2009 post) contributes much to this broader understanding of human evolution. Wrangham barely mentions these other common attributes of primate social systems. Violence is only one behavioral aspect of our social nature."  Boehm would agree that humans are very different than chimpanzees, and what he endeavors to explain in Moral Origins is that notwithstanding the fact that selfish, egoistic impulses are stronger in humans than altruistic impulses, humans have evolved a capacity for self-control that suppresses selfishness and campaigns for generosity and the Golden Rule. Boehm falls in the line of thinkers that includes Frans DeWaal and repeatedly emphasizes our dual nature:  we are selfish egoists and we are selfless altruists.  As I described in the post discussing DeWaal's The Age Empathy (see November 9, 2010 post),   "DeWaal takes aim at three myths: (1) the myth that our ancestors --- 4 foot bipedal apes --- ruled the savanna in Africa; (2) that human society is a voluntary creation of autonomous men; and (3) that our species has been waging war for as long as it has been around. Our ancestors were likely both prey and predator and survival favored genes that encouraged collaboration and companionship. The idea that humans were autonomous falsely presumes they had no need for anybody else and could voluntarily choose to live apart, uncommitted to anyone else or any place. A warlike initial state of nature that philosophers like Rousseau imagined that was overcome by social compacts is actually the reverse of human evolution: war on a grand scale, like we have known for centuries, came only after social hierarchies were formed and wealth was created. The early human species was probably defined more by social commitments and small scale collaboration that promoted primitive economic exchange and division of labor."  Moral Origins is an attempt to provide a historical account of how these social commitments and small scale collaboration evolved. 

Fire and group behavior.  Recall E.O. Wilson's view that a key event (but certainly not the only event) in the development of human eusociality was the mastery of fire.  (See September 12, 2012 post).  The nest, or its equivalent, is viewed by Wilson as a key to eusociality, and the campfire, according to Wilson, is the human equivalent of a nest found in other eusocial species.  For genus homomastery of fire occurred first during the era of homo erectus, perhaps as early as one million years ago but certainly 600-800,000 years ago, and long before the emergence of homo sapiens and homo neanderthalensis 200,000 years ago.  The development and use of early tools is also associated with homo erectus, and homo erectus may have lived in small bands of 30-50 men and womenWhat we do not know is whether homo erectus' ability to control fire was merely the use of fire otherwise started naturally, or resulted in the development of a campfire created by homo erectus --- the equivalent of the nest in other eusocial species.  There is a debate as to whether or not homo erectus had vocal communications ability.   But clearly we can see in this species some of the precursors of human eusociality that both Wilson (September 12, 2012 post) and Martin Nowak (see September 17, 2012 post) addressed. 

The campfire is not merely a nest but it is a location where food, particularly protein-rich meat is cooked and consumed.  This is significant for the larger-brain hominid described above.  Recent studies indicate that increased consumption of cooked vegetation and meat supports larger brains.  The larger brain is not, as described above, merely defined in terms of cranial capacity, but greater neuronal capacity ("neuron rich").  If larger hominids had larger brains, as Lynch and Granger posit, it is plausible that the more successful ("fit") of these larger hominids would put these larger brains to better use than other hominids.  The brain with greater neuronal connections to other parts of the brain and increased neuronal capacity is more likely to do that, and to support those connections and neurons requires increased consumption of cooked vegetation and meat to meet the energy demands of that brain.  It is also plausible that the larger hominid with the larger brain would have to kill larger animals and consume them more frequently than the chimpanzee and other apes and hominids, and to accomplish that feat it is plausible that hunting, killing, and cooking meat in groups is a more successful ("fit") strategy.  To incent that group behavior and longer-term group cohesion for capturing and killing large animals, it is plausible that sharing meat in the vicinity of the campfire would enhance success/survival ("fitness").  Thus, the campfire and brain size are plausibly linked to survival of the hominid phenotype. 

Christopher Boehm notes that most other researchers have taken an ahistorical approach to moral origins among humans, focusing as does E.O. Wilson (September 12, 2012 post) on evolutionary theory as applied to kin selection and group selection or, as does Martin Nowak,(September 17, 2012 post) on mathematical fitness estimations for conditions favoring reciprocal behavior. Boehm offers a historical approach, but to his own credit he, like Charles Darwin, admits to the difficulties in this approach:  we have no written record from the pan troglodytes of 3-6 million years ago, or the austalopethicines of 3.5 million years or the homo habilis or the homo erectus, or even the more recent homo neanderthalensis that followed, about how these extinct species interacted socially (the extent of their within group or other group competition or cooperation), how they communicated.  Furthermore, we have a sketchy, but growing fossil record of these now extinct species, but the fossil record tells us no more about the organization of the brains of these species; all we know is their cranial capacity.  What we do have is evidence of fires, markings on bones, shaped rocks that indicates their use as tools or hunting devices found in the vicinity of the remains of these extinct species and capable of carbon dating, as well as the bones of animals nearby indicating that humans or their predecessors consumed the meat of these animals.  These are true challenges for developing a historical record of what these extinct species were actually like, and Boehm, like Darwin, is forced to describe a history based on its "general plausibility" by providing a working hypothesis, some of which are no more than "glorified hunches, while others may seem them as highly worthwhile leads for future research." 

In addition to the sketchy fossil record described above, Boehm also has at his disposal a body of evidence that can be observed today that is relevant to developing his history:  chimpanzee and bonobo behavior that is presumably similar to their behavior 6 million years ago when the ancestors of genus homo split from pan troglodytes, and the recorded observations of scholars about these species are growing; furthermore, we have a record of observations about a dwindling number of  homo sapiens hunter-gatherer groups developed over the past century to the current period, which behavior is presumably not much different than homo sapiens hunter gatherers who existed 35,000 to perhaps 200,000 years ago.  Based on these observations, Boehm concludes that human hunter gatherers, both now and then, exhibit a behavior that is distinctly different than the behavior of our closest relative, the chimpanzee.  Whereas, the male chimpanzee, is obsessed with dominance and rank and lives in social groups organized hierarchically led by an "alpha male," often displaying in-group aggression against one another and instability in rank, and female chimpanzees less obsessed with rank and dominance, less social, and less aggressive than their male counterparts, the human hunter gatherer of the late Pleistocene, based on modern observations, is characterized by egalitarian relations among persons within small groups, says Boehm.  Something happened in the evolution of the genus pan, to the australopethicines, and genus homo over the 5.8 million year period from the time of split and the emergence of homo sapiens about 200,000 years ago that transformed one species from a hierarchical dominance obsessed social group marked by within group aggression to another species characterized by within-group egalitarianism.  That is the historical trail Boehm seeks to describe in discovering how humans developed a conscience, whereby humans internalize group rules. 

Boehm believes there is a special type of natural selection that he calls "social selection" that involves "the effects of human preferences in choosing others in useful partnerships or in coming down hard on disliked deviants [cheaters]."  His working hypothesis is that at some point in the course of human history, group punishment of cheaters became severe and frequent and affected the human gene pool and ultimately favored human individuals with greater self-control in order to avoid group punishment. Group punishment could have been lethal, Boehm surmises, but it could have involved ostracism or deprivation of what was treated as community property, notably meat.  Whatever the form of punishment invites submissiveness to the group.  The "instrument" of self-control, believes Boehm, is the conscience.  What triggered this development, he submits, is humans embarking on a "new kind of subsistence pattern based on hunting" large animals for food that could only be met by groups.  For these groups to have any kind cohesion required an efficient, equitable sharing of the meat of these large animals.  The obstacle to setting up this egalitarian scenario for a small band of human hunters, Boehm recognizes, is the nature of the ancestral alpha male prone to appropriating the meat of others, which has not altogether disappeared from human nature today.  To achieve egalitarian relations among a small group of human hunters required the threat of force, enforced by the small group.  He believes that this evolutionary trend began around 200-250,000 years ago and culminated approximately 45,000 years ago.  He says this is a "tentative hypothesis," and new archaeological finds and future developments in behavioral genetics could lead to alternative hypotheses. 

Boehm suspects that the step from hierarchically-organized rank-oriented aggressive chimpanzees to egalitarian human hunter-gatherers was motivated by "rank-and-file envy over the perks of alpha bullies, which related to power, food, and sex."  In other words, at some point in time a few million years ago along the trail to homo sapiens, the submissive gradually said we have had enough, we are tired of being intimidated.  The submissive "would have developed some systematic type of collectivized and potentially lethal social control . . . to prevent high-ranking bullies from just naturally monopolizing large carcasses killed by group members and acting as free-riders, when it was the undernourished others in the band who were doing the hard work of hunting."  This type of social sanctioning is observed in modern human hunter gatherer groups in the modern era.  The alpha males are compelled to adapt to the group's will by achieving greater self-control over their egoistic impulses in order to gain greater fitness.  Boehm admits that it is possible that the evolution to egalitarianism began earlier than 200-250,000 years ago when homo sapiens first appeared on the scene (e.g. during the era of homo erectus as early as 1.8 million years ago), but at this point this is even more speculative than the plausible scenario found in the human fossil record.  Boehm points to evidence of carcasses butchered by archaic humans 400,000 years ago that show cut marks on bones that are "chaotic and varied" suggesting that several people did the butchering, consistent with what is observed in chimpanzee and bonobo meat eating scenes.  More recently, about 200,000 years ago there is evidence of cut marks on the bones of animal carcasses that are consistent with a single individual acting as butcher "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" where the hunters turn the carcass over to a "neutral meat distributor who is uninvolved with the kill," preventing a successful hunter from egoistically controlling the meat.  In contrast, while chimpanzees do share meat, it not a significant part of their diet and the meat does not come from large animals. The strategic motivation for meat sharing among chimpanzees appears to be for the support alliances with other chimps to maintain alpha male dominance within a group rather than support an egalitarian social environment between them. 

We can note several things about Boehm's hypothesis.  The timetable is consistent with the evolution of a larger brain in humans that we know is organized to be more socially responsive to others, both emotionally but also in terms of exercising self-control.  Boehm estimates that human moral origins appeared 35-45,000 years ago.  Interestingly, this suggests that it took about 150,000 - 160,000 years for the larger-brained homo sapiens to evolve their group structures and emotions to support collaborative hunter-gatherer groups. Did the structure of the human brain subtly evolve during this period so that certain homo sapiens with a particular brain structure and types of neurons were selected over other homo sapiens who did not have the same organization? The timetable is also consistent with what we believe occurred with the development of spoken language in humans, which has to be a key to the development of moral rules among humans. Boehm cites evidence of "preaching behavior" among egalitarian hunter-gatherer societies that may have been important to "behaviorally amplify the sympathetic generous tendencies of group members," a behavior that carried over to later hierarchical societies among humans that evolved when settled agrarianism later took root.

Finally, "social selection" is not merely the effect of the suppression of free-riding egoists; rather the intimidation and punishment of deviants acts in combination with "reputational selection."  This is a reference to what we have referred to in the previous posts (see September 17, 2012 post and September 12, 2002 post) as indirect reciprocity.  Simply put, for Boehm, there must be an explanation for why humans extend altruism to non-kin and developed a sense of virtue.  I wonder if we are not over-labeling "selection."  I think Boehm is getting close to saying that there is a gene for altruism, and in fact in his chapter titled "Testing the Selection-by-Reputation Hypothesis" he begins to refer to "altruistic genes" and "genes made for altruism."  I am skeptical of this line of thinking.  Clearly, indirect reciprocity among persons who do not know each other well or know each other at all is based on reputation.  It is a real phenomenon. We often join groups based on reputation. But what nature selects for is emotions and feelings, like attachment and sympathy and empathy, and these emotions in combination with other biological attributes selected by nature end up promoting reciprocal altruism, directly and indirectly.

Finally, what the research described by Christopher Boehm reveals is that the origins of human morality appeared tens of thousands of years before humans created social institutions and hierarchies, including religious and governmental institutions.  Importantly, morality precedes religion and the genetic origins (at least some of the genetic origins) of morality can be linked back to hundreds of thousands if not millions of years ago in other species.  Moral behavior is thus part of nature; it is not owned by religion, nor is it religiously inspired, and it predates the human mind's invention of deities.  Boehm suspects that the origins of religious belief in the brain's capacity for patternicity and agenticity, as described by Michael Shermer (see June 12, 2011 post) probably co-evolved with the origins of morality during the late Pleistocene, but gods, religious institutions, and the co-opting of morality by religious institutions came later, when humans began creating permanent communities as they transformed from hunter-gatherers to agrarian life and domestication of animals.

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