Richard Wrangham, Catching Fire: How Cooking Made Us Human (2009)

Edward O. Wilson's research on eusociality led him to identify the nest as a common attribute among the eusocial species.  Although not proven, Wilson surmises that a gene has been suppressed among the eusocial species that silences the brain's program for dispersal from the nest, leading to the sustained survival of the eusocial community.  (September 12, 2012 post)  Humans are included among the eusocial species, but humans disperse; they do not build and congregate in nests, but they do build and maintain social communities comprised of multiple generations and humans are organized into groups by altruistic division of labor, which are characteristics of eusocial species.  As a surrogate for the nest, Wilson suggests that the campfire served a nest-like function in the development of the genus homo, which strongly suggests that  mastery of fire was critical to humans eusociality. 

As I read Wilson's The Social Conquest of Earth (see September 12, 2012 post), I was reminded of a book on the bookshelf that addressed this topic, Richard Wrangham's (see  July 1, 2010 post)  Catching Fire: How Cooking Made Us Human.  Wrangham believes that mastery of fire was critical to human evolution, but even more important, mastery of fire enabled early humans to cook their food on a regular basis. According to Wrangham, cooked food is even more significant than mastery of fire for human evolution.  Armed with data and concrete examples Wrangham demonstrates that eating cooked food is linked to two evolutionary changes in the human body:  (1) comparatively smaller, more efficient digestive systems (particularly the stomach and the small intestine) that require less energy to digest food and absorb nutrients than our predecessors, and (2) larger brains.  Large brains require significant amounts of energy, and that energy is available to the brain only if it is not needed for other activities essential for survival such as eating and digesting.  Compared to apes and chimpanzees (and presumably extinct australopithecines and habilines), humans spend a fraction of their daily life eating and digesting food.  Apes and chimps spend hours eating plant food or fruit every day.  The relative weight of the human gut is roughly only 60% of the relative weight of the gut of apes and chimpanzees.

The controversial question is when did the first species among the genus homo begin cooking food?  For certain the benefits of and development of a preference for cooked food was accidentally discovered.  Wrangham believes that human cooking begins with homo erectus.  There is anthropological evidence cited by Wrangham that cutting meat with primitive stone tools began as early as 2.6 million years ago.  Roughly 300,000 years later, a new species, referred to by some as homo habilis, which still had many australopithecine characteristics, emerged, and roughly another 500,000 years later the species referred to as homo erectus, emerged according the available fossil record and lived on the African continent for nearly 1.5 million years (until roughly 300,000 years ago).  While it is doubtful that homo erectus had language capacity or skills (see January 31, 2013 post discussing homo neanderthalensis), what we do know is that the cranial capacity of early specimens of homo erectus was 200cc greater than homo habilis and later specimens 400-500cc greater than homo habilis, representing an increase in brain size of approximately 33-75% over the habilines.  (See November 21, 2012 post).  That would be the largest incremental percentage increase from species to species within the genus homo. Homo erectus is recognized to be, in many respects, to be much closer to modern homo sapiens than homo habilis.  Combined with some evidence of the use of controlled fire at sites where homo erectus bones have been found, the control of fire and the significant increase in brain size (the energy for which is enabled by decreased energy used in eating and digesting food) lead Wrangham to identify homo erectus as the first human species to favor and consume cooked food on a regular basis.  Wrangham also speculates that homo erectus, unlike its predecessors, favored sleeping on the ground (instead of trees) and the control of fire would have been useful in providing light to see predators at night or keeping predators away.  The morphology of erectus is not as suitable for sleeping in trees as its predecessors.

Others (Aiello and Wheeler) have concluded that cooking food is the invention of homo heidelbergensis (the predecessor to homo neanderthalensis) a later species.  Aiello and Wheeler believed that brain size was steady among homo erectus until the emergence of heidelbergensis with its larger brain.  Wrangham finds the fossil record sufficient to support the view that brain size gradually grew among erectus and believes that the steady increase in size is attributable to improved cooking techniques, and that continued growth in brain size to heidelbergensis and ultimately to homo sapiens is likely similarly associated with improved cooking techniques, not cooking as a novel adaptation or spandrel. 

Wrangham's thesis is this:  "An important step in fire's becoming a central part of human lives was to maintain it at night.  Suppose some habilines carried a smoldering log by day to protect against predators, then left it at the base of a sleeping tree when they climbed to make a nest at night.  It would not have been such a big step to give it extra fuel so the log will still be burning the next day --perhaps after seeing this happen first by accident.  From there it would have been a smaller step to sitting near the fire to keep it burning, and thereby take advantage of its protection, light, and warmth.  Once they kept fire alive at night, a group of habilines in a particular place occasionally dropped food morsels by accident, at them after they had been heated, and learned that they tasted better.  Repeating their habit, this group would have swiftly evolved into the first Homo erectus.  The newly delicious cooked diet led to their evolving smaller guts, bigger brains, bigger bodies, and reduced body hair; more running; more hunting; longer lives; calmer temperatures; and a new emphasis on bonding between females and males.  The softness of their cooked plant foods selected for smaller teeth, the protection fire provided at night enabled them to sleep on the ground and lose their climbing ability, and females likely began cooking for males, whose time was increasingly free to search for more meat and honey."  So despite the relative dearth of evidence of fire dating back to the time of homo erectus, Wrangham believes that the dramatic shift in brain size and tooth size is significant evidence that Homo erectus started the first outdoor cooking kitchen. 

Division of labor by sex.  E.O. Wilson also includes altruistic division of labor among the attributes of eusociality (September 12, 2012 post).  Wrangham has a discussion that dovetails with Wilson on this point.  First, cooked food liberated males to spend more time hunting for meat in a way that chimps and apes cannot because they spend so much time chewing their food.  Fire enabled men to confine their eating time to the hours around dusk and even after dark.  Hunting enabled the male to contribute food to his family (including an extended family group), but this effort was ultimately dependent upon a reliable, predictable economic exchange between women and men.  Women became foragers and this provided a reliable source of food energy in the event that the men of the group returned with no meat.  Women also became primarily responsible for cooking.

Wrangham argues that while relying on cooked food created opportunities for cooperation, more importantly it exposed female cooks to exploitation because cooking takes time and lone cooks could not easily guard their wares from thieves.  This problem was solved, Wrangham believes, by pair-bonds among males and females:  a "husband" ensured that the woman's gathered foods were not taken by others and from this evolved "a simple marriage system." The male provided the female (and their children) with meat.  Consistent with Boehm's observations (see November 21, 2012 post), Wrangham observes (based on anthropological evaluation of modern hunter-gatherers) that meat is actually shared among a larger group that includes not only the male's "wife" and children, but also an extended family (and possibly a stranger).  The female's distribution of gathered food is largely shared just with her "husband" and their children.  In the gathering of food, there may very well be cooperation among women, but the sharing of the gathered food is limited to the immediate family.  Presumably sharing meat among a larger group evolved because direct reciprocity is essential to the hunting and killing of the large animal, bringing the meat back to the campfire and slaughtering it. 

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	ECS	Consequences	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	Happiness

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 homo, mastery 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 women.  What 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.

Antonio Damasio, Self Comes to Mind (2010)

Antonio Damasio's Self Comes to Mind is the third in a sequence of books in this blog following John Searle's Philosophy in the 21st Century (see January 21, 2011 post) and David Hume's Treatise on Human Nature (see February 27, 2011 post) relating to consciousness and the mind. Searle tees up this sequence by observing that Hume's Enlightenment era view of the mind and consciousness was based on a premise that the "existence of knowledge was in question" and the main task of the philosopher "was to cope with the problem of skepticism." The era of skepticism is now over, Searle says, "because the sheer growth of certain, objective, universal knowledge." So now we fast-forward to the 21st century, where Damasio undertakes a review of that "certain, objective, universal knowledge" we now possess about the neurobiology of the brain, and empirical research that allows us to draw conclusions about how consciousness emerged, and how it is evolving. This is but one example of just how the skepticism of the 18th century Enlightenment has been overcome by the objective, universal knowledge of the 21st century.

First, that "certain, objective, universal knowledge" about the brain and consciousness is not yet complete. Damasio says that, and Searle states that this is not a problem for declaring that the era of skepticism is over --- that our current state of knowledge is capable of being corrected, revised and supplemented without undermining his conclusion (See January 21, 2011 post).

So what is it that we now know about the mind and consciousness that David Hume and his Enlightenment era contemporaries did not know on this subject? Two things: without doubt our knowledge of the brain and the neurosensory system has grown measurably; second, that Hume's introspective conclusions about the mind and consciousness (which were not necessarily his views alone) were very close to what all that cumulative, objective knowledge has revealed over 300 years.

Our current knowledge of the brain, the mind and consciousness must necessarily begin with an evolutionary understanding of the nervous system to which the animal brain is connected. Hume, as I have pointed out in a previous post (see May 24, 2010 post) probably would have appreciated this approach, although he lived a full century before Charles Darwin published On The Origin of Species. Damasio devotes a chapter to the evolution of conscious and non-conscious processes beginning with unicellular organism's sensory and motor capabilities to the multicellular organism consisting of cells with specialized functions --- including neural cells --- that abandoned their "independent status" to cooperate with other types of cells "to be part of a convenient new aggregate." Damasio's discussion is not new --- Steven Rose has a more thorough discussion of the evolution of the nervous system and brains in The Future of the Brain; Nicholas Humphrey's A History of the Mind develops the evolutionary history of the sensory system -- particularly with respect to vision; and Lynch and Granger's Big Brain outline the evolution of primate brains and the auditory sensory system. Damasio's take-away, however, and one that is important to a key thesis, is that the animal nervous system evolved because the organism needed some component to manage and control the organism's survival. As more complex organisms evolved, this required more complex nervous systems and brains to regulate the organism internally as well as externally. Yet even very simple organisms --- organisms without brains --- had the ability to sense changes in their environment: changes in their internal organism environment, as well as their external environment (light, chemicals, even touch) and they could respond to those changes. As Darwin, said, "From so simple a beginning. . ." That early, regulatory "component" is the precursor to the modern human's brain stem. The brain stem is still performing most of the same types of functions in humans that it performed in reptiles millions of years ago --- receiving signals from and monitoring the internal milieu of the body and sending signals back to the body. Certain nuclei in the brain stem are responsible for wakefulness --- a key attribute of consciousness: we know this because when there is damage to specific parts of the brain stem the result is coma and the vegetative state (lack of consciousness).

What we know now, that we did not know in Hume's time, is that the nervous system operates by electro-chemical means. Neuroscience has identified several molecules in the nervous system that are related to states of reward or punishment and are associated with biological value tied to life regulation and survival. There are molecules that suppress and molecules that stimulate, "punish" and "reward," causing the body to generate certain feelings, emotions, and also causing motion to occur. Central to understanding survival mechanisms, says Damasio, is the concept of homeostasis: "In other words, life requires that the body maintain a collection of parameter ranges at all costs for literally dozens of components in its dynamic interior. All the management operations to which I alluded earlier --- procuring energy sources, incorporating and transforming energy products, and so forth --- aim at maintaining the chemical parameters of a body's interior (its internal milieu) with the magic range compatible with life. The magic range is known as homeostatic, and the process of achieving this balanced state is called homeostasis." While we have understood the biological role of homeostasis for most of the 20th century, Damasio asserts that we are only just beginning to understand its significance in terms of neurobiology, psychology, and even sociology (culture).

Damasio is not merely a commentator on this subject. He is a neuroscientist who works with patients suffering pathologies that provide clues about the functionality of certain parts of the brain. He is the author of three previous books that touch on human consciousness: Descartes' Error: Emotion, Reason and the Human Brain, The Feeling of What Happens: Body and Emotion in the Making of Consciousness, and Looking for Spinoza: Joy, Sorrow, and the Feeling Brain. Self Comes to Mind covers much of the same ground that Damasio ploughed in his previous three works, but he builds on those works in several important ways: he supplements his previous writings with a decade of new research (much of which is his own research) following publication of Looking for Spinoza; he revises some of his previous views; and he introduces new hypotheses relative to consciousness that deserve further research in the accumulation of additional "certain, objective, universal knowledge" about the brain and consciousness.

Beyond the brain stem, the evolution of the brain shows that a part of the brain known as thalamus was constructed on top of the brain stem --- it did not replace it --- and operates integrally with the brain stem in producing consciousness. Evolution ultimately added a third component to the brains of some species --- the cerebral cortex. Damasio describes the thalamus as a way station for information that is collected from the body that ferry signals about the body and about the world, from pain and temperature to touch, hearing, and vision (but not smell). All signals bound for the cortex stop at "thalamic relay nuclei and change into tracks that take them to their destinations in varied parts of the cerebral cortex." The thalamus is understood (believed) to facilitate simultaneous and sequenced activation of separate neural sites --- bringing them together in a pattern. It coordinates cortical activities, and in that capacity it is key to the rich conscious experience some species (e.g., humans) have in being able to integrate different sensory experiences as well as memory. The cerebral cortex co-evolved with the thalamus, and acts to keep us awake and selects what we pay attention to. Equally, if not more important for human consciousness, the cerebral cortex is where memory is triggered and the autobiographical self is created.

In an appendix devoted to the architecture of the brain, Damasio fleshes out the different parts of the brain stem and the cerebral cortex and describes that certain, objective knowledge we now have about the functionality of specific parts of the brain. You can't regurgitate it all here, but the point is that our knowledge of how the brain and the mind works --- significantly developed over only the past 20 years --- while not yet complete, is quite substantial. David Hume would be impressed. Some of this knowledge has been enabled by what we learn from pathologies resulting from injury to specific parts of the brain --- informing us that feelings, memories, emotions, wakefulness remain intact or are impaired when a specific brain region is damaged. Some of this knowledge is gleaned from our ability to use functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) to actually observe what is going on in the brain. (See November 13, 2010 post). Consistent with what Miriam Boelyn-Fitzgerald reported in Pictures of the Mind (id.), Damasio writes, "Conscious minds result from the smoothly articulated of several, often many brain sites. The key brain structures in charge of implementing the requisite functional steps include specific sectors of the upper brain stem [particularly the nucleus tractus solitarius, the parabrachial nucleus, the periaqueductal gray, the superior colliculus, and the hypothalamus], a set of nuclei in a region known as the thalamus, and specific but widespread regions of the cerebral cortex."

What the brain is able to do --- connected as it is to the electrochemical network of the central nervous system --- is "map" sensations, both internal to the body itself, and externally received from the environment around us. "Networks of neurons eventually come to mimic the structure of parts of the body, literally mapping the body for which they work and constituting a sort of virtual surrogate for it, a neural double," says Damasio. The components of the upper brain stem mentioned above are capable of providing whole-body maps to the central nervous system. Mapping of the environment around us occurs in the cerebral cortex. The concept of "mapping" (including what Damasio refers to as "somatic marking"), is not new to neuroscience. It is the subject of Damasio's earlier work, The Feeling of What Happens, and in Self Comes to Mind, Damasio reinforces many of his prior hypotheses on this subject with more recent research.

Damasio believes that the regulation of the internal organism occurs in the upper brain stem of a given specie, which creates an "image" of a "protoself." This "protoself" is neither an objective "me" nor a subjective "I," but what he calls "primordial feelings" --- "a direct experience of one's own body, wordless, unadorned, and connected to nothing but sheer existence." These are body events, including pain and pleasure. We cannot yet call this consciousness, but primordial feelings are essential building blocks of consciousness. Damasio describes the neural networks that manage the internal organism "dispositional networks": almost formulaic "predisposed" responses of the body to an environmental condition designed to maintain homeostasis --- i.e., when 'X' occurs inside the body, there is a response 'Z.' And for a long-time, these dispositional networks worked perfectly well, evolving themselves to become even more precise and more customized. As the brain evolved, the thalamus and the cerebral cortex evolved on top of the brain stem. The mapping networks mentioned above, Damasio argues, evolved with these additions to the brain and joined forces with the dispositional networks.

Consciousness emerges with what Damasio calls the "core self," which is about action --- specifically, about a relationship between the organism and an object. The core self emerges because the thalamus and the cerebral cortex map to create images of external objects derived from sensory perceptions, and one of those external objects can be organism itself --- this is the "self as object," a conscious recognition of "me." He refers to this as "core consciousness." Beyond core consciousness, emerging from the more complex cerebral cortex in primates, humans, and perhaps whales and dolphins, is the autobiographical self, and what Damasio calls "extended consciousness." The autobiographical self recognizes "I," and memory is a key part of the architecture of the brain that enables the autobiographical self -- the "self as knower."

Nobelist Eric Kandel's research on memory and the brain explained how memories are chemically developed through the strengthening of synaptic connections, modified through learning. Damasio introduces a new view on the "architecture of memory" that has considerable explanatory power for how memory is retrieved. Ironically, it smacks of David Hume's associationism. By Damasio's account of how the brain retains memories, larger human brains lack the storage capacity for "large files of recorded images of prior events." To solve this problem, human brains "borrowed the dispositional strategy" from early evolution that allows us to be able to retrieve those memories without, figuratively speaking, having to film and store those images. Here is how Damasio says this works. The ancient dispositional networks and the more recent, evolutionarily speaking, mapping networks in the brain are now connected. A current perception triggers the dispositional network that directs the brain to reassemble aspects of past perceptions from the part of the cerebral cortex that had been previously activated when an original perception of an object occurred and where the representation or image was mapped. This occurs in what Damasio refers to as convergence-divergence zones that record "the coincidence of activity in neurons hailing from different brain sites, neurons that had been made active by the mapping of a certain object." A part of the cerebral cortex is devoted to image space where images of all sensory types occurs and map-making occurs; a separate part of the cerebral cortex is devoted to dispositional space where the tools exist to reactivate and generate images previously experienced. The contents of dispositions, Damasio says, are always unconscious --- he says they are "encrypted" and "implicit" --- in contrast to the explicit images in the image space created by current perceptions. The "encrypted" dispositions are not themselves images, but merely implicit formulas for how to reconstruct maps in image space. Our "knowledge base" is, by this hypothesis, part of our unconscious brain, stored in code, waiting to be retrieved from what Damasio refers to as "association cortices" (and hence the analogy to Hume's associationism). The tools for language are maintained here as well.

Damasio's account of short-term and long-term memory is not Damasio's own conclusions, but his model of convergence divergence zones is. Kandel, in his autobiography In Search of Memory, describes the work of Brenda Milner and others that showed that short-term (conscious, explicit) and long-term (unconscious, implicit) memory required different anatomical systems. In the words of Kandel: "Implicit memory is not a single memory system but a collection of processes involving several different brain systems that lie deep within the cerebral cortex. For example, the association of feelings (such as fear or happiness) with events involves a structure called the amygdala. The formation of new motor (and perhaps cognitive) habits requires the striatum, while learning new motor skills or coordinated activities depends on the cerebellum. . . Implicit memory often has an automatic quality. It is recalled directly through performance, without any conscious effort or even awareness that we are drawing on memory. Although experiences change perceptual and motor abilities, those experiences are virtually inaccessible to conscious recollection." Damasio suggests that "neurons in anterior medial temporal cortices can indeed respond to unique objects [e.g., one's grandmother], in perception or recall, with high specificity suggesting that they receive convergent signals [where one neuron is influenced by many others, resulting in a convergence of input]. But the mere activation of those neurons, without retroactivation that would follow it, would not allow us to remember our grandmother or remember her. To recognize or remember our grandmother, we must reinstate a substantial part of the collection of explicit maps that, in their entirety, represent her meaning." Damasio believes that this neural experience associated with the recall of past events is not unlike the mechanism by which mirror neurons (see Sept. 18, 2009 post) are involved with feeling the movement of others.

From memory, humans and a few other species, are able to recall their own biographical experiences and this gives rise to the autobiographical self -- not the object "me," but the subjective "I" --- "memory made conscious." This is what Damasio calls extended consciousness.

One cannot leave Damasio without acknowledging his views on feelings and emotions. This is not new to Self Comes to Mind, but is at the core of his earlier books and articles. The subject of feelings and emotions is integral the discussion of the protoself and the core self. "Emotions are complex, largely automated programs of actions concocted by evolution. The actions are complemented by a cognitive program that includes certain ideas and modes of cognition, but the world of emotions is largely one of actions carried out in our bodies, from facial expressions and postures to change in viscera and internal milieu. Feelings of emotion, on the other hand, are composite perceptions of what happens in our body and mind when we are emoting. As far as the body body is concerned, feelings are images of actions rather than actions themselves; the world of feelings is one of perceptions executed in brain maps. But there is a qualification to be made here: the perceptions we call feelings of emotion contain a special ingredient that corresponds to the primordial feelings discussed earlier. Those feelings are based on the unique relations between body and brain that privileges interoception." The experience of feelings and emotions, while generated largely by brain-stem neural systems, are critical to the core self: we feel our perceptions, and "once a protagonist (me, I) is added to the process, the experience is claimed by its newly minted owner, the self." For Damasio, like Hume, our conscious, "rational" decision-making is tied feelings and emotions and the unconscious, automated aspect of our brain and body.

Recall the structure of Hume's Treatise on Human Nature: Part I (On the Understanding) articulates that our knowledge begins with an immediate perception of our memory or senses, or by an inference from some other cause, which we must ascertain either by a present impression or by another inference. When we rely on inferences, our knowledge of something is believed to be more likely because of repetitive experience that strengthens our memory of the object or experience. So far, Hume is in sync with the 21st century, although we are less skeptical today of treating sensory impressions as something distinct from reality --- today we have considerably more objective knowledge about causal relations. On the question of "personal identity" (the self), Hume states that "the identity to which we ascribe to the mind of man is only a fictitious one": Hume suggests we cannot know ourselves, but only our perceptions. On this point, Damasio would say that Hume "pulverized the self to the extent of doing away with it." In Damasio's nomenclature, Hume is only willing to recognize a protoself and cannot find his way to acknowledge the core self or even the autobiographical self. This is surprising, because in Part II (Of the Passions) Hume exhibits considerable understanding and command of human emotions. In discussing pride and humility, Hume states that although they are contrary to one another, "they have the same object: This object is self, or that successions of related ideas and impressions, of which we have intimate memory and consciousness."

Hume's treatment of emotions is not radically different than Damasio's, because Hume's catalog of emotions largely fall under the label of what Damasio refers to as the "social emotions," which Damasio believes are of recent evolutionary vintage, some of which may be exclusively human. For both Hume and Damasio, emotions shape our reasoning: "rational" choice, if you will, is not independent of or from emotions and feelings. Compassion (empathy/sympathy) is one of those social emotions, and compassion, along with admiration, is critical in building a social construct in Damasio's view. And so it is with Hume, as Part III (On The Morals) states that sympathy with public interest is the source of moral approbation, and ultimately reciprocal promise-making behavior and principles of justice: "sympathy is a very powerful principle in human nature, that it has great influence on our taste of beauty, and that it produces our sentiment of morals in all the artificial virtues."

Just as Damasio acknowledges the role of mirror neurons in allowing us to understand the action of others, Hume seems to anticipate the same as well as Dacher Keltner's observations about emotions in Born to be Good (see July 16, 2010 post). Hume writes, "As in strings equally wound up, the motion of one communicates itself to the rest; so all the affections readily pass from one person to another, and beget the corresponding movements in every human creature. When I see the effects of passion in the voice and gesture of any person, my mind immediately passes from these effects to their causes, and forms such a lively idea of the passion, as is presently converted into the passion itself. In like manner, when I perceive the causes of any emotion, my mind is conveyed to the effects, and is actuated with like emotion."

By the end of Self Comes to Mind, Damasio extends his to discussion of consciousness to the origins and development of culture. He returns to the concept of homeostasis (detecting imbalance in life process and correcting it within the constraints of human biology and of the physical and social environment): with an autobiographical self capable of reflection, and new forms of memory enhanced by forms of communication including gestures and language, and the invention of external memory systems (e.g., drawings on caves, tablets, books, film, computers), humans begin to invent ways to govern social behavior, including morality, justice systems, economics, science and technology. Hume ends up here as well, but with Damasio we have those objective facts and hypotheses in need of further research that Hume did not have at his fingertips. And we have the research of others such as Michael Gazzaniga (see September 27, 2009 post), Marco Iacoboni (see September 18, 2009 post), Dacher Keltner (see July 16, 2010 post), and Marc Hauser's Moral Minds that adds to the accumulated, objective knowledge, which John Searle recognized represents a critical difference between epistemology today and Enlightenment-era skepticism.

Michael Gazzaniga, Human (2008)

In the September 18th post, I concluded that a grander treatment of the subject of mirror neurons should be forthcoming someday, a volume that more completely integrates the role of mirror neurons with the biological operations of the mind and body and discusses consciousness memory, and evolution. I did not expect that such a book was already on The Bookshelf and was the next book to come off the shelf. Human, by U.C. Santa Barbara neuroscientist and psychology professor, Michael Gazzaniga , is such a book. While not specifically about mirror neurons, this larger look at the landscape of language, memory, emotion, perception, primate evolution and behavior, infant behavior and development of the human brain gives due recognition to discovery and role of mirror neurons.

In the Mystery of Consciousness, University of California philosophy professor, John Searle, writes, "The mystery of consciousness will gradually be removed when we solve the biological problem of consciousness." That's a remarkable statement from the philosophical community, where for millenia its leading lights have been debating and struggling with non-biological metaphysical ideas about what form reality takes and how we know reality. For Searle, who rejects the mind-body dualism of Descartes, "The 'problem of consciousness' is the problem of explaining exactly how the neurobiological processes in the brain cause our subjective states of awareness or sentience. . . the problem of consciousness is a scientific research project like any other." And that is a task that Gazzaniga embarks upon in Human.

While Searle appears ready to jettison philosophy of the mind for the biology of the mind, it is my belief that understanding the human mind is primarily biology and chemistry and physics (neuronal activity after all is electro-chemical), but it is also empirical anthropology, paleontology, research about other species, sociology, and psychology too. The human brain is the most important feature that distinguishes humans from other species. Gazzaniga would agree, and Human is engaging on all disciplines. There is a growing body of research that recognizes this interdisciplinary approach including Pascal Boyer's Religion Explained , Paul Bloom's Descartes' Baby , Steven Rose's The Future of the Brain , and Marc Hauser's Moral Minds. Each of these books explores one or more of the aspects of Gazzaniga's inquiry: what is unique about being human? which explores the answer inside the human mind.

Philosopher Searle and neuroscientist Antonio Damassio reject Cartesian dualism, but neuroscientist Gazzaniga says: we all act like dualists. "We are animate objects, which are the subject to the physical laws of animate objects, but we also have nonperceptual psychological properties not subject to physical laws." It is the latter that is one of the unique of attributes of being human: "we are the only animals that reason about unobservable forces ... we alone ... try to explain an effect as having been caused by something." That we may "act like" there is an unseen world separate from the physical world does not axiomatically lead to the conclusion that there is a dual world of the mental forms separate from a physical world of the senses. Pascal Boyer has provided one cogent explanation why the human mind is uniquely willing to recognize unseen agents, but he does not conclude that our psychological properties are not subject to physical laws. In the end, Gazzaniga does not appear to disagree. Gazzaniga is well-known for his split-brain research of patients suffering from severe epilepsy and the only treatment is to sever the corpus collosum that connects the right side of the brain from the left side. The right side of the brain is not a problem solver; it is good at perceiving, attentional skills, and emotions, but it is the cognitive left side of the brain that takes all the input coming into the brain and makes sense of it. The left side of the brain, says Gazzaniga, is the "interpreter" of our conscious experience, and in the course of acting as an "interpreter" this biological organ organizes information in a way to create a self-conscious self (an image of ourselves in our mind, separate from our physical self, or as Antonio Damassio calls it, our "movie within a movie"), another unique attribute of what makes us human. But this is the outcome of biological processes, not a feature of a separate world of the mind.

Enough of dualism or not! There are important nuggets of information in Human. The human brain is unique, not merely because of its size relative to our body weight or size, but because the way it is organized into modules and its connectivity. We learn of two genes that are regulators of brain size: microencephalin and ASPM. There is evidence of accelerated evolution of microencephalin in primates, and a variant of microencephalin appeared about 37,000 years ago about the same time that corresponds with culturally modern humans. A variant of ASPM appeared in humans about 5800 years ago, which coincides with the establishment of cities, agriculture, and written language. We don't know whether these genetic developments are in fact linked with cultural development and language, but it is certainly suggestive.

At the end of the book, we meet Merlin Donald who developed what is called mimesis theory: that the ability to imitate motor action is the foundation of language, human consciousness, and human culture. Language and gesture, the subject of the August 31 post on Christine Kennealy's The First Word, requires fine motor skills, which must be flexible enough to involve a voluntary control of muscles to mimic or rehearse an action undertaken by some other animate object, observe its consequences, store it in memory, and then change what must be changed. Donald calls this a "rehearsal loop," which he says is uniquely human. This requires feedback loops in the brain --- part of the brain's connectivity --- whereby the brain's ability to perceive (the right side) is connected the brain's cognitive capacity (in the left side) to connect to the action, and in order for the brain to imitate another animate object (such as another human), the brain must be self-aware. Is it this connectivity that is tied to the genetic developments in humans thousands of years ago?

Finally, we meet Jeff Hawkins, a creator of the Palm Pilot, who has co-authored a book called On Intelligence. Hawkins rejects the idea that the human brain is "computational." The brain does not compute the answers to problems; the neocortex is a memory system, which differs from a computer. The brain uses stored memory from past experience to make predictions -- which Hawkins asserts is the primary function of the neocortex and the foundation of human intelligence. Recall from the September 18 post on Marco Iacoboni's Mirroring People, that the part of the brain where mirror neurons are found is a part of the neocortex, which is responsible for planning and execution. The neocortex is the center or our attentive capacity, and we come to attention when we fail to accurately predict something. So it is here that motor coordination, drawing on memory, planning and execution all occur, with help from other, evolutionarily older parts of the brain tied to the senses. This is a key part of the brain responsible for attention and self-awareness, forming what Damassio characterizes as our "extended consciousness." Hawkins' model of the brain depends on feedback loops where information must flow back and forth comparing what is happening to what is predicted to happen. Information about what is happening flows in one direction; information about what memory tells you is expected to happen flows in another direction. This is not how a computer operates, which relies heavily on parallel processes, and arguably it suggests that robots will never replace us.

I said in a previous post that one of the big three areas for human inquiry is the human mind. Human delineates why this is true. Mirror neurons, fine motor skills that enable us to imitate, connectivity among modules in the brain and feedback loops, extended consciousness, language, and self-awareness are some of the important attributes of what make humans unique. To comprehend how the human mind works is really the key to understanding what makes us unique in the animal kingdom. Not all of the answers are here, but there is a lot in one book to fathom this huge question.