“Cognitive Gadgets: The Cultural Evolution of Thinking” by Cecilia Heyes

In this short, dense book Heyes introduces cultural evolutionary psychology, which seeks to combine cognitive psychology with cultural evolution. She posits that human cognitive traits, which were previously assumed to be genetic, might, instead, be passed on through cultural evolution. Heyes subscribes to the selectionist approach of Donald Campbell, where what is required for evolution to occur is “(1) mechanisms for introducing variation; (2) consistent selection processes; and (3) mechanisms for preserving and/or propagating the selected variations.” Of course, these mechanisms can operate culturally as well as genetically.

Heyes suggests that humans have genetically inherited three basic traits that have helped with domain-general learning. First, by temperament humans are extremely social primates, which has facilitated coordination amongst large groups and learning through others. Second, humans have “genetically inherited attentional biases [that] ensure that the attention of human infants is locked-on to other agents from birth.” This includes a propensity to look at the faces of others and gaze-cuing, where attention is focused on the object of another’s attentional gaze. Therefore, “the flow of information that infants receive about the world is guided by adults’ knowledge of what is important and interesting.” Familiar voices, such as the mother’s, as well as native language speech in general, also attract inordinate attention in infants. Finally, humans have inherited powerful information processors, which are domain-general. The human pre-frontal cortex is proportionally larger than in the brain of any other primate. Associative learning techniques and cascading effects allow humans to process ever-more information, while human’s large memory allows for exceptional retention. In addition, executive function, consisting of inhibitory control, working memory, and cognitive flexibility, allows humans to develop such facilities as reasoning, problem solving, and planning. “Cognitive mechanisms that we have reason to believe are distinctively human…. include: (1) mechanisms that are specialized for dealing with the inanimate world, such as causal understanding; (2) faculties that are equally likely to process animate (social) and inanimate (asocial) events, such as episodic memory; and (3) various forms of cognition specialized for dealing with social stimuli, such as face processing, imitation, and mindreading.”

Heyes makes the case that “most social learning- perhaps all non-cultural social learning- depends on the same learning mechanisms as asocial learning, and that these are broadly associative processes that encode information for long-term storage by forging excitatory and inhibitory links between event representations.” What makes humans unique, however, is selective social learning. This is explicit metacognition techniques that “focus social learning on knowledgeable agents so precisely that they encourage high-fidelity copying of behavior. Because it is exclusive, specific, and accurate, this kind of copying promotes cultural evolution by enhancing “parent-offspring relations”…. Explicitly metacognitive rules are typically learned through social interaction and, therefore, show marked cross-cultural variation.” Most importantly, “metacognitive social learning strategies are learned from others (emphasis mine).” In contrast, “the behavior of nonhuman animals and young children can be described and predicted by formulae such as copy the successful or copy older individuals, but the strategies or rules are in the minds of scientific observers, not the actors themselves.” By adulthood, humans are unique in explicitly choosing successful prototypes to mimic. This selective social learning is then passed down and retained only as it is useful. The ability to selectively copy is culturally learned.

According to Heyes, a second cognitive gadget, passed down through cultural evolution, is imitation. This formation solves Andrew Meltzoff’s correspondence problem, where he asks how can cognition “connect the felt but unseen movements of the self with the seen but unfelt movements of the other?” Heyes suggests, “the link between the sensory and motor representations is bidirectional and excitatory…. Matching vertical associations are forged by learning, predominantly social learning, they are not inborn or genetically inherited.” Vertical associations are formed through “correlated sensorimotor experience: experience in which seeing and doing a particular action occur close together in time and in a predictive or “contingent” relationship.” Opaque perception is facilitated by cultural tools such as mirrors, video recordings, synchronized activities and rituals, such as dance, drills and games, action words that provide equivalence experience, and feedback through adults imitating infant behavior in a mirrored way. Heyes suggests that “the most important function of imitation [is] high fidelity cultural inheritance not of object-directed actions, but of communicative and gestural skills…. They include the sequences of body movements that enable group members to communicate without words and, thereby, to coordinate their activities when words are absent (for example, when the message is ineffable, and before language co-evolved), and when words are dangerous (for example, when a group is stalking prey). They also include the sequences of body movements, such as those involved in ritualistic dancing, that enable group members to bond- to achieve the states of trust and commitment required for cooperative action.” Finally, “identical twins are no more alike in their imitative ability than fraternal twins” suggesting that skill in imitation is not genetically inherited.

The third cognitive gadget Heyes brings up is theory of mind. She suggests that theory of mind was a necessary prerequisite for teaching, “acts with the intention of producing enduring change in the mental states- especially the knowledge states- of another agent.” Heyes suggests that theory of mind is not a concept that is inherited genetically, but that “children are taught about the mind by members of their social group, and the information that is culturally inherited in this way forms a conceptual structure enabling the ascription of mental states to the self and others.” Heyes continues, “mindreading involves the derivation of meaning from signs…. The signs are facial expressions, body movements, and utterances- many of them conventional- and their meaning relates to the actor’s mental states…. Novice mindreaders learn not only that behavior can be, but that it should be, produced by rational interactions among beliefs and desires, and they are encouraged to make their own behavior obey these conventions.” Many of these social beliefs are culturally specific and, therefore, cannot be inherited genetically.

The fourth cognitive gadget Heyes touches on is language. She admits that she is not an expert in this field, but she still ambivalently concludes that language acquisition is more culturally than genetically inherited. “The cognitive processes of language acquisition evolved genetically to fulfill nonlinguistic functions.” Domain-general tools that evolved genetically became culturally evolved to facilitate language, uniquely in humans. Heyes came to this conclusion through empirical studies which questioned a genetic Universal Grammar, first posited by Chomsky. Studies of the five to eight thousand languages spoken in the world today show that there is little universal linguistically be it phrase category, phrase structure, linear order, numerals, or even the basic concepts of nouns, verbs, adjectives, and adverbs. Some languages lack adverbs entirely, whereas others adopt a fifth major category, ideophones. Furthermore, fMRI studies have shown that neural activity is spread out across the brain during language processing, not focused in Broca’s area as Universal Grammar proponents had previously insisted. Computer simulations have also shown that complex grammatical construction can be acquired using domain-general tools. Other studies have taught adult humans “artificial grammar”, which uses arbitrary rules, effectively. Other studies have concluded that “Universal Grammar could not have evolved genetically because linguistic conventions change too quickly.” Rules of parsimony also suggest that domain-general processing should be sufficient to generate language acquisition in humans, through cultural evolutionary mechanisms alone.

Heyes concludes by defending the idea of group selection. She suggests that these cognitive gadgets, distinctly human cognitive mechanisms, all evolved through cultural evolution at the group level. These mechanisms increased fitness for individuals by improving their living conditions and increasing their likelihood of reproducing, but they also helped at the group level because “groups with better living conditions are more likely to persist through time and to bud, not only because their members are more likely to survive and reproduce, but also because these groups are more likely to attract net immigration. Groups with better living conditions are also more likely to have their practices emulated by other groups, including childrearing and ritual practices that foster the development of particular cognitive mechanisms.” These mechanisms are amplified through network effects that “go on between people, rather than inside individual’s heads- such as conversation, storytelling, turn-taking, collective reminiscing, teaching, demonstrating, and engaging in synchronous drills.” Inheritance of these cultural mechanisms can take place through many routes (vertical, oblique, or horizontal copying) and, therefore, the mechanisms become more robust over time. Also, redundancy of routes can amplify and solidify acquisition. Children “have many opportunities to pick up and consolidate the same information…. And this does not occur by chance, or as a consequence of a blind selection process.” Many of these specific mechanisms are locally, but not globally, optimal in their particulars. “Distinctively human cognitive mechanisms need to be nimble, capable of changing faster than genetic evolution allows.” With the growth of human group size, specialization allowed for expertise and, as new techniques emerged, they were more likely to be seen by others, imitated, and passed on to the next generation. “Cultural evolutionary psychology, the cognitive gadgets theory, suggests that distinctively human cognitive mechanisms are light on their feet, constantly changing to meet the demands of new social and physical environments.”

“Who We Are and How We Got Here” by David Reich

Reich is a professor in the Department of Genetics at Harvard Medical School. This is a book intended to educate the layman on the recent technological advances in genetics. Specifically, it details how the mapping of the complete human genome, along with subsequent tests on samples from prehistoric and modern humans in the last decade, is changing the received wisdom about patterns of migration and inter-breeding of different populations from 70,000 to 1,000 years ago, previously based on techniques from archeology, linguistics, skeleton morphology, and anthropology.

The first five examples of complete ancient human genomes were only published in 2010- a few archaic Neanderthal genomes, an archaic Denisova genome, and a four-thousand-year-old individual from Greenland. Since then, hundreds more samples of genome-wide data have been analyzed, studied, and published. This was a vast improvement on previous techniques that only analyzed small stretches of the genome, such as mitochondrial DNA. “The genome is written out in twin chains of about three billion chemical building blocks…. What we call a gene consists of tiny fragments of these chains, typically around one thousand letters long.” By analyzing the complete genome, scientists have been able to divine much more detailed information about humanity’s collective past, historical migration patterns, and when human lineages broke off from one another and perhaps came back to co-mingle. “The most recent African ancestor of all the branches [of modern humans], “Mitochondrial Eve,” lived sometime after 200,000 years ago. The best current estimate is around 160,000 years ago.”

In this book, Reich first analyzes the relationship between modern humans and Neanderthals. “When we tested diverse present-day human populations, we found Neanderthals to be about equally close to Europeans, East Asians, and New Guineans, but closer to all non-Africans than to all sub-Saharan Africans…. We found that non-African genomes today are around 1.5 to 2.1 percent Neanderthal in origin.” This Neanderthal DNA probably mixed with modern human DNA somewhere between eighty-six thousand to thirty-seven thousand years ago, so we can be certain at least some Homo Sapiens and some Neanderthals were having children together at that point in history. But that was not all. Homo Sapiens were also inter-breeding with Denisovans. “We eventually estimated the separation between the Neanderthal and Denisovan ancestral populations to have occurred 470,000 to 380,000 years ago, and the separation between the common ancestral populations of both of these archaic groups and modern humans to have occurred 770,000 to 550,000 years ago.” From that point on, however, there was still inter-breeding between all these human sub-groups. “Interbreeding between Denisovan and New Guinean ancestors occurred fifty-nine to forty-five thousand years ago…. We estimated that about 3 to 6 percent of New Guinean ancestry derives from Denisovans…. The Denisovan-related ancestry in East Asians is about a twenty-fifth of that seen in New Guineans- it comprises about 0.2 percent of East Asians’ genomes, rising to up to 0.3-0.6 percent in parts of South Asia.”

Reich goes on to detail the recent discovery of a ghost population, no longer are alive in pure form today, but who have passed on parts of their genome to present-day humans. These are the Ancient North Eurasians. “There was a population living in northern Eurasia that was not the primary ancestral population of the present-day inhabitants of the region. Some people from this population migrated east across Siberia and contributed to the population that crossed the Bering land bridge and gave rise to Native Americans. Others migrated west and contributed to Europeans…. All told, more than half of the world’s population derives between 5 percent and 40 percent of their genomes from the Ancient North Eurasians.” Reich describes the process of migration (and the breeding that went along with it) as more akin to a trellis, than the more common tree branching metaphor. These populations separated and then often recombined as they moved about, traded with or invaded others, and relocated around the globe. In fact, the Mal’ta genome (a boy found in south-central Siberia, who lived about twenty-four thousand years ago) has strong genetic affinity to modern Europeans and Native Americans, but has little resemblance to modern-day Siberians. “The analysis of the Mal’ta genome made it clear that Native Americans derive about a third of their ancestry from the Ancient North Eurasians, and the remainder from East Asians. It is this major mixture that explains why Europeans are genetically closer to Native Americans than they are to East Asians.” 

In Europe, further ghost populations were found in West Eurasia. “About ten thousand years ago there were at least four major populations in West Eurasia- the farmers of the Fertile Crescent, the farmers of Iran, the hunter-gatherers of central and western Europe, and the hunter-gatherers of eastern Europe. All these populations differed from one another as mush as Europeans differ from East Asians today.” The Bronze Age was the time when these distinct populations mixed and homogenized, perhaps as the result of technological and cultural integration as well. Furthermore, “five thousand years ago, the people who are now the primary ancestors of all extant northern Europeans had not yet arrived.” The Yamnaya were sheep and cattle herders who originally came from the Steppe. They promulgated, if not invented, the wheel and domesticated the horse. “In Germany, people buried with Corded Ware pots derive about three-quarters of their ancestry from groups related to the Yamnaya and the rest from people related to the farmers who had been the previous inhabitants of that region.” It is also likely that the Yamnaya were the ones who spread the origins of all Indo-European languages as they spread their genes, technology, and culture across Europe.

In India, Reich found the people today “are the outcome of mixtures between two highly differentiated populations, “Ancestral North Indians” (ANI) and “Ancestral South Indians” (ASI), who before their mixture were as different from each other as Europeans and East Asians today. The ANI are related to Europeans, central Asians, Near Easterners, and people of the Caucasus, but we made no claim about the location of their homeland or any migrations. The ASI descend from a population not related to any present-day populations outside India. We showed that the ANI and ASI had mixed dramatically in India. The result is that everyone in mainland India today is a mix, albeit in different proportions, of ancestry related to West Eurasians, and ancestry more closely related to diverse East Asian and South Asian populations. No group in India can claim genetic purity…. We found that West Eurasian-related mixture in India ranges from as low as 20 percent to as high as 80 percent.” This cut across all regions and castes, although the higher castes and males both tended to have a higher proportion of ANI ancestry. The Andamanese were the lone population with zero European genes at all, likely because of their secluded island location. However, within sub-castes in India, Reich did find long strings of identical genetic code, suggesting that “long-term endogamy as embodied in India today in the institution of caste has been overwhelmingly important for millennia.”

Reich’s analysis also provided revelations for the migration patterns of humans into the Americas. “There were at least two migrations that left a human legacy as far as South America and at least two whose impact was limited to northern North America.” These paths split more like tree branches than trellises, with little remixing after the initial separations. “The splits proceeded roughly in a north-to-south direction, consistent with the idea that as populations traveled south, groups peeled off and settled, remaining in approximately the same place ever since.” In the Americas, population displacement was not common. However, one unusual pattern was that “a sublineage of First Americans that originated well after the initial diversification of First American lineages in North America migrated back to Asia.” Migrations patterns are often not obvious, but the genetic codes do not lie.

Reich next moves on to East Asia, which “has been home to the human family for at least around 1.7 million years, the date of the oldest known Homo erectus skeleton found in China…. In Australia, archaeological evidence of human campsites make it clear that modern humans arrived there at least by about forty-seven thousand years ago, which is about as old as the earliest evidence for modern humans in Europe…. Chinese and Australians derive almost all their ancestry from a homogenous population whose ancestors separated earlier from the ancestors of Europeans.” As in West Eurasia, East Asian modern humans soon out-competed archaic humans and completely replaced them in every region that they migrated to. Today’s East Asians derive their ancestry from one of two ghost populations, one starting out around the Yangtze River Basin and the other from around the Yellow River. The Yellow River Ghost Population largely spread west, ending at the Tibetan plateau, while the Yangtze Ghost Population spread to southeast Asia and Taiwan. Often new genetic information in combination with traditional archaeology can yield revelations. For instance, in Japan “around twenty-three hundred years ago, mainland-derived agriculture began to be practiced and was associated with an archeological culture with clear similarities to contemporary cultures on the Korean peninsula…. Present day Japanese have about 80 percent farmer and 20 percent hunter-gatherer ancestry.” That genetic mix yields an approximate date of inter-breeding of sixteen hundred years ago. That means for hundreds of years, the two populations both lived on the islands of Japan, but with relatively little inter-breeding, until social segregation broke down, interbreeding began, and homogenization occurred.

As for Africa, “African genome sequences are typically about a third more diverse than non-African ones.” Most migration patterns moved in a north-to-south direction. “There is little if any sub-Saharan African related ancestry in ancient Near Easterners or Egyptians prior to medieval times.” Surprisingly, Ethiopian “caste” groupings have proven to have gone back generations further than even those in India. The modern Ari are the oldest example of strong endogamy that Reich has thus far come across, persisting at least forty-five hundred years. Another ghost population were the East African Foragers. “We also found that the East African Foragers were more closely related to non-Africans today than they were to any other groups in sub-Saharan Africa. The close relationship to non-Africans suggests that the ancestors of the East African Foragers may have been the population in which the Middle to Late Stone Age transition occurred, propelling expansions outside of Africa and possibly within Africa too after around fifty thousand years ago.”

Finally, Reich concludes his book with controversies associated with these genetic breakthroughs. Race may be a social construct, but it is still a touchy cultural subject. Racial variations are existent, if not determining. “Around 85 percent of variation in the protein types could be accounted for by variation within populations and “races,” and only 15 percent by variation across them.” Inter-breeding was also not propagated randomly. Cultural factors such as inequality played a role in whose genes were passed on. “The contribution of European American men to the genetic makeup of the present-day African American population is about four times that of European American women.” These numbers are even more skewed for the populations of South and Central America for obvious historical reasons. Somewhat less controversially, “8 percent of males in the lands that the Mongol Empire once occupied share a characteristic Y-chromosome sequence or one differing from it by just a few mutations.” The dating of such a “star-cluster” founder, estimated through the rate of the accumulation of mutations on the Y-chromosome, can be placed to between thirteen hundred and seven hundred years ago and then history can guess that Genghis Khan would be the best possible human match to fit such a profile. Finally, as of today the DNA revolution has been dominated by the testing of Europeans, both modern and archaic. “Of 551 published samples with genome-wide ancient DNA data as of late 2017, almost 90 percent are from West Eurasia.” That is because most state of the art techniques and labs were first developed in Europe, but also because DNA from warmer climates is more likely to degrade and harder to extract and many countries, such as India and China, limit the exportation of DNA material outside their borders. Scientists are still in the early days of this genetics revolution. Reich compares this technological breakthrough to the inventions of the microscope and of carbon dating in scientific significance. Genome-wide mapping is a burgeoning field and the future growth in new techniques is only going to expand the scope and scale of the DNA samples available for analysis.

“Stream System- The Collected Short Fiction” by Gerald Murnane

This is a collection of short stories written by Murnane over the past fifty years. Some stories are as short as five pages while the longest span around a hundred. What connects them all is Murnane’s use of imbedded stories within stories. “Somewhere today in a suburb of Melbourne is a man who calls himself a writer of fiction but who writes, in fact, a sort of diary of the man he wishes he could be.” He constantly mines the territory of his home state of Victoria, Australia. “I admired him, for one thing, because he preferred to look at his land rather than farm it.” He also returns to themes of writing, reading, and a relationship with books in general. “The writing of fiction was something that a certain sort of person had to do in order to explain himself or herself to an imagined parent or an imagined loved one or an imagined god.” Many of his stories involve the narrator describing the act of writing the very story Murnane is himself writing. Yet the narrator is not identical to Murnane. Or not quite. “I wrote fiction in order to learn the meaning of certain images in my mind.” Murnane again and again goes back to the craft of writing and the mind as the grounds for imagination. “I have always been interested in what is usually called the world but only insofar as it provides me with evidence for the existence of another world.” He is constantly plumbing the depths of the mind for both images and feelings. “A diagram of my mind would resemble a vast and intricate map with images for its small towns and with feelings for the roads through the grassy countryside between the towns.” Like in his novels, it is hard to decipher what comes from the facts of his real life and what details are made up whole cloth. “Even to his wife and children he had sometimes said that Sunday afternoon was the saddest time of the week: the time when you had to admit that you were no more than the person you were. To himself he would have added that Sunday afternoon was the time when he tried to understand how he had come to be who he was and where he was rather than someone else in some other place.” His nested stories and asides often seem more important and real than the original thread of his story. “I have trusted for many years that I will remember from every text that I read the few words or phrases that I need to remember.” His digressions into the recesses of his mind are so vivid and illuminating that one forgets where one is while reading his words. “Or I might finish this piece of fiction by mentioning that I have always been drawn to writers who have felt their minds threatened.”

“The Master and His Emissary- The Divided Brain and the Making of the Western World” by Iain McGilchrist

McGilchrist is a former psychiatrist, neuroimaging researcher, and professor of English at Oxford. He believes that the left and the right sides of the human brain, while exhibiting signs of plasticity, do have unique capabilities. The thesis of his book is that “for us as human beings there are two fundamentally opposed realities, two different modes of experience; that each is of ultimate importance in bringing about the recognizably human world; and that their difference is rooted in the bihemispheric structure of the brain. It follows that the hemispheres need to co-operate, but I believe they are in fact involved in a sort of power struggle, and that this explains many aspects of contemporary Western culture.” This thesis is at once simple and revolutionary. McGilchrist begins by pointing out some hard biology. “The corpus callosum contains an estimated 300-800 million fibres connecting topologically similar areas in each hemisphere. Yet only 2 per cent of cortical neurons are connected by this tract.” That is, most of our brain’s neurons are not connected by the only pathway that links our right and left hemispheres. Furthermore, when comparing various animals, the bigger the brain size, the less interconnected the hemispheres are.

McGilchrist points out that “lateralisation brings evolutionary advantages, particularly in carrying out dual-attention tasks…. The right hemisphere appears to be deeply involved in social functioning…. Where there is divided attention, and both hemispheres appear to be involved, it seems probable that the right hemisphere plays the primary role…. More specifically there is evidence of left-hemisphere dominance for local, narrowly focussed attention and right-hemisphere dominance for broad, global, and flexible attention…. What is new must first be present in the right hemisphere, before it can come into focus for the left…. Only the right hemisphere can direct attention to what comes to us from the edges of awareness…. The right hemisphere understands from indirect contextual clues, not only from explicit statement…. The right hemisphere takes whatever is said within its entire context. It is specialised in pragmatics, the art of contextual understanding of meaning, and in using metaphor. It is the right hemisphere which processes the non-literal aspects of language…. The left hemisphere is the hemisphere of abstraction, which, as the world itself tells us, is the process of wresting things from their context. This, and its related capacity to categorise things once they have been abstracted, are the foundations of its intellectual power…. The left hemisphere operates an abstract visual-form system, storing information that remains relatively invariant across specific instances, producing abstracted types or classes of things; whereas the right hemisphere is aware of and remembers what it is that distinguishes specific instances of a type, one from another…. The right temporal lobe deals preferentially with memory of a personal or emotionally charged nature, what is called episodic memory, where the left temporal lobe is more concerned with memory for facts that are ‘in the public domain’…. Not only does the right hemisphere have an affinity with whatever is living, but the left hemisphere has an equal affinity for what is mechanical. The left hemisphere’s principal concern is utility. It is interested in what it has made, and in the world as a resource to be used. It is therefore natural that it has a particular affinity for words and concepts for tools, man-made things, mechanisms and whatever is not alive…. Self-awareness, empathy, identification with others, and more generally inter-subjective processes, are largely dependent upon…. right hemisphere resources…. The right hemisphere plays an important role in what is known as ‘theory of mind’, a capacity to put oneself in another’s position and see what is going on in that person’s mind…. It is a capacity that children do not acquire fully until the age of four…. The right hemisphere is the locus of interpretation, not only of facial expression, but of prosody (vocal intonation) and gesture…. The left hemisphere reads emotions by interpreting the lower part of the face…. The right hemisphere alone seems to be capable of understanding the more subtle information that comes from the eyes…. It is the right hemisphere that understands the emotional or the humorous aspect of narrative…. It is the right hemisphere that mediates spontaneous facial expressions in reaction to humour or other emotions, including smiling and laughter. It is also the right hemisphere that is responsible for the peculiarly human ability to express sadness through tears…. The left hemisphere has a much more extensive vocabulary than the right, and more subtle and complex syntax. It extends vastly our power to map the world and to explore the complexities of the causal relationships between things…. The superiority of language stems from its nature as the hemisphere of representation, in which signs are substituted for experience…. The right hemisphere plays a vital part in language, too. It uses language not in order to manipulate ideas or things, but to understand what others mean…. It is therefore particularly important whenever non-literal meaning needs to be understood - practically everywhere, therefore, in human discourse, and particularly where irony, humour, indirection or sarcasm are involved…. The right hemisphere represents objects as having volume and depth in space, as they are experienced; the left hemisphere tends to represent the visual world schematically, abstractly, geometrically, with a lack of realistic detail, and even in one plane…. The left hemisphere exhibits a strong tendency to confabulate: it thinks it knows something, recognises something, which it doesn’t, a tendency that may be linked to its lack of ability to discriminate unique cases from the generalised categories into which it places them…. The left hemisphere needs certainty and needs to be right. The right hemisphere makes it possible to hold several ambiguous possibilities in suspension together without premature closure on one outcome. The right prefrontal cortex is essential for dealing with incomplete information and has a critical role to play in reasoning about incompletely specified situations…. The self as intrinsically, empathically inseparable from the world in which it stands in relation to others, and the continuous sense of self, are more dependent on the right hemisphere, whereas the objectified self, and the self as an expression of will, is generally more dependent on the left hemisphere…. The unconscious, while not identical with, is certainly more strongly associated with, the right hemisphere.” The right and left side might work in conjunction with each other, but there is a clear tension between the two hemispheres in each human brain.

After sketching the basic functions, McGilchrist continues by exploring how each hemisphere interacts with language, music, and truth. He suggests that music has ancient origins, even predating language. In prehistoric society, music played an integral role in religion, ritual, celebration, and in uniting the community. It was not passively experienced, but as shared-performance, binded the people in a single experience. Poetry also evolved before prose. “Most forms of imagination, for example, or of innovation, intuitive problem solving, spiritual thinking or artistic creativity require us to transcend language.” Words influence our perceptions, but thinking evolved prior to language. “What language contributes is to firm up certain particular ways of seeing the world and give fixity to them…. Language may not, after all, have originated in a drive to communicate - that came later - but as a means of mapping the world…. It is a means of manipulating the world…. Language enables the left hemisphere to represent the world ‘off-line’, a conceptual version, distinct from the world of experience, and shielded from the immediate environment, with its insistent impressions, feelings, and demands, abstracted from the body, no longer dealing with what is concrete, specific, individual, unrepeatable, and constantly changing, but with a disembodied representation of the world, abstracted, central, not particularised in time and place, generally applicable, clear and fixed. Isolating things artificially from their context brings the advantage of enabling us to focus intently on a particular aspect of reality and how it can be modeled, so that it can be grasped and controlled.” The right hemisphere plays with metaphor. “Everything has to be expressed in terms of something else, and those something elses eventually have to come back to the body…. Metaphor embodies thought and places it in a living context…. Language originates as an embodied expression of emotion.”

McGilchrist begins to show how the functions of each hemisphere have consequences for how humans interact with the outside world. “Attention is a moral act: it creates, brings aspects of things into being, but in doing so makes others recede.” He posits that philosophy in the Western tradition is a left hemisphere process. “It is verbal and analytic, requiring abstracted, decontextualised, disembodied thinking, dealing in categories, concerning itself with the nature of the general rather than the particular, and adopting a sequential, linear approach to truth…. [After all,] manipulation and use require clarity and fixity, and clarity and fixity require separation and division…. According to the left hemisphere, understanding is built up from the parts; one starts from one certainty, places another next to it, and advances…. It conceives that there is objective evidence of truth for a part outside the context of the whole it goes to constitute. According to the right hemisphere, understanding is derived from the whole, since it is only in light of the whole that one can truly understand the nature of the parts…. The left hemisphere is always engaged in a purpose: it always has an end in view, and downgrades whatever has no instrumental purpose in sight. The right hemisphere, by contrast, has no designs on anything. It is vigilant for whatever is, without preconceptions, without predefined purpose…. The right hemisphere is the primary mediator of experience, from which the conceptualised, re-presented world of the left hemisphere derives, and on which it depends…. The left hemisphere does not itself have life…. The means of argument - the three Ls, language, logic and linearity - are all ultimately under left-hemisphere control…. Its point of view is always easily defensible, because analytic…. The left hemisphere builds systems, where the right does not. It therefore allows elaboration of its own working over time into systemic thought which gives it permanence and solidity…. The existence of a system of thought dependent on language automatically devalues whatever cannot be expressed in language…. The left hemisphere is not keen on taking responsibility. If the defect might reflect on the self, it does not accept it. But if something or someone else can be made to take responsibility - if it is a ‘victim’ of someone else’s wrongdoing, in other words - it is prepared to do so.” Imitation is the function of the right hemisphere. Only humans imitate means as well as ends when trying to achieve a goal. Imitation is at root escaping one’s own experience to enter the mind of another. “More empathic people mimic the facial expressions of those they are with more than others…. The process of mimesis is one of intention, aspiration, attraction and empathy, drawing heavily on the right hemisphere, whereas copying is the following of disembodied procedures and algorithms, and is left-hemisphere-based.”

Through the rest of his book McGilchrist posits that, in the Western world, there has been a historical battle between the two hemispheres that has ebbed and flowed through the ages. At first, the right hemisphere was ascendent. “In the Homeric era, the sense of self is intimately bound up with ‘interpersonal and communal dialogue’ in a shared ethical life…. The hiddenness or necessarily implicit quality of Nature requires a particularly alert flexibility on the part of those who go to approach her. ‘Hidden structure is superior to manifest structure’; and openness is required by the seeker of wisdom.” Heraclitus’ philosophy did not turn inward, but sought to carefully study the phenomenal world. “Opposites define one another and bring one another into existence.” However, soon after, the left hemisphere would gain sway. Plato’s “legacy includes the (left-hemisphere-congruent) beliefs that truth is in principle knowable, that it is knowable through reason alone, and that all truths are consistent with one another…. Plato’s belief that knowledge must be unfailing and general led to the position that we cannot know things that are changing or particular.” The ideal forms were all that were worth knowing and striving towards. Ideas about things were prized over the things themselves. Plato particularly disdained poetry, putting in Socrates’ mouth, “all the poets from Homer downwards have no grasp of reality but merely give us superficial representation.” Hans Peter L’Orange writes that this trend away from nuance continued in the traditions of the Roman Empire where “there is a movement away from the complex towards the simple, from the mobile towards the static, from the dialectic and relative towards the dogmatic and the authoritarian, from the empirical towards theology and theosophy.” McGilchrist posits this trend furthered with the early Christians, whose “passion is for control, for fixity, for certainty; and that comes not with religion alone, but with a certain cast of mind, the cast of the left hemisphere.”

McGilchrist suggests that in the Renaissance priority begins to shift back to the right hemisphere. Giotto, in the late thirteenth and early fourteenth centuries, is the first painter to employ perspective. “Perspective mediates a view of the world from an individual standpoint.” The Renaissance ushered in an age of more cultural tolerance and plurality. Melancholy was co-mingled with wit and intelligence. Sadness and pleasure were intertwined. This growth in nuance was, to a large degree, countered by Luther’s Protestant Reformation. “The outer world was in itself empty, and therefore the only authenticity lay in the inner world alone…. The Reformation is the first great expression of the search for certainty in modern times.” The literal Word replaced metaphors in the quest for human understanding. This need for certainty continued with the Enlightenment, which replaced Luther’s religion with a secular science of positivism. Rationality imposes an either/or mentality on life. “Whereas reason respects the implicit, the ambiguous, the unresolved, rationality demands the explicit, the clear and the complete.” This trend was in opposition with artistic creation and this tension grew into the Romantic movement. “Art is by its nature implicit and ambiguous. It is also embodied: it produces embodied creations which speak to us through the senses, even if their medium is language, and which have effects on us physically as embodied beings in the lived world.” Max Scheler stated, “For this reason poets, and all makers of language having the ‘god-given power to tell of what they suffer’ [Goethe, Marienbader Elegie], fulfill a far higher function than that of giving noble and beautiful expression to their experiences and thereby making them recognizable to the reader, by reference to his own past experience of this kind. For by creating new forms of expression, the poets soar above the prevailing network of ideas in which our experience is confined, as it were, by ordinary language; they enable the rest of us to see, for the first time, in our own experience, something which may answer to these new and richer forms of expression, and by doing so they actually extend the scope of our possible self-awareness. They effect a real enlargement of the kingdom of the mind…. That indeed is the mission of all true art: not to reproduce what is already given (which would be superfluous), nor to create something in the pure play of subjective fancy (which can only be transitory and must necessarily be a matter of complete indifference to other people), but to press forward into the whole of the external world and the soul.” The Romantic movement was a move back towards the incompatible. Goethe emphasized, “we are, and ought to be, obscure to ourselves, turned outwards, and working upon the world which surrounds us.” McGilchrist suggests the Romantics returned to the theme of childhood again and again as “childhood represents innocence, not in some moral sense, but in the sense of offering what the phenomenologists thought of as the pre-conceptual immediacy of experience (the world before the left-hemisphere has deadened it to familiarity). It was this authentic ‘presencing’ of the world that Romantic poetry aimed to recapture.” Goethe stressed the impermanence of reality when he stated, “the phenomenon must never be thought of as finished or complete, but rather as evolving, growing, and in many ways as something yet to be determined.” Shelley suggested, “poetry lifts the veil from the hidden beauty of the world, and makes familiar objects be as if they were not familiar…. It creates anew the universe, after it has been annihilated in our minds by the recurrence of impressions blunted by reiteration.” The familiar is the realm of the left hemisphere, whereas the unique and particular of the right.

Industrialization, modernity, and post-modernity were each turns back towards the primacy of the left hemisphere. “The world is either robbed of its substantiality, its ‘otherness’, its ontological status as an entity having an independence from the perceiving subject; or alternatively seen as alien, devoid of human resonance or significance…. The more we rely on the left hemisphere alone, the more self-conscious we become; the intuitive, unconscious unspoken elements of experience are relatively discounted, and the interpreter begins to interpret - itself. The world it puts into words for us is the world that words themselves (the left hemisphere’s building blocks) have created…. [We become] modern man as homo consumens: concerned with things more than people, property more than life, capital more than work…. Socialism and capitalism are both essentially materialist, just different ways of approaching the lifeless world of matter and deciding how to share the spoils.” Modern man becomes passive to the world. “An admiration for what is powerful rather than beautiful, a sense of alienated objectivity rather than engagement or empathy, and an almost dogmatic trampling on all taboos, lies at the heart of the modernist enterprise.” There is novelty and shock, as opposed to newness- seeing afresh what one once thought of as familiar. The explicit reigns over implicit meanings. “Originality as an artist (as opposed to as a celebrity or a showman) can only exist within a tradition, not for the facile reason that it must have something by ‘contrast’ with which to be original, but because the roots of any work of art have to be intuitive, implicit, still coming out of the body and the imagination, not starting in (though they may perhaps later avail themselves of) individualistic cerebral striving…. Language makes the uncommon common. It can never create experience of something we do not know - only release something in us that is already there.” In modern society, knowledge has become professionalized. “Expertise, which is what actually makes an expert (Latin expertus, ‘one who is experienced’) would be replaced by ‘expert’ knowledge that would have in fact to be based on theory, and in general one would expect a tendency increasingly to replace the concrete with the theoretical or abstract.” Measurability and quantification become the standards of knowledge. Context could be neglected for general rules. Uniformity and equality become the overriding goals. In art, “metaphor and myth have been replaced by the symbolic, or worse, by a concept.” The world is seen as a collection of objects. However, “certainty is the greatest of all illusions: whatever kind of fundamentalism it may underwrite, that of religion or of science, it is what the ancients meant by hubris.”

“Surfing Uncertainty” by Andy Clark

Clark is a philosopher who specializes in logic and metaphysics. However, this book combines neuroscience and embodied cognition to give a theory of the predictive brain. Clark has coined this process predictive processing and it relies heavily on Bayesian logic. “It is the kind of automatically deployed, deeply probabilistic, non-conscious guessing that occurs as part of the complex neural processing routines that underpin and unify perception and action…. Brains like ours…. are predictive engines, constantly trying to guess at the structure of the incoming sensory array. Such brains are incessantly pro-active, restlessly seeking to generate the sensory data for themselves using the incoming signal (in a surprising inversion of much traditional wisdom) mostly as a means of checking and correcting their best top-down guessing. Crucially, however, the shape and flow of all that inner guessing is flexibly modulated by changing estimations of the relative uncertainty of (hence our confidence in) different aspects of the incoming signal. The upshot is a dynamic, self-organizing system in which the inner (and outer) flow of information is constantly reconfigured according to the demands of the task and the changing details of the internal (interoceptively sensed) and external context.” Our brains are constantly in action, making top-down guesses about the sensory data to learn about our external world. The brain is creating models and then slowly modulating them, based on past experience, to improve future predictions. Crucially, the brain is not a passive system. Action plays a critical role in predictive processing. “Our massed recurrent neuronal ensembles are not just buzzing away constantly trying to predict the sensory stream. They are constantly bringing about the sensory stream by causing bodily movements that selectively harvest new sensory stimulations. Perception and action are thus locked in a kind of endless circular embrace…. [The brain is able to] use action upon the world to reduce the complexity of its own inner processing, selecting frugal, efficient routines that trade movement and environmental structure against costly computation.”

The brain is constantly learning as it is constantly predicting everything that will happen to the body in the next moment, in an ever-rolling cascade. Perception is very near-term top-down prediction modified by the senses. “Prediction error [is] a kind of proxy for any as-yet-unexplained sensory information. Prediction error here reports the ‘surprise’ induced by mismatch between the sensory signals encountered and those predicted…. Perception is indeed a process in which we (or rather, various parts of our brains) try to guess what is out there, using the incoming signal more as a means of tuning and nuancing the guessing rather than as a rich (and bandwidth-costly) encoding of the state of the world.” It is actually our expectations, to a large extent, that determine what we see, smell, and hear. A prediction does not create our sensory world, but it does focus our attention. “Brains like ours are constantly trying to use what they already know so as to predict the current sensory signal, using the incoming signal to select and constrain those predictions, and sometimes using prior knowledge to ‘trump’ certain aspects of the incoming sensory signal itself. Such trumping makes good adaptive sense, as the capacity to use what you know to outweigh some of what the incoming signal seems to be saying can be hugely beneficial when the sensory data is noisy, ambiguous, or incomplete.” Again, the non-passive nature of the brain is crucial. “Action is not so much a ‘response to an input’ as a neat and efficient way of selecting the next input, driving a rolling cycle. These hyperactive systems are constantly predicting their own upcoming states and actively moving about as to bring some of them into being.”

Each percept is constructed with the help of the brain’s priors. These priors influence future expectations in a probabilistic manner. The brain then combines the likelihood of these priors with raw sensory data. “Attention, thus construed, is a means of variably balancing the potent interactions between top-down and bottom-up influences by factoring in their so-called ‘precision’, where this is a measure of their estimated certainty or reliability.” When evaluating sensations, the brain is constantly separating the signal from the noise, using prior knowledge. This process happens through hierarchical Bayesian inference based on precision-weighted guesses at every level. These predictions then influence future action in a proactive fashion. Memory is also crucial in predicting our future. Fernyhough suggests, “if memory is fallible and prone to reconstructive errors, that may be because it is oriented towards the future at least as much as towards the past…. similar neural systems are involved in both autobiographical memory and future thinking, and both rely on a form of imagination.” In the end, perception is the brain’s best guess as to reality. “Perception (rich, world-revealing perception) occurs when the probabilistic residue of past experience meets the incoming sensory signal with matching prediction.”

Prediction allows our bodies to live in the present. As Franklin and Wolpert assert, “delays are present in all stages of sensorimotor system, from the delay in receiving afferent sensory information, to the delay in our muscles responding to efferent motor commands…. we effectively live in the past, with the control systems having access to out-of-date information about the world and our own bodies.” This is overcome by predictive processing. “Forward models provide a powerful and elegant solution to such problems, enabling us to live in the present and to control our bodies…. you treat the desired (goal) state as observed and perform Bayesian inference to find the actions that get you there…. Motor control is, in a certain sense, subjunctive. It involves predicting the non-actual proprioceptive trajectories that would ensue were we performing some desired action. Reducing prediction errors calculated against these non-actual states then serves…. to make them actual. We predict the proprioceptive consequences of our own action and this brings the action about….. ‘Active Inference’ then names the combined mechanism by which perceptual and motor systems conspire to reduce prediction error using the twin strategies of altering predictions to fit the world, and altering the world to fit the predictions.”

Frith makes the case that “our perceptions are fantasies that coincide with reality.” Hohwy suggests, “what we perceive is the brain’s best hypothesis, as embodied in a high-level generative model, about the causes in the outer world…. Conscious experience is like a fantasy or virtual reality constructed to keep the sensory input at bay.” Thus, the human brain is bounded by an external reality. “Prediction-driven learning delivers a grip upon affordances: the possibilities for action and intervention that the environment makes available to a given agent.” The brain is then constantly making its best guess as to what course will reduce prediction error. This might be by modifying its predictions or it might be through acting. This results in “‘affordance competition’ in which…. possible motor responses are being simultaneously prepared, and in which ‘the human brain does not wait for a decision to be completed before recruiting the motor system but instead passes partial information to prepare in a graded fashion for a probable action outcome’…. Such pro-active readiness, to be genuinely useful, must necessarily be multiple and graded. It must allow many possible responses to be simultaneously partially prepared, to degrees dependent upon the current balance of evidence.”

The world that humans perceive is “our world” in that it is the world best understood by humans. “What we perceive is (when all is going well) the structured external world itself. But this is not the world ‘as it is’, where that implies the problematic notion of a world represented independent of human concerns and human action repertoires. Rather, it is a world parsed according to our organism-specific needs and action repertoire.” Humans create and actively modify our own world. Through language “our own thoughts and ideas now become available, to ourselves and others, as potential objects for deliberate processes of attention…. Courtesy of all that material public vehicling in spoken words, written texts, diagrams, and pictures, our best predictive models of the world (unlike those of other creatures) have thus become stable, reinspectable objects apt for public critique and systemic, multi-agent, multi-generational test and refinement. Our best models of the world are thus able to serve as the basis for cumulative, communally distributed reasoning…. Our human-built worlds are not merely the arenas in which we live, work, and play. They also structure the life-long statistical immersions that build and rebuild the generative models that inform each agent’s repertoire for perception, action, and reason.”

“Modern Liberty and Its Discontents” by Pierre Manent

This is a collection of essays written by the French philosopher on the topics of modernity, politics, and religion. Manent was influenced both by Raymond Aron and Leo Strauss and while some essays deal specifically with their thoughts, others focus on the history of philosophy and sociology more broadly. All the essays are connected by the exploration of what it means to be an individual in modern society. Manent writes about the tension of “liberal democracy (necessarily caught between the promotion and the critique of representation, between the emancipation of the individual and the imposition of a uniform rule).” He teases out the dichotomy of liberty and equality that is at the heart of democracy. Man gradually becomes aware of the freedom and responsibilities than modernity brings. “In Tocqueville’s democracy the power of democracy is not the power of man over man, or the power of one party over another, or it is so only very secondarily and provisionally. It is rather the power of man over himself: more and more actions, more and more sentiments, more and more thoughts, come to live under the democratic regime.” One check to this impulse has naturally been the institution of religion. “By its origins and perhaps its essence, it is external to democracy; this is why it can regulate democracy. It says to democratic man’s liberty, to his envy, and to his disordered passions, you will not go any further!” As democratic man has become individuated he has lost his natural social bonds, for better and for worse. The separation of Church and State was not an equal divide. It is “founded on an essential inequality of consents, which gives a decisive advantage to the public institution over the private one. The inequality of the consents demanded or required translates into the essential superiority of the state over the churches in the regime of separation.” Through the social contract man has consented to be ruled by men.

Modernity tried to build a world ex novo. Manent quotes Charles Peguy, the modern State“ is opposed, it runs counter to all the ancient cultures, to all the anciens regimes, to all the ancient cities, to everything which is culture, to all that is a city.” The conception of the city, as either Platonic or Aristotelean ideal of community, no longer has purchase. Modernity has nothing to learn from the past. Or rather, it picks and chooses at its will and leisure. Manent reflects, “we no longer perceive the extraordinary audacity of the original project of establishing the human world on the narrow point of the human will.” Modern philosophy, starting with Machiavelli, became infatuated with the rational will and the science of what was possible. “It is precisely modern humanity that desires to be the sovereign over nature, creator of its own nature.” Democracy has severed itself from past humanity, from tradition, custom, and culture. “The man of the future, man par excellence, is a being without conscience.” Manent, reflecting on Aurel Kolnai, suggests that man would be better served by combining the moral absolutes of his own conscience with the traditions of conservatism. “We are born in and act in a world already structured by institutions, models, achievements, traditions- by traditions, moreover, which do not force us to be “traditionalists,” precisely because we have the good fortune to be heirs to the tradition of rationally criticizing tradition…. It is because there is a natural and necessary tension between the conscientious and the conservative attitudes that the prudent man has to learn how to combine them, to learn that the relative weight of each depends on circumstances and on the agent’s ability to compose and harmonize, judiciously and even stylishly, the various legitimate themes of free conduct. A conscience with a lively sensitivity to universal moral demands but also well aware of political constraints, of ambiguities and conflicts of values and the uncertainties attending action: a conscience which, when it is at odds with the world, does not hurry to condemn the world but takes time to weigh the adversary’s reasons.”

Individual man has often found himself lost at sea, alone, left to his own devices. He has demanded of the political authority that it acknowledges his consent. “The communities to which people belong in the democratic world no longer command them…. The past itself, understood as the community of those who are dead, has lost all authority to command, whether it be in the moral, social, political, or religious sphere, and is no more than a collection of “memorable places” thrown open to historical tourism.” History no longer advises and urges caution. The past is only studied for amusement. Tradition is quaint. “The only vocation that contemporary man recognizes is that of being an individual. Modern man aims to become ever more the author and artist of all his ties- to be always more un-obliged or disconnected.”

Throughout these essays, Manent is at heart a philosopher. “Philosophy is the endeavor, at once heroic and unobtrusive, to keep one’s distance, to refuse one’s adherence to all these interpretations by interposing between them and oneself the small question, What is?” Philosophy is a disposition. “Philosophy is essentially skeptical. It is therefore not a doctrine, system, or view of the world, but a way of life.” Socrates was the philosopher par excellence. “One must act morally, and not think morally.” More so than even romantic love, true friendship guides the path of the philosopher. in the past, the bonds of friendship were desired because they engendered the quest for a common truth in man. The ideal man sought “the life of reason, the life dedicated to understanding life… “The love of wisdom” (philosophy) is literally, and nonmetaphorically, the most erotic of the soul’s dispositions, the one that leads toward its highest possibility and that consequently is capable of forming the strongest human tie because it is the most genuine one…. Life is worthy of being loved because it is capable of being understood.” 

“The Consciousness Instinct” by Michael Gazzaniga

Gazzaniga is the director of the SAGE Center for the Study of Mind at UCSB. His book begins with a historical overview of various speculations on consciousness over the centuries, starting with the ancient Greeks and continuing through Freud and Schopenhauer, before ending with Gazzaniga’s own opinions on the nature of consciousness. Many of history’s earlier claims about consciousness are still relevant as they lay the foundations for modern controversies that still divide the neuroscience community today. Among the prominent theories Gazzaniga reviews are Descartes’ mind/body dualism, Locke’s tabula rasa (blank slate) formulation, which led to Skinner’s behaviorism, and Hume’s chains of perception. John von Neumann was to add to speculations on the workings of neural networks by proposing the idea of parallel organization, where different groups of neurons could run independently and simultaneously. Chomsky supposedly dealt behaviorism a fatal blow with his ideas on a universal grammar, innate in all humans. Gazzaniga and his mentor Robert Sperry were to conduct research on humans whose brains had been surgically split to ease epileptic seizures. Sperry recounted, “everything we have seen so far indicates that the surgery has left these people with two separate minds, that is, two separate spheres of consciousness.” This research laid waste to the idea that consciousness was located in any particular area of the brain or even, in fact, that each human had one unique conscious ‘self’ at all. Sperry felt that “consciousness may have real operational value, that is more than merely an overtone, a by-product, epiphenomenon, or a metaphysical parallel of the objective process.” Sperry leaned towards the idea of emergentism: that “consciousness emerges from unconscious matter once that matter achieves a certain level of complexity or organization.” This is in contrast to the other major materialist idea of panpsychism: that all matter has some type of consciousness within it, albeit with a wide range of both scale and scope. All modern consciousness researchers strive to get at what David Chalmers has labeled “the hard problem” or Thomas Nagel has described as “what it is like” to be something, subjectively. Nagel stated, “an organism has conscious mental states if and only if there is something that it is like to be that organism—something it is like for the organism.” These subjective characteristics of experience have sometimes been referred to as qualia. On the other hand, the philosopher Daniel Dennett disagreed that subjective experience was even a scientific problem/issue. He suggested it was all an ultra-realistic illusion and that the sensation of “‘having an experience’ is beyond the realm of the objective” and thus beyond the realm of science. Gazzaniga’s effort in the rest of his book aims to refute this “new dualism” and tries to fit consciousness within the modern research paradigm of the material brain.

Gazzaniga describes the brain as being separated by independent neural modules. “Modules are specialized and frequently localized networks of neurons that serve a specific function…. The perks of brain modularity are that it saves energy when resources are scarce, allows for specialized parallel cognitive processing when time is limited, makes it easier to alter functionality when new survival pressures arise, and allows us to learn a variety of new skills.” On top of this modular structure of the brain is a layered architecture. “Each layer in a system operates independently because each layer has its own specific protocols, the set of rules or specifications that stipulate the allowed interfaces, or interactions, both within and between layers.” This layered system allowed humans to evolve from simpler life forms, while keeping their lower-level structures and building on top of them, rather than beginning a unified functioning structure from scratch. Therefore, many of our bodily functions, from metabolism to replication, are formed using the same core-processes as that of simpler forms of life, such as bacteria, since we all share the same genomic sequences. This layered architecture evolved because it limits the effects of localized malfunctions, making repair or replacement easier, and making for a more robust, if less efficient, system. “Because each layer can provide a wide range of diverse functions, the system has greater flexibility as a whole, giving it a great advantage when facing a changing environment. This type of layout is ideal in an evolutionary sense because the number of vulnerabilities in the system is limited, while the opportunities for diversification are abundant.” Neural redundancy becomes a feature, not a bug, of this system. Therefore, “there may not be a specific modular hierarchy that allows consciousness to manifest itself in one way or another. Specific modules work relatively independently and, rather than being a neatly ordered queue of modular processing, the contents of our conscious experience may be the result of some kind of competition: some processing takes hold of your conscious landscape at a given moment in time…. The multitude of conscious-producing modules simply diversifies your conscious portfolio…. The modular brain makes consciousness resilient because of the plethora of possible paths that can lead to a conscious moment…. The brain operates in a modular fashion, but it also suggests that independent modules can each produce a unique form of consciousness.”

Gazzaniga feels that consciousness research could learn a great deal from quantum physics, particularly the idea of complementarity: that matter, such as electrons, can have both particle-like and wavelike properties. There is both the macro-world of Newtonian physics and the micro-world of quantum physics, in which the same matter behaves by different laws, all at once. Particular to quantum mechanics is the idea that the observer matters. He affects the system by his very observation of it. Any measurement requires an observer who is separate from the object measured. “The measurement itself may be precise and objective, but the process of measurement is subjective.” Gazzaniga suggests that “human consciousness was way too high a layer in the architecture of all living organisms to put the epistemic cut between the observer and the observed, between the subjective experience and the event itself.” The key to consciousness might begin with the difference between the living and the lifeless. He quotes Howard Pattee, “I have taken the point of view that the question of what constitutes an observation in quantum mechanics must arise long before we reach the complexity of the brain. In fact, I propose…. that the gap between quantum and classical behavior is inherent in the distinction between inanimate and living matter…. Our models of living organisms will never eliminate the distinction between the self and the universe, because life began with this separation and evolution requires it…. This is a universal and irreducible complementarity. Neither model can derive the other or be reduced to the other.” Gazzaniga suggests that these “two complementary modes of behavior, two levels of description are inherent in life itself, were present at the origins of life, have been conserved by evolution, and continue to be necessary for differentiating subjective experience from the event itself.” William James had suggested the idea of polyzoism: that “every brain-cell has its own individual consciousness, which no other cell knows anything about, all individual consciousness being ‘ejective’ to each other.” Gazzaniga suggests that each cell has a very rudimentary conception of the subjective ‘self’, built on the fact that each cell has semiotic closure, the key to independent living systems present in all cells. He continues, “neural circuits are structures with a double life: they carry symbolic information, which is subject to arbitrary rules, yet they possess a material structure that is subject to the laws of physics.” Gazzaniga suggests that consciousness is the linkage of independent neural modules that span across time and memory. “Each mental event is managed by brain modules that possess the capacity to make us conscious of the results of their processing…. Those single bursts of processing parade one after another, seamlessly linked by time…. Our smoothly flowing consciousness is itself an illusion. In reality it is made up of cognitive bubbles linked by subcortical “feeling” bubbles, stitched together by our brain in time…. Consciousness is inherent throughout the brain.”

“The Mind is Flat” by Nick Chater

Chater is a professor of Behavioural Science at Warwick Business School. His book seeks to explode the myth of the unconscious mind. He suggests that humans do not have thoughts below the mind’s surface waiting to bubble up. Humans “generate our beliefs, values, and actions in-the-moment; they are not pre-calculated and ‘written’ in some unimaginably vast memory store just in case they might be needed…. Introspection is a process not of perception but of invention: the real-time generation of interpretations and explanations to make sense of our own words and actions.” Chater suggests that we know less than we think we know. Therefore, we make up explanations ex post and ad hoc. If we are asked to explain how a bicycle, a zipper, or a thermostat work, most humans find that they only have an illusory conception of the details. This improvisational quality to explanations is referred to as ‘the illusion of explanatory depth’, which is the “contrast between our feeling of understanding and our inability to produce cogent explanations.”

The mind is not a mirror onto the world. It does not store a picture of all its surroundings to be summoned up at will. Instead, when taking in a scene from the outside world, “the brain ‘grasps’ different aspects of the image at different times…. Our brain glimpses, and conceives of, the world fragment by fragment.” Our field of vision is actually quite narrow with our peripheral vision exceedingly blurry. Also, studies have shown that our eyes can take in only one color at a time, before rapidly moving on to the next color in the field. This lack of perceptual depth is true even with mental images. “Our imagination, like visual experience, is a narrow window of lucidity, and what we see through that window is invented — creatively, subtly, intelligently — not merely reported from some fully specified, entirely coherent inner world.” When we are asked to imagine the image of a tiger or a cube upon a table most often we forget to include details such as the direction of the tiger’s stripes or the shadow the cube creates on the surface, until later asked about them when we quickly fill those into our previous mental picture. “We are not examining a fully formed, comprehensively detailed and coloured mental image in our mind’s eye — at one moment zooming in, or shifting our attention to the left and right. We are, instead, creating our mental image, piece by piece, moment by moment, touchpoint by touchpoint.” This is why our dream world seems so disjointed. “Dreams seem to be naturally viewed as the successive creation and dissolution of momentary fragments; in retrospect full of holes and contradictions…. Scenes and even time itself shifts abruptly, people change identities, and appear and disappear without warning…. There is no careful author painstakingly attempting to bring the story into some kind of order — merely a succession of capricious imaginative leaps…. We haven’t forgotten these details; our brain never bothered to specify them in the first place…. Dreams are improvised stories, with few details sketched in. When our minds create them, we lock onto some specific fragments of information; almost everything else is left entirely blank.” This is the same with our daytime thoughts. “Our thoughts are not shadows of an alternative inner reality, to be charted and discovered; they are fictions of our own devising, created moment by moment.”

The brain also invents feelings and emotions based on external clues, sensory inputs, and our own interoceptive system. “The brain interprets each piece of perceptual input (each face, object, symbol, or whatever it may be) to make as much sense as possible in the light of the wider context.” The background details of a photograph will widely change how we interpret the emotions on the photo’s face close-up. Context fuels the imagination. Often, even our own emotion is cued by external context. In psychological experiments, a shot of adrenaline induced either anger or euphoria depending on the external stimuli in the room. “It seems that we are figuring out what emotion we must be experiencing, and doing so, in part, from the state of our own body. We tend to imagine that our emotions well up from within, and cause physiological reaction…. But in reality it seems that we are figuring out what emotion we must be feeling, partly based on observing our own physiological state.” We interpret our interoceptive system based on external clues and then latch onto the emotion that best fits the combined situation. “Having an emotion at all is a paradigmatic act of interpretation, and hence of reasoning.”

The brain’s capacity is constrained by its neural networks. Chater suggests that each interconnected group of neurons can only interact with a single problem at a time. “The brain works by cooperative computation across most or all of its neurons — and cooperative computation can only lock onto, and solve, one problem at a time…. The unconscious cannot be working away on, say, tricky intellectual or creative challenges, while we are consciously attending to some other task — because the brain circuits that would be needed for such sophisticated unconscious thoughts are ‘blocked’ by the conscious brain processes of the moment…. Consciousness, and indeed the entire activity of thought, appears to be guided, sequentially, through the narrow bottleneck: sub-cortical structures search for, and coordinate, patterns in sensory input, memory and motor output, one at a time. The brain’s task is, moment by moment, to link together different pieces of information, and to integrate and act on them right away.” The brain processes the vast amounts of incoming sensory data, but then quickly focuses its attention, discarding all that is irrelevant. “Our brains lock onto fragments of sensory information, and work to impose meaning on those fragments. But we can only lock onto and impose meaning on one set of fragments at a time…. The brain will initially find some basic ‘meaning’ to help pin down which information is relevant and which is not…. As the brain’s processing step proceeds, the effort of interpretation will narrow ever more precisely on the scraps of information that helped form whatever pattern is of interest, and the processing of other scraps of information will be reduced and, indeed, abandoned.”

The brain is so interconnected that it can, most often, only do one thing well at a time. “People could do two things at once when distinct mental calculations — presumably associated with non-overlapping networks of neurons — were involved (e.g. for sight-reading music and taking dictation). And such specialized brain networks can sometimes be developed for highly practised and repetitive tasks.” Even when walking and thinking, people tend to slow their pace when a challenging or novel thought enters their brain. Chater suggests that unconscious thought is a complete myth. The brain is never working away on problems in the background for them only to flash into consciousness when fully formed and worked out. “There is absolutely no sign that we can search for xs when we are currently thinking about ys, or search for ys, when we have been thinking about xs. As soon as we switch from searching one category to searching another, all search processes for that first category appear to cease abruptly.”

Importantly, Chater suggests that there is a neural background that does form an unconscious, but it is not comprehensible, even to our own minds. “The neural processes within each cycle of thought are, crucially, not the kind of thing that could be conscious. They are, after all, hugely complex patterns of cooperative neural activity, searching for possible meanings in the current sensory input by reference to our capacious memories of past experience. But we are only ever conscious of particular interpretations of current sensory input…. We are conscious of, and could only ever be conscious of, the meanings, patterns and interpretations that are the output of this cooperative computation…. Our conscious experience is determined by what the brain thinks is present — the output of the cycle of thought, not its input.” This flow between the brain and sensory input is a two way street that results in predictive processing where some inputs are neglected by neural predictions, which highlight only the relevant information. “Perception, then, is a process of incredibly rich and subtle inference — the brain is carefully piecing together the best story it can about how the world might be, to explain the agitations of its sense organs. Indeed, attempts to interpret sensory input, language or our own memories typically involve inference of great subtlety to figure out which ‘story’ weaves together the data most compellingly…. Perception requires puzzling out the significance of a set of clues, each of which has little significance when considered in isolation.” Therefore, “mental processes are always unconscious — consciousness reports answers, but not their origins.” The brain was constructed, evolutionarily, to relay back to its owner the world as it really is, not the plethora of its inputs how they come in. “In order to decide how to act, we need to know what the world is like; our brains don’t care about the complex process of gathering and knitting together our stable world…. Our sense that seeing and hearing seem continuous arises because the brain is informing us that the visual and auditory worlds are continuous; and subjective experience reflects the world around us, not the operations of our own minds.” There is nothing more withheld within our brains than our own consciousness. “Our conscious experience consists of organizations of the surface of our sensory experience, whether conjured up through perception, imagination, or memory…. We consciously experience the sensory information, broadly construed (including images generated by our own minds; sensations from inside our bodies, such as pain, feelings of exhaustion or hunger; and crucially from inner speech).”

The brain uses past memories to interpret present perceptions. “We layer each momentary thought on top of past momentary thoughts, tracing an ever-richer web of connections across our mental surface…. The interpretation of each everyday scene depends on a vast hoard of past interpretations of everyday scenes. Indeed, perception works by relating, often in the most flexible and creative fashion, our sensory input with our memory of past experience. We do not interpret every sensory impression afresh, but in terms of the memory traces of past sensory impressions.” Importantly, memory stores past interpretations of inputs, not the raw inputs. Therefore, the past that was not deemed necessary to be interpreted is also not remembered. “Today’s memories are yesterday’s perceptual interpretations.” This creates a continuity of thought within the brain. “Our mental life follows channels carved by our previous thoughts, and traces of our present thoughts and actions will shape how we think and act in the future…. We do, after all, possess some inner mental landscape. But this is not an inner copy of the outer world or, for that matter, a library of beliefs, motives, hopes or fears; it is, instead, a record of the impact of past cycles of thought.” 

Metaphor is critical for our interpretation of the world. “Our continual search for meaning is the struggle to find patterns in our present experience, in the light of the past. And so we see one thing in terms of another…. Metaphors, too, are also employed to impose meaning upon one aspect of the world, by drawing on an understanding of another.” It is not that the brain does not have unconscious processes, it is simply that they cannot be accessed to become conscious. There is not a vast store of mental thoughts bubbling below the surface. There are only the inchoate inputs from which the brain creates the only thoughts that it has at all- conscious experience.