Archive for the ‘Neuroscience and Psychology’ Category

Oliver Sacks – The Man Who Mistook His Wife for a Hat

[Public Service Warning: These posts on books are generally too long to be good reviews or blog posts, and too scattered. I put them here mostly as reading notes for myself, in the absence of a good system of keeping track of things read and thoughts had. But I figure they might as well be public–no harm in it, anyhow.]

I’m very sympathetic to Oliver Sacks: as a writer, I have a soft spot for narratives in science. And I’d always like to think that science can help us speculate on the Big Questions, so I’m intrigued when Sacks muses on issues of identity and the soul in the midst of these case studies. And even though his philosophy is lacking much of the time, I tend to enjoy that he tried, and take his speculations for what they are: wishful, though earnest, musings; philosophy lite meant to point out a direction more than travel a rabbit hole.

So, I deeply enjoyed these vivid case studies, and I found them instructive too–even when I groaned a little at the misinterpretation of Hume, the use of Wittgenstein as a glossy epigraph only, or the grandiosity of adding a page-long postscript on the nature of the soul to a simple neurological case study. And even though Sacks’ love of smart people grated (If I hear “there didn’t seem to be anything wrong: he was a man of great cultivation and charm” or any variant, ever again…), I suspect that there would be no Sacks as we know him without it–that same love drives him to explore the subtleties and varieties of how intelligence and the creative, remembering mind present.

Some studies that stood out:

*The recurring musings on time and memory occasioned by patients with various kind of aphasia. From Luis Bunuel:

“You have to begin to lose your memory, if only in bits and pieces, to realize that memory is what makes our lives…Our memory is our coherence, our reason, our feeling, even our action. Without it, we are nothing…(I can only wait for the final amnesia, the one that can erase an entire life, as it did my mother’s…)”

—Jimmy, who remembers his early life vividly, and speaks of it like the present: uses “not just the formal or fictitious present tense of recall, but the actual present tense of immediate experience.” (24) Sacks’ examination of him is illuminating: he tests what memory loss there is by asking him to write down the names of three objects Sacks has just hidden, and thereby pinpoints exactly how many seconds the memory loss entails. He asks about how many elements there are and how many planets to locate Jimmy in memory-time. He can tell that there are faint echoes of recent memories in Jimmy from how Jimmy remembers “some doc” tested him, though not what he was just asked to do in the test. Chess is too slow of a game for him to play it; checkers is fine.

“My note was a strange mixture of facts and observations, carefully noted and itemissed, wit irrepressible meditations on what such problems might ‘mean,’…I kept wondering, in these and later notes–unscientifically–about a ‘lost soul,’ and how one might establish some continuity, some roots.” (29) He brings in Luria’s account of Korsakov’s and Studs Turkel’s account of The Good War to make sense–unscientifically–of Jimmy’s experience. He reconstructs Jimmy’s life from hospital admission records and his brother’s reports. He makes the crushing bedside mistake of asking Jimmy how it can be himself, who looks so old, in the mirror.

Luria and Sacks write–they always write each other–and Luria advises, “There are no prsecriptions in a case like this. Do whatever your ingenuity and your heart suggest…But a man does not consist of memory alone. He has feeling, will, sensibilities, moral being–matters of which neuropsychology cannot speak And it is here, beyond the realm of an impersonal psychology, that you may find ways to touch him, and change him. And the circumstances of your work especially allow this, for you work in a Home, which is like a little world, quite different from the clinics and institutions where I work.”

What to do for Jimmy? Sacks asked the Sisters if he had a soul still–they said, “watch him in chapel and see.” He saw intensity, steadiness of attention.  “Seeing Jim in the chapel [he calls him Jim now, more dignified, not kiddie] opened my eyes to other realms where the soul is called on, and held, and stilled, in attention and communion.” “He was perfectly organized in Bergsonian ‘intentional’ time; what was fugitive, unsustainable, as a formal structure, was perfectly stable, perfectly held, as art or will.” (38)

**The eponymous man, who sees features of an image but not the whole, the abstract–and seemingly makes up features that aren’t there, when questioned, without knowing he’s doing so. He can also process schematic, abstract things (playing cards, Platonic solids, cartoons once he’s picked an identifying feature–but not the faces of people he knows, unless they have a memorable outstanding feature. He calls a rose: About six inches in length; a convoluted red form with a linear green attachment.” (12) He has no trouble with auditory or olfactory stimulus identification, and he can recognize objects that he’s using.

**Christina, who has a dream about losing proprioception and then does, after the surgery. She compensates with learning physiology and LOOKING at every body part as she moves it: so she slowly learns to move again, but only when she can give it her undivided attention. She feels “her body is blind and deaf to itself”–she still feels disembodied, not-her. Sacks found hundreds like her later: all taking an overdose of vitamin B6.

**A woman with CP who hasn’t used her hands in 60 years: the sensations are all there, but no perception–she feels pain, heat, movement, but can’t recognize any object put in her hands. She’s highly verbal and literate – people have been talking to her for 60 years. The “dead” feeling is paralleled by electrical silence in the relevant nerves. When she’s pushed a little, though, by impulse she was induced to use her hands–food kept just a little bit out of reach. She starts out recognizing forks as a flat thing with tines–then suddenly intuits its organic objecthood and use. Then she became highly animated with her hands, and known locally as “The Blind Sculptress of St. Benedict’s.” The idea of “developmental agnosia,” and the ability to learn at 60 what most learn at 2.

**Mr. MacGregor, who diagnoses himself after seeing a video of him walking “on the tilt”: “is there a kind of spirit level in the brian, Doc? Can it be knocked out by Parkinson’s” – Sacks: “the picture I love to see: a patient in the actual moment of discovery–half-appalld, half-amused–seeing for the first time exactly what is wrong, and, in the same moment, exactly what there is to be done.” (72) The work of Purdon Martin on Parkinson’s patients in The Basal Ganglia and Posture, Martin “endlessly thoughtful and ingenious in designing a variety of mechanisms and methods…to achieve an artificial normality of gait and posture: lines painted on the floor, counterweights in the belt, loudly ticking pacemakers–to set the cadence for walking. In this he always learned from his patients…” They together design a literal level protruding from the bridge of his glasses, and he learns to use it.

**Patients who just seem to stop knowing the left side of the world exists: the image of a patient spinning around in her chair, always to the right, bisecting her portion each time so she can get most of it even though she can see but half at a time. Zeno’s patient.

**Agnosias and people who can detect what Head calls “feeling tone,” and thus, one feels, can’t be lied to. (Note: I first heard this term from Studs Terkel’s Division Street…)


**”Witty Ticcy Ray,” about Tourette’s. Sacks locates the disappearance of talk about Tourette’s in “the turn of the century, a split had occurred, into a soulless neurology and a bodiless psychology”–some doctors thought of Tourette’s as mythical. The integral role of the Tourette’s Syndrome Association, formed by patients, in driving research into Tourette’s: genetic and developmental factors, the associations and reactions that characterize it, evolutionary basis, the body-language, grammar and linguistic structure of tics, the role of cursing and joking in various neuropathologies. The disturbance is in the highest parts of the “old brain,” whereas in Parkinson’s–which leads to excesses of motion but not action–it’s in the midbrain. Many Tourette’s sufferers are also great improv musicians. Luria saw Tourette’s as the most interesting disease for a window into human nature. Being free from tics when engaged in some other “kinetic melody.” He could only take Haldol well after being “prepared” for life without Tourette’s in therapy–after coming to believe there was a self to him beyond the disease. And now he only takes it on weekdays: he needs the Tourette’s self for his music on weekends, needs to “let fly.”

—Doing “street neurology” to see the severest forms of Tourette’s, the imitator’s. Naturalistic studies: Meige and Feindel’s Tics, Rilke’s portrait in the Notebook of Malte Laurids Brigge. A woman who mimics and caricatures all passers-by, each for a few milliseconds, doing a kind of frenzied dance that draws crowds around her (which only makes the ticcing worse, giving her more to imitate).

**The Korsakov’s patient, with amnesia, who is always chattering and “making up” stories–his brother walks by, and he says “and there’s my brother” in the same easy tone–it takes the docs a while to realize that this part is true. Only finds peace in the garden, away from people with whom he feels pressure to be the comedian and tell stories. Doesn’t exhibit a sense of being “lost” or realization of the lack of inner feeling.

**Mrs. O’C, who heard Irish songs in her head constantly, clearly, when none were playing. She was having temporal lobe seizures–that got less intense after a few days: in the beginning, she couldn’t “hear” over the music. Another, Mrs. O’M, who had 3 songs she didn’t like on repeat in her brain, and who was developing amusia too–all the hymns in church started to sound the same. Hughlings Jackson on the strange phenomenon of a musical epilepsy: “It is not very uncommon for epileptics to have vague and yet exceedingly elaborate mental states at the onset of epileptic seizures…The elaborate mental state, or so-called intellectual aura, is always the same, or essentially the same, in each case.” Experiential hallucinations. A duality of perception–“I know you’re there, Dr. Sacks. I know I’m an old woman with a stroke in an old people’s home, but I feel I’m a child in Ireland again.” Always memories, these, never fantasies, according to Wilder Penfield’s studies. Why the preponderance of MUSICAL memories? Penfield calls them random–but “we know from the stud of ‘free associations’ tha the most seemingly trivial or random thoughts may turn out to have an unexpected depth and resonance, but that this only becomes evident given an analysis in depth.” Mrs. O’C’s seizures gave her back memories of a lost childhood: though she doesn’t remember the details now, she feels a sense of completeness and groundedness now that she didn’t before. [See Esther Salaman, A Collection of Moments, and Dostoyevsky on his seizures. Also see Penfield and Perot, “The Brain’s Record of Visual and Auditory Experience.” See also reviews of vision studies, older–David Marr 1982–and recent–Ramachandran.]


“Let us note…that the removal of the minute, convulsing point of cortex…can remove in toto the iterating scene, and replace an absolutely specific an equally specific oblivion or amnesia. There is something extremely important, and frightening here: the possibility of a real psycho-surgery, a neurosurgery of identity (infinitely finer and more specific than our gross amputations and lobotomies, which may damp or deform the whole character, but cannot touch individual experiences.” (148)

Central question for Sacks here: “Thus a gulf appears, indeed a chasm, between what we learn from our patients and what physiologists tell us. Is there any way of bridging this chasm? Or, if that is (as it may be) categorically impossible, are there any concepts beyond those of cybernetics by which we may better understand the essentially personal, Proustian nature of reminiscence of the mind, of life? Can we, in short, have a personal or Proustian physiology, over and above the mechanical, Sherringtonian one?” Sherrington calls the mind “an enchanted loom,” weaving patterns of meaning.

In high school, I was fascinated by the brain and neuroscience. But I realized at some point that I had lots of questions and no idea of how I wanted them answered–I didn’t think “memories originate in the hippocampus” would be sufficient, nor is the more refined geography of the brain we now have a map to. Sacks points towards the types of answers I realized I’m interested in–must follow up on more recent science and see what’s going on in this vein of Hughlings Jackson, Luria and Sacks, and how much of this is real speculation.



Oliver Sacks: A Leg to Stand On

January 8, 2012 Leave a comment

I love Sacks’ project, following Luria, of a “romantic science,” what we might now call “humanistic medicine.” His and Luria’s essays are some of my favorite and most memorable reading, ever. But there’s something that’s always puzzled and unsettled me about Sacks: I’m always left with the suspicion that he doesn’t have a lot of empathy for his patients. Now, I have no sense of Sacks as a clinician (I’ve never read a single thing he’s written for medical circles), and I’m not among those who criticize him for “exploiting” his patients as interesting stories to sell books with. Still, he uses a language of virility and health-as-virtue that doesn’t sit easily with his “romantic science” project for me.

The first hint of this for me is in “A Leg to Stand On,” with the curious disjunction between his articulateness in describing his own experiences and his compete unfamiliarity with the feeling of unexpected helplessness that comes with being a patient (“I wanted to pursue the point, but there was something in their tone and manner that made me desist. I felt curiously helpless…and I thought, ‘Is this what being a patient means?'” — pg. 47) Can he really be so surprised by this feeling after 15 years of working with patients? As a patient, I remember thinking that kind of thought before I was ten years old…surely one who puts such emphasis on the human side of medicine should understand this basic thing?

Yet he does understand something of the human side of medicine–the soul, the spirit, the whirling thoughts, the demotion of the reasoning faculty even in one such as him. When he’s narrating his stream of consciousness, it’s poignant, like in: “Secretly, half-skeptically, hesitantly, yearningly, I addressed myself to this unimaginable ‘Thou’ [of the Psalms].” (p. 115) I enjoy his meditations on Leibniz and Nietzsche and the Metaphysicals on the nature of the soul, and I even think those were the thoughts that were swirling in a learned head like his. And maybe Sacks has exaggerated his breezy sense of virility when he opines on things like, “I forged ahead, keeping up a brisk pace despite the gradient, blessing my energy and stamina…Strong quads, strong body, good wind, good stamina–I was grateful to Nature for endowing me well.” (p. 19) But he pulls these moves repeatedly: seeming to like his witty patients better (he talks in “The Man who Mistook…” about how he dreaded working with patients with MR), calling people simpletons in what doesn’t seem like just the normal language of the time, describing his own world in epic terms and relating his case histories with some of the air of a freak show, or at least an “interesting phenomenon” that offers a chance for Sacks to indulge in grandiose reflection. Sometimes I like those wildly speculative moves–but the ego behind them can drive me  a little crazy. And the condescension he gets away with by applying it to himself too (his former self, his sick self, not the “real” one): He takes the healthy idea of a place to have a peaceful interlude before entering harsh reality again and makes it into something distasteful: “If we could not face the world, the world could not face us, with our lineaments, our habiliments, of sickness and affliction. We inspired horror and fear…and for the world’s sake, no less than our own, could not be let out.”

But there are little sympathetic moments. His description of the Convalescent Home is rich and profound in its new understanding of the community of patients, and he puts better than I many themes that I see recur in my own writing on patienthood. There’s his recollection of “the summer of 1938, [when] I discovered that the whorled florets were multiples of prime numbers, and I had such a vision of the order and beauty of the world as was to be a prototype of every scientific wonder and joy I was later to experience.” (p. 34) Or when he describes having the distinct feeling that the little tiny village church below was playing the Mozart Requiem as he thought he was dying, or when he ecstatically speculates, “I felt…that life was itself music, or consubstantial with music; that our living moving flesh, itself, was ‘solid’ music…was music, I wondered, the very score of life–the key, the promise, of renewed action and life?” (119)

The flights of intellect are dazzling–but only as character-pieces. A lot of the science is outdated, and the philosophy wrong: Hume doesn’t treat the self as nothing but a bundle of momentary impressions. We recognize many mental illnesses among the seemingly well now. No, in a sober state, we can’t say music is the key to health, though it makes some strong claims to centrality. Some of it is outdated through no fault of Sacks’: we have a much better neurological understanding of “free will” and ideomotor responses now. And for all the self-congratulation, there’s the childish sense of wonder, adventure and delight that lets us excuse it, brush it off as not posturing: when he hears back from Luria, we share his excitement and don’t notice the hubris: “If such a thing happens it can only be understood, and used. Perhaps it was your destiny to have the experience; certainly it is your duty now to understand and explore…Really you are opening and discovering a new field.” (197)

And finally, the beginnings of his journey towards a “romantic [neuro]science” is thrilling. Reading Head on the train and noticing the dual language of neurology and poetry (sequence/series/complex procedures vs. wholeness/completeness/ perfection/melody), Sacks’ memory of his father saying of Head “He was the most rigorous of scientists, but he was a poet too. He felt the music of movement and speech, but as a neurologist he could not explain it.” The conflicting passions for theory and life.

I don’t agree with the cult of experience (“you can only know what you’ve experienced,”) but if it made Sacks a better doctor, so much the better. The book ends with the beginning of a humbling and exciting journey for Sacks, back to the case studies of Weir Mitchell and around the margins of the neurological literature in search of the descriptions that are “known to hundreds of thousands of patients, but entirely unknown in the medical literature,” the “early days” that are unspoiled by concepts.

Sacks asks doctors to forget their neurological studies and terms for a moment, to pay attention to the singularity of patients’ descriptions in their own words. I love him for that. He is a little too quick to draw shaky metaphysical implications from his case studies; maybe he bends the stick too far; but his project is a sympathetic one, and it’s easy to cut him slack. I wouldn’t take this as good science–but it’s a good vision.

And there’s further reading in neuropsychology to be had in this vein. Noting that Luria and Head both were themselves the humanizing forces in their new neuropsychology (and their texts are still of the “mechanical” sort), Sacks goes further with the idea (as much Leontev’s and Zaporozhets’ as Luria’s) of the “science of doing,” observation in natural environments and the study of the whole system.

Sacks is disenchanted with a Hume he invents, one who sees nothing of the self or soul behind the perceptions. But this nonetheless leads him in wonderful directions, pursuing a “neurology of the soul” that takes on the existential questions too. I’ll get to his success in an empirical way later when I discuss the case histories in “The Man who Mistook his Wife for a Hat”–but for now, let’s leave with the exchange of “music is the solution!” between Sacks and Auden, and the universal image of a transformative ecstatic experience, having discovered new vistas, while stepping off the train with two bulky volumes under arm. We all have to find our ways to come back from that land of transformation and art to the quotidian of the living.

But for now, I’m off to discover Darwin the father in his Biography of an Infant and brush up on Kant and Hume to see how Sacks’ philosophy checks out. Might make a stop by Weir Mitchell too, and see what I can dig up on Auden and Sacks. Can always count on Sacks for an inspiring reading list.

Reading Lessons from Dehaene

October 1, 2011 Leave a comment

I just finished reading Stanislas Dehaene’s Reading in the Brain, and I’m already scrambling to figure out how I’m going to pitch it to the several people in wildly different areas who I think will find it fascinating. The book has two mutually supporting strengths that make for only a rare dull moment: meticulousness and willingness to speculate on the questions that really matter to us.

The basic claims underlying Dehaene’s neurological work are meticulously and transparently backed up with oodles of experimental results from different labs and different schools of neuroscience. Some of the details are really nitty-gritty ones, but I’m left with little doubt about the validity of his main claims vis a vis the brain: that it has a “letterbox” region that activates during reading only and is culturally invariant, and that this region is divided into cortical areas that together demonstrate a neurological basis for the psychologist’s model of top-down and bottom-up, hierarchical networks of visual processing that allow us to read.

In particular, Dehaene outlines a slow grapheme-to-phoneme route for decoding and a lexical route that develops eventually in expert readers, and describes how such things as invariant processing of multiple fonts and sizes and levels of abstraction in feature detection can arise from networks of neurons operating in parallel, the “bottommost” ones in the tree coding for line segments presented on the retina, middle ones that act as letter-detectors, and top ones that code for entire words. This perhaps wishy-washy model based on potentially naive neural network models that are currently in vogue is backed up with exhaustive anatomical information that confirms that these types of neurons do in fact exist in the “letterbox area,” the left occipito-temporal cortex, and they behave in a way consistent with the model. Further, this letterbox is culturally acquired and specific: Hebrew words don’t activate the letterbox area for English readers.

More surprising is the precision of this correspondence between written language categories and the letterbox’s division: there seem to be particular areas that code for different categories of words, within the area of the letterbox that processes meaning: different cortical regions for faces, people, animals, etc. And within verbs, the area of the premotor cortex that maps to the particular body part in question is activated when reading the verb: so reading “kiss” activates the area for the mouth, reading “kick” activates the area for the leg–words literally activate the motor areas they refer to. So the image of reading in the brain is simultaneously extraordinarily specific–as the reader learns, the cortical areas begin to be more and more subdivided and specialized in what they react to (one model of what learning looks like in the brain in general)–and extraordinarily diffuse, with the letterbox area connecting to the corresponding region in the other hemisphere, to the frontal cortex where we “synthesize” ideas and inputs, and all around the brain.

Dehaene is exacting about his brain science: he describes in detail what PET, fMRI, diffuse MRI, and magnetoencephalography (direct tracking of cerebral activation on the cortical surface itself, which lets us make movies in slow motion that show how a single read word travels through the brain) and lesion analysis have told us about the brain’s functioning, and what their limits are. But for me, the most interesting science was the slightly more speculative stuff, which came in (1) the research that indicates how the brain comes to specialize in reading for expert readers (development), and (2) the comparative studies of the region corresponding to the letterbox in primates.

The entire chapter on “Learning to Read” is worth keeping in mind for its pedagogical implications in the teaching of reading. In brief, the child first has a “pictorial” stage where the visual system attempts to recognize words as though they were objects or faces; next is the grapheme-to-phoneme mapping; and last is the acquisition of “a vast lexicon of visual units of various sizes” that includes frequency information about these units and their (written) neighbors. Two pedagogical points: grapheme-to-phoneme conversion MUST be explicitly taught and emphasized (phonics), and literacy rewires almost everything in the child’s brain. Moreover, there aren’t lots of ways to learn to read: the reading brain looks pretty much the same across cultures.

What stuck with me was a strikingly brain-based description of synesthesia, and an amazing hypothesis about “normal” reader’s brains that resulted. Synesthesia is real; it occurs exclusively for learned cultural objects; and it may be due to a mutation of the genes involved in synapse pruning during development. The experimental finding was that in synesthetes, the areas activated by letters and by color patches overlap noticeably, and they don’t in non-synesthetes: the synesthete is “stuck” with his cortex in an intermediate state of specialization. The amazing hypothesis is that all children may be synesthetes: during development, as cortical specialization unfolds, there may be a period of incomplete specialization that leads to effects comparable to those in adult synesthetes!

The chapter on “Inventing Reading” outlines several features common to all writing systems, but Marc Changizi’s stands out as a quantitative and highly suggestive commonality that links our reading to the apes’ “reading of nature.” He found that the frequency distribution of certain shapes was constant, considering only their topological attributes: L and T were most common, followed by X and F, then Y and (Delta). This distribution was the same as for natural scenes! For example, a T or L shape often occurs during object occlusion, and a Y can occur at the corners of objects.

Working in apes, Tanifuji found that monkey neurons respond to a remarkably sparse representation of some object exactly as they do when the object is fully rendered–as long as certain “proto-letters” that encode “non-accidental properties” are kept in the picture. If the Y, T, X, O and J’s in an image are left, the monkeys (and humans) still recognize the object: not so if an equivalent amount is erased from the image that includes some of those proto-letters. That provides strong evidence for how we manage invariance in object recognition: we have certain neurons (or at least, monkeys do) that respond to the presence of certain shapes on the retina that probably correspond to “non-accidental” features: shapes that arose because of some object or relation between objects, not the random placing of lines.  In particular, these shapes are the ones that largely look the same when scaled, rotated, or lighted differently.

Lastly, Tanaka found some neurons that code for a black dot on a white background–posited to be an “eye detector,” which is essential for a social species–and there are other detectors corresponding to biologically useful features: but most correspond to simple geometric shapes.

Taken all together, we have here in Dehaene’s book material useful for all teachers, for neuroscientists, but also for linguists, anthropologists and scholars of the history and development of the English language. Exciting! Most importantly, we have an excellent model of how to do “soft” science rigorously and honestly, working on hot areas like culture without puffing up your claims. And a critical call to educators to experiment in the classroom: “Every teacher bears the burden of experimenting carefully and rigorously to identify the appropriate stimulation strategies that will provide students’ brains with an optimal daily enrichment.” (233)

There’s a point beyond which Dehaene goes into speculation: but it’s fascinating and appropriately qualified, so I went with him there, to some startling findings. One on symmetry: at the neuronal level, there’s a right-left brain symmetry, so that every neuron in the left region of the visual cortex  goes through the corpus callosum and maps to another neuron in the right cortex. Before processing into the letterbox region, visual stimuli presented to one half of the visual field activate BOTH neurons in the pair: initial processing is symmetric. This lends credence to the claim that initial processing is focused on object identification, where spatial orientation (and in particular mirror reversals) and motion are less important. Only later, and only in the expert reader’s brain when viewing words in the reader’s language, is a “symmetry-breaking” observed, where only the left letterbox region responds.

There seem to be TWO visual pathways that are quite distinct operating in the visual cortex: the ventral one that is concerned with object recognition and exhibits symmetric brain activation, and the dorsal one that is concerned with motion and spatial orientation, and does not exhibit this symmetry. Here’s where the symmetry can be broken: and it’s aided by motor learning (since that’s the provenance of the dorsal cortical system attuned to motion in the environment), hence the effectiveness of children tracing sandpaper letters to aid their reading acquisition in the Montessori method. Neat!

Dehaene calls for a “neuro-anthropology” that he realizes is beyond our reach, but that he believes to be a viable research orientation and program. How might we look at cultures neuroscientifically? Structural anthropologists a la Levi-Strauss already do it to an extent, positing the existence of a kind of “deep grammar” of culture that gives rise, unconsciously, to universal cultural forms, among them religion, mathematics, music and arts, facial expressions, games, legal systems, etc. Dan Sperber frames it as, “the image that emerges from the cumulated ethnographic record is not at all one of indefinite variability, but rather one of extremely elaborate variations within a seemingly arbitrary restricted set.” There’s more scientific evidence (vs. anthropological) than you might think: consider the research of Paul Ekman, who painstakingly developed a system that can encode all facial “micro-expressions,” and demonstrated that people across cultures assign the same meanings to most of these facial expressions. In music, we see that infants across cultures are sensitive to octaves and fifths, though other intervals and scales vary.

Sperber and Ekman’s data, though, leads them to posit too much constraint on culture, in Dehaene’s view. Sperber thinks of the brain in terms of different modules that developed for certain evolutionarily helpful reasons and then can be stretched a little to apply in somewhat different domains: universal structures that allow a “fringe” of cultural variability. Dehaene thinks there’s more variation possible: art forms aren’t just a “super-stimulus” that work at the limits of cortical stimulation within each of these regions, but they arise out of associations between a wide selection of mental representations that elicit complex emotions. To the extent that there are cortical modules that artists exploit, those modules have nebulous boundaries, and education and cultural acquisition can rewire their connections and boundaries substantially (perhaps the best argument for early, intensive arts education I’ve ever heard).

Moreover, like Changeux thinks, masterpieces come from novel stimulation of many regions–but not just that novel stimulation: the interactions between those regions, and their synchronous and “harmonious” (reinforcing) activation, are key. So too are amplifications of reality: as Ramachandran puts it, in a way many aesthetic theorists would like, “the purpose of art…is not merely to depict or represent reality…but to enhance, transcend, or indeed even to distort it…to amplify it in order to more powerfully activate the same neural mechanisms that would be activated by the original object.” (310) These connections are uniquely amplified in the human brain, which developed neuronal connections between distant cortical areas in the course of tool learning, has an abnormally large frontal cortex that can synthesize novel ideas and associations like metaphors, and is remarkably sensitive–even in infancy–to the communicative intentions of others.  I think there’s an interesting parallel to common descriptions of modernism here: art arising out of representing common forms in the most novel, non-traditional ways possible, art taken to the extremes of what has gone before along each possible dimension we can use to describe artistic forms.

Granted–as Dehane grants it–we’re a long way from any rigorous neuroscientific theory of aesthetics or complex cultural productions. But it’s fun and enlightening to speculate, and in the meantime, Dehaene gives us a core of very rigorous explication and a case study in how to exhibit a brain- and mind-based theory of a complex learned phenomenon without excluding its historical, social and cultural context.

As a final note in that vein–the New York Times review of this book criticized Dehaene for seeming to disagree with himself: at the same time saying that the mind is tightly constrained in its learning by the brain’s structure, and that it is remarkably plastic. I don’t think these things need to be in opposition. For one, Dehaene makes it clear that he’s positing constraints partly as a corrective to the “default social science model” of cultural acquisition via general learning mechanisms starting from a blank slate. More substantially, though, evo-devo and several other scientific developments have clearly shown us how tight constraints can produce enormous variety of mechanism and ultimate form. This is a sophisticated account of reading in culture that carefully avoids both reductionism and relativism, while incorporating both biology and historical and cultural context.