Visuality can be defined as a way of seeing shaped in interaction with items of visual and material culture. Its neural correlate or neural identity, if any, can be called “neurovisuality”—the neural circuitry laid down in populations of people using just those artifacts visually in the ways in which they were culturally intended. The paper explores why a model of the recursions of neurovisuality in natural vision might be needed in various domains of vision science and identifies particular recursions of neurovisuality that have been suggested in art-historical scholarship. The hypothesis of neurovisuality may allow a general theory of visual culture to be coordinated with a general science of vision. Possibly it can help make sense of unresolved problems in art history, including the question of the “power of images” and their “agency” in human perception. But empirical evidence for neurovisuality in the past will be hard to find. In this regard experimental investigations and historical inquiries need to join forces, and may find that the contemporary new media provide an ideal object of study.

By “visuality,” art historians mean socially constructed ways of seeing, Sehformen as Heinrich Wölfflin called them, often shaped in interaction with styles of art, depiction, and built form (often called “visual culture”).1 To take Wölfflin’s most famous example, we might compare what he called the “linear” mode of seeing exemplified by Lorenzo di Credi’s Venus (c. 1490), with the “painterly” mode exemplified by Gerard Ter Borch’s Concert (c. 1657). Both modes of seeing are also modes of painting, perhaps primarily modes of painting—a point to which I will return. In A General Theory of Visual Culture, I have argued that an interaction between vision and the visible features of visual culture—notably the recursion of “pictoriality” in vision and as vision—constitutes visuality. I also noted, however, that the recursions of this interaction are not well understood analytically, let alone neuropsychologically, as operations of retinal proprioception and subsequent processing in the visual cortex. In A General Theory of Visual Culture I ventured no speculations, then, about the neural manifestation of visuality, if any. My proposals were meant to be compatible with any neuroanatomical or neuropsychological model of imaging and visual knowing, especially with models that assume the plasticity and the pluripotency of the visual brain. In this essay, however, I push further. Should a general theory of visual culture be accommodated to a general science of vision, and vice versa? If so, how should the equation be stated?2

I. Vision, Visuality, and Visual Culture

Wölfflin understood Sehformen to be cultural styles particular to a time and place (such as the fifteenth and sixteenth centuries in western Europe in the case of Lorenzo di Credi and Gerard Ter Borch) and natural routes or relays of vision, that is, ways in which human beings are visually sensitive to contour, shape, and so on. The ways, in fact, in which all human beings are visually sensitive: in removing the background in Dürer’s engraving of Knight, Death, and the Devil of 1513 (the figures of Death and the Devil, the Knight’s dog, and the landscape) to expose the outline silhouette of the Knight, to visibilize it, Wölfflin meant to show how his readers—that is, people today—can still see the primary rhythmic configuration of a pictorial artwork made five hundred years ago. Wölfflin’s contemporaries appreciated that this investigation of expressive form in art was compatible with psychophysiological investigations of the human awareness of “rhythm” and other aesthetic orders in artworks and many other visible things. But other art historians have not fully followed him in that direction. Responding directly to Wölfflin’s treatment of Dürer’s engraving, Erwin Panofsky argued that we must understand the artist’s explicit theories of beauty and proportions (the subject of Panofsky’s earliest art-historical researches in writing his doctoral thesis) in order to interpret the allegory, that is, the Protestant (specifically Lutheran) visuality within which Dürer conceived the image—what Panofsky called “iconology.”3

Later “social historians” of art have proposed that the visual skills needed to interpret pictures are coordinated as a “period eye,” to use Michael Baxandall’s version of E. H. Gombrich’s general ethological theory (based on evolutionary psychology) of “perceptual readiness” or “mental set.” Such socially constituted visuality might be found, for example, in a fifteenth-century Florentine merchant’s ability to judge the size, volume, weight, and mass of things in space (and therefore value and cost—especially value and cost), a visual skill cultivated specifically in his tasks and purposes in commerce or banking and brought by him to the work of making sense of simulations of volume-shape produced in painter’s perspective at the time. To my mind, Baxandall may have erred in restricting explanation of Sehformen to “social history,” reducing the general ethology of perceptual readiness as conceived by Gombrich (his teacher) to a sociology of perceptual readiness that might be too limited. Regardless, the point here is that Baxandall’s notion of “period eye” has been widely accepted as a material explication of Wölfflin’s Sehformen—as “the social history of pictorial style.”4

II. The Hypothesis of Neurovisuality

In sum, visuality as conceived from Wölfflin (or before) to Baxandall (and beyond) seems to involve historical variations and specializations—variations and specializations that might be described by terms like Sehformen or “period eye.” As I would like to put it, human beings succeed to visuality when they recognize the forms of likeness that things have in a particular historical form of life—the visible and invisible aspects that things come to have in a network of analogies constituted in that form of life. Nonetheless, vision does not always and wholly succeed to visuality. Things remain visible to people outside the visuality within which they were intentionally produced, though what is visible in an artifact in this context (or what is visible about it) may differ from what is visible in the context of visuality. By the same token, people can succeed to many visualities, though both Wölfflin and Panofsky were somewhat uncertain (on different grounds) about just how far it is possible to do so when we are dealing with visualities constituted in the past and accessible to us only in things made to be visible within them that happen to have survived into our own visual world.

It is precisely for these reasons that the relations and recursions—logical, neurological, psychological, or sociological—between vision and visuality are not easy to state. I do not share Dürer’s Protestant faith, let alone his familiarity with figurations analogous to his depiction of a Christian Knight on a dread journey in the wilderness of temptation and imminent death (at least according to Panofsky’s interpretation of the iconography of Dürer’s engraving of 1513). But I can see the rhythm and balance of his engraving of the Knight, or more exactly I can see it when I am confronted with the visual replication of it in Wölfflin’s illustration, where it has been visibilized for my seeing of rhythm and balance in the engraving. (The illustration functions, then, as an autonomous artwork, though one produced by Wölfflin rather than Dürer.)

The visibility of rhythm and balance in the engraving, if any, is presumably a matter of processing in the visual brain—a material question in visual neuropsychology. Of course, Wölfflin could not invoke the results of later twentieth-century neuroscience. But he assimilated the psychophysiology of his own day, and during his own lifetime he could read experimental psychology that could have been pertinent for his art-historical phenomenology, notably Gestalt psychology. (For the sake of economy I set aside the way in which Gestaltists might have responded to art-historical formalist phenomenology, not to speak of the incorporation of both art-historical formalism and Gestalt psychology in the modern arts addressed both by art history and by psychology.) At the time other art historians made explicit use of psychophysiological concepts.5

But what about visuality? Should we suppose that historical periods or phases of human picture-making—Sehformen or “period eyes”—depend on neural circuitries unique to the human populations that used those pictures visually or, to use my terms, visually understood their forms of likeness in a form of life? (In Panofsky’s iconology, remember, we can only use a picture that was made in the distant past or in a different culture in discursive ways; we cannot fully use it visually in the way that its makers did.)

To designate the neural manifestation of the succession to visuality (if any) in natural vision, I will use the term “neurovisuality”: the neural specificity, if any, of vision-in-visual-culture, or visuality. The neologism is a convenient way to designate (hypothetical) successions to visuality in neural circuits that are laid down for such recursions in natural history and by such recursions in social life. They are laid down, then, as visual culture and in visual culture. (Still, if visual culture is nothing but neurovisuality then it may not be necessary to ontologize it: it might suffice to describe natural-historical recursions of vision in human society.) The term echoes (and in certain circumstances it overlaps) two other terms: “neuroaesthetics” and “neuroarthistory.” But it is not quite the same concept, as we will see.

The hypothesis of neurovisuality—that there might be a neural correlate or even causation to the visual succession to visuality—is unpopular among art historians, if it is entertained at all. Still, if it is correct it makes a powerful (and in some arenas a decisive) contribution to vision science from ophthalmology or psychiatry to lighting design or the engineering of human-computer interfaces (HCI)—a specifically art-historical contribution. For this reason it can be unpopular in vision science too.

III. The Hypothesis of Neurovisuality in Vision Science and Art History

To investigate neurovisuality in my sense, experimental neuropsychology must join forces with art history (and vice versa) in full measure. Why? And how?

On the one hand, laboratory or clinical experiments on visual processing in living human subjects must address visual brains that are already acculturated in historical visualities (that is, “visual culture”). But it may be difficult to detect this parameter experimentally without historical perspectives. And by definition these cannot readily be built in to any laboratory or clinical experiment.

It will not do simply to administer questionnaires and tests to populations of undergraduates in psychology courses in American colleges. In fact, it probably will not do simply to administer questionnaires and tests to any range of human populations of any kind anywhere on earth today. If art history and the historical study of visual culture are correct—correct, that is, as an account of the history of art and visual culture whether or not explicated as neurovisuality—then all living human populations possess visuality. But in theory not all neurologically possible visualities are represented in any range of living human populations on earth today. Therefore it is logically impossible fully to specify the neural correlates (if any) of visuality specifically as a question of the neuropsychological capacities and adaptations of the visual brain by way of any experiment on living human subjects. More exactly, neuropsychological experiments with living human subjects can identify a (neuro)visuality—namely, the (neuro)visuality of the subject(s) who have been observed experimentally. But this might be no more helpful than the art-historical or anthropological evidence it purports to explain. Indeed, art-historical or anthropological evidence may suggest that populations in the past or in other cultures have (had) neurovisualities different from the ones observed.

On the other hand, however, art history must be just as unsatisfyingly partial as experimental neuropsychology, though for inverse reasons. Art historians writing in the main lines of formalism and historicism from Wölfflin (and before) to Baxandall (and beyond) have usually addressed human beings in visuality without any direct experimental access to the experience of many of the people they purport to survey, and whose configurations and figurations they claim to interpret, even if such access is available. Since its consolidation in the late eighteenth century, to be sure, professional art history has had many opportunities for such experiment, notably among living human populations who have made and used the visual arts. But usually it has eschewed laboratory or clinical evidence about these experiences unless there has been a special art-historical reason—usually a biographical reason—to investigate them (for example, in the case of artists who have suffered damage to the visual brain). And it has disdained psychological and sociological questionnaires and tests as well as protocols in the pedagogy of art even when they could be salient. (Since the late nineteenth century, then, art history has rarely included in its professional purview such writers on configuration in the visual arts as Guido Hauck, Denman Ross, Hans Prinzhorn, Henry Schaefer-Simmern, Erle Loran, Rudolf Arnheim, Roy Schafer, Rhoda Kellogg, Margaret Hagen, or John Willats, regardless of their influence in institutions of art making in modern society—in classrooms, lawcourts, hospitals, and so on—and even when they have made valid contributions to the resolution of specifically art-historical problems.6)

For this very reason, art historians can overlook neural causalities that might operate outside visuality—causalities that might explain why pictures or artworks can retain their visual “power” or “agency” (aesthetic or otherwise) far beyond their original contexts of making in a particular historical visuality, that is, why they can be globally transmitted between historical visualities despite tenuous material connection between the social groups or visual cultures in question. In this regard it is not surprising that neuropsychological research has been most visible in art history specifically in the frame of “world art studies,” within which it subsists (a bit uneasily) with comparative anthropologies of art and histories of intercultural interaction in visual culture.7

At the same time, art historians may have missed a chance to enrich their historical understanding of visuality (Sehformen or “period eye”) by entertaining the hypothesis of neurovisuality. Often they have eschewed responsibility for investigating ontogenetic succession into visuality—neurological, psychological, or sociological. They have left that question to developmental psychology, projective testing, the pedagogy of art, art therapy, and other professions, where the thesis of neurovisuality sometimes has been stated too strongly or simply taken for granted.8 For example, children’s drawing, depiction, or art-making has typically interested art historians only when artists or visual cultures of the past have been interested in it, despite the obvious sense in which the very notion of Sehformen or “period eye” demands anthropological or experimental study of visual acculturation in history, that is, in the experience of human subjects being integrated over time into visualities. If children learning to draw or to interpret pictures are not instances of this historical process of succession-to-visuality, it is very hard to know what possibly could be an example of it.

In sum, neither neuropsychology nor art history is especially well placed (or has taken itself to be well placed) to address the hypothesis of neurovisuality, whether the reasons are theoretical, methodological, or ideological (most likely a mixture). Overall, vision science has approached visuality, if it has done so at all, by way of vision. Art history has approached vision, if it has, by way of visuality. But I have already noted that vision and visuality do not fully intersect, despite their essential recursion in ordinary human visual experience in history; what is visible is partly specific to each domain. Therefore we cannot predict which direction to follow analytically. From vision to visuality? From visuality to vision? Or both together, as I suggest?

In the remainder, I proceed on two levels. On one level, I will draw on research in three areas of vision science (physiological neuroaesthetics, computational psychology, and evolutionary aesthetics) in order to point out where neurovisuality might be active as a recursion in neural circuitry (with emphasis on the “might”). This is analytic: an attempt to get as clear as possible about concepts and arguments. On the other level, I will mention possible neurovisualities that have been suggested in the historical record of human art (namely, in artistic modernism, in making virtual coordinate space, and in adjustments to the vertical in built form). This is provisional and speculative.

IV. Neurovisuality and Physiological Neuroaesthetics

Though it has been defined in many ways, in general “neuroaesthetics” studies the neural correlates (if any) of aesthetic experience, and perhaps the identity of certain aesthetic experiences and certain material states of the visual brain. For my purposes in this essay, its most appealing general thesis has been well stated by the neurophysiologist Semir Zeki in his Inner Vision, published in 1999.9

The thesis has two parts. One part says that human visual imaging, or seeing, is intrinsically aesthetic: it actively configures the visual image (including any pictures presented to natural vision), like a painter painting a picture. (Zeki deploys this metaphor for all it is worth, and we might want to take it quite literally in a theory of neurovisuality—a theory of how the history of art, such as the history of painting as an art, may be “wired into” the visual brain.) Seeing, we might say, has “image structure” (to appropriate John Kulvicki’s term) in the way that the painting might have “formal structure.”10 To quote Zeki: “the brain . . . is no mere passive chronicler of the external physical reality but an active participant in generating the visual image, according to its own rules and programs. This is the very role that artists have attributed to art, and the role that some philosophers have wished that painting could have.”11

This is a familiar psychological claim (or at least the first sentence is). It is even a philosophical claim, recently reexamined by philosophers such as Alva Noë and Dominic McIver Lopes.12 Its genealogy might (or can) include Kant’s doctrine of the transcendental imagination, Ernst Cassirer’s phenomenology of knowledge, and Nelson Goodman’s constructivist psychology. (Indeed, Goodman’s Structure of Appearance and Languages of Art provide powerful analytical resources for mapping “formal structure” onto “image structure” and vice versa.) Art historians do not usually endorse it explicitly. But they are often comfortable with it: as Zeki says, it attributes processes and functions to the human brain that are often attributed to artworks or pictorial representations (and possibly have been caused by imaging these artifacts). Indeed, this part of the thesis may simply be one way of stating the thesis of visuality—that human visual perception or seeing has active modes and forms, phases and styles—without building in any particular causal explanation, that is, without appealing, say, to visual skilling in carrying out social tasks and fulfilling social purposes (as in Baxandall’s “social history of pictorial style”) or alternately to habituation in environments of visual affordance (as in the “neuroarthistory” mentioned in a later section of this essay).

The other part of the thesis derives specifically from neurophysiology. Active visual-aesthetic configuration of the visible world has its own “rules and programs” in the brain, as Zeki puts it, whether we refer to electrochemical activity in the brain that materially accompanies our experience of a painting as an art or refer to activity that produces it in the sense that if we were to stimulate or simulate the activity in the brain—let’s say by giving the subject an “art pill” or an “art injection”—we would induce just that aesthetic experience of just that painting. Soon enough, artists will begin to administer art pills, if they do not already do so, and the neurophysiological claim in aesthetics will have come full circle. For according to the strongest version of neuroaesthetics any artwork simply is an art pill or an art injection. Why?

First, there is evidence for the cortical localization and functional specialization of neural-aesthetic activity, notably the “firing” (or heightened electrical activity) of specific cell-complexes in relation to stimuli to which they are specifically adapted or for which they are “selective.” For example, in primate vision some neurons only fire when stimulated by light within certain wavelengths—the red range, say. One can also identify cells that fire in response to a vertical bar moving only from left to right in the visual field. Unresponsive to movement in the other direction, the cells can be said to be “directionally selective.”13 There are many similar findings. Hundreds of technical publications in primate neurophysiology and neuropsychology report them in detail.

For my purposes in evaluating the general thesis of neuroaesthetics, it should be possible to integrate these results—many dozens of them, many overlapped or intersecting—to give a full account of the neural identity of a given artwork or other item of visual culture, that is, of its subjective visual-aesthetic effect, of its “look” or “feel” and its “power” or “agency.” If that subjective visual-aesthetic effect includes the beholder’s awareness of aspects of the painting constituted in visuality—awareness of forms of likeness of the artifact that visibilize it in a particular way in a historical form of life—then the neuroaesthetics is de facto a neuroaesthetics of neurovisuality though it need not be strictly limited to it. (As an example of visibilizing forms of likeness, I have discussed the visibility of a building built to have a “color scheme” in a certain historical form of life, that is, in visuality. Outside the visuality, the colors of the building may be visible, but the “scheme” of the colors may not be. Within the visuality the visibility of the colors is specifically the visibility of the color scheme in the building.14)

At the moment, as already noted, most neuroaesthetic research does not explicitly entertain the hypothesis of neurovisuality. Indeed, it may prefer to skip over it to move directly to putatively panhuman visual aesthetics—to supposed invariants in visual processing. At the moment, then, it is not easy to say which neuroaesthetic findings, if any, speak specifically to neurovisuality, if any such exists, though cross-cultural or comparative experimental research may be useful if carefully framed in terms of the hypothesis. Still, neuroaesthetics can assert as a point of its principle or general theory that the whole of the artwork (including its analogical aspectivity in visuality if any) is intelligible to vision in virtue of neural wiring, whether or not that wiring was neurally laid down in recursive interactions with visual culture (that is, as neurovisuality). On this account, then, neuroaesthetics would fully replace the art-historical analysis of the look or the feel of the painting as an art (including its aspectivity in visuality). Or at least it would fully replace it if neuroaesthetics does encompasses neurovisuality.

It hardly needs to be said, of course, that the neuroaesthetic analysis (if fully realized) probably would not look much like current art-historical or art-critical descriptions of pictorial artworks, that is, like the present-day advanced “artwriting” that putatively attends both to the (neuro)intentional order of the artwork and to the (neuro)aesthetic responses of its beholder/critic as well as to the ambiguities and uncertainties within both of these horizons. The neuroaesthetic analysis would be a read-out of the neuroelectrical activity specifically correlate with the perception of the painting as an artwork. Of course, some neural “firing” will not be specific to the visual perception and processing of just that painting as an artwork and only that painting. But the particular hierarchy, sequence, and recursion of firings—the overall pattern of neuroelectrical activity—will be specific to just those paintings that have that particular aesthetic order, whether one or many.

It also goes without saying that at the moment most art historians as well as art critics and other artwriters probably believe that this read-out could not possibly be as informative as an extended discursive description of individual works. (In artwriting, one does routinely acknowledge that words—or at least words of discursive analysis, explanation, and interpretation—tend to fail us in dealing with images, or some images at any rate. As T. J. Clark suggests in narrating his own sustained attempt to engage a particular single painting as a work of art, it may only be “the physical, literal, dumb act of receiving the array on the retina [that] will satisfy the mind,” or perhaps, as he also suggests in the same book, the writing of a poem that in some way analogizes aspects of the painting or thoughts and feelings one might have in relation to it, direct or indirect. Still, the words proliferate: Clark’s meditation on Nicolas Poussin’s Landscape with a Man Killed by a Snake of 1648 as an aesthetic object for him—and a specifically visual one, as he repeatedly insists—is nearly two hundred and fifty pages long.15) In principle, however, the neuoraesthetic read-out and the extended discursive description can be fully translated into one another. Taken on their own terms, they are different representations of what we can see (or of what is seen by us) when apprehending the painting as an artwork. Our choice of the representation likely has as much to do with our disciplinary inheritances and professional territories as with any point of putative aesthetic principle. We can pursue them or not, or approve them or not, in light of what they allow us to do with our experience of the painting as an art, and to do about it, if anything. In some contexts we might reasonably prefer the extended discursive description (say, in describing the artwork to someone who has not seen it—one of the original and foundational roles of art criticism since the eighteenth century). In other contexts we might prefer the read-out (say, in determining whether the artwork has any causal role to play in arousing fear or stimulating aggression—one of the clinical arenas in which neurophysiological aesthetics might have a place). In practice, most art-historical description already is partly critical ekphrasis and partly read-out—an analytic report of patterns in the data, that is, the observed aesthetic effects and attributed intentional orders of artworks and other items of visual culture.16

In fact, there may be art-historically salient uses of neuroaesthetic read-outs that would not be possible on the basis of extended discursive descriptions of individual works. The read-outs might make it analytically possible, for example, to identify patterns of similarity and difference in vast series of artifacts, pictures, or artworks—patterns of similarity and difference founded in their functions and meanings—that are invisible to the naked eyes, or to our naked eyes. (This point was accepted in “structural research” [Strukturforschung] in art history and archaeology in the earlier part of the twentieth century, which pioneered typological, seriational, and statistical methods of formal analysis.17) In the theory of visuality that I have proposed to defend, two morphologically indiscernible artifacts or artworks can be distinguished analytically—and may be distinguished in seeing, in visual use—in virtue of the different forms of likeness they relay (a mere multicolored building, say, as distinct from a color-schemed building). In principle, the neuroaesthetic read-out should capture this distinction, in turn enabling us to “excavate” complex networks of forms of likeness that may be inaccessible to introspection or ethnography—not visible, that is, either to the historical actors precisely because the forms of likeness in question are the very grounds of the visibility of visual culture for them or to the art historians situated outside this visuality.

Art history is a long way away—probably decades away—from fully actualizing research of this kind. Instead, and partly for this reason, it remains deeply bound to visualist and formalist prejudices—its claim of responsibility to “what we see” in and as individual art-objects—even when many historical questions about visual culture are questions neither of visibility nor of sensuous form and cannot be answered by focusing on individual art-objects. As I would like to put it, they are questions not (or not only) of how an artwork or artifact looks but (also) questions of what it is like. Still, we can predict that some art historians in the future may pursue a post-visualist and post-formalist phenomenology (paradoxical as that might sound) by way of neuroaesthetic investigation and its potential to identify—empirically to track—the forms of likeness that constitute visuality in the replication of series of artifacts, pictures, or artworks.18

Admittedly it may be premature to judge these matters. Here we need to stick to the question of neurovisuality in neuroaesthetics. As noted, neuroaesthetics is probably only relevant to art history, and art history to neuroaesthetics, if the hypothesis of neurovisuality is correct. Where exactly does it enter the story analytically?

Overall, cells in one region of the visual brain, known as V4, activate when colored arrays are viewed, that is, when color is neurally constituted. V5 activates when the subject engages moving affordances, maybe by moving. In Zeki’s summary diagram of the confluence of color and motion processing in vision, then, a multicolored “Mondrian stimulus” of the kind introduced by Edwin H. Land engages V4, while a black-and-white televisual or digital-animated stimulus engages V5.19 To be sure, configurations made by Piet Mondrian himself involved calibrations of figure, ground, edge, and frame that were not configured in Land’s “Mondrian stimulus.”20 In turn, then, we might suspect that painters like Mondrian manipulated the routines of natural color vision (or other aesthetics of the visible) in their painting as an art, that is, in Mondrian’s case, in making his versions of the “Mondrian stimulus.” Neuroaesthetics not only makes this assumption. As noted, it tries to justify it neurophysiologically—to show how the subjective effects of artworks are produced in stimulating the “rules and programs” of the brain in ways that can be identified neurophysiologically.

Still, this raises the question of possible neurovisuality. Does Mondrian’s painting—does any artifact, artwork, or picture—prod the brain to reintegrate its circuitry? We know that reintegration can occur when the brain compensates for loss of particular functions due to damage or disease; some of the research results reported by Zeki and other neurophysiologists and neuropsychologists writing about aesthetics are partly derived from clinical-medical studies of brain damage in major stroke or other injury.21 Presumably artworks, unlike strokes, do not cause the brain to lose anything. But do they cause it to gain something? Something to be gained by way of the artwork?

One single painting by Mondrian likely cannot prod the brain to reintegrate the confluence of color and motion processing in V4 and V5. But the painting was generated, some art historians might want to say, in a historical visuality in which the configurative orchestrations of Mondrian and many other artists and other image makers (making productions in many domains of visual culture in many techniques and media) demanded the confluence of V4 and V5 in certain ways that maybe could only be stimulated by the integration relayed in just such works. The objective sensuous conditions of modernity, it has often been said, became its new subjective modern sensations as reprojected in its contemporary arts—a recursion debated by Walter Benjamin, Georg Simmel, and many others. Right or wrong, many artists and art critics and some art historians have treated certain modernisms in the arts as neurovisualities, though when their claim for the arts in question is stated this way they may disavow it.

To be sure, many critical and social historians of modernisms in modern art are sceptical of the claim. Certainly it can be treated critically as a historical formation in visual culture—an aesthetic theory—in its own right, like the correlate theories of nervous energy and transformation.22 As a positive hermeneutic assumption, it is most common (if often still latent as a material neurological claim) in aesthetics of modernism committed to strong claims for the aesthetics of modernism—for its material power to “alter perception,” as one sometimes hears, or to “affect the senses in new ways.” To quote Stephen Kern, “From around 1880 to the outbreak of World War I a series of sweeping changes in technology and culture created distinctive new modes of thinking about and experiencing time and space. Technological innovations including the telephone, wireless telegraph, x-ray, cinema, bicycle, automobile, and airplane established the material foundation for this reorientation; independent cultural developments such as the stream-of-consciousness novel, psychoanalysis, Cubism, and the theory of relativity shaped consciousness directly. The result was a transformation of the dimensions of life and thought.”23 To be fair, the proponents of the aesthetics in question usually blend a historicist approach to past ideologies of something like neurovisuality with their own unstated theories of neurovisuality. The latter may be universalist, referring to panhuman sensations constituted in or by aesthetic experience of the arts, or more specifically historicist or visual-culturalist in theoretical definition, referring to neural integrations in the experience of certain particular historical arts.24

I cannot possibly decide the empirical point, though deciding it is surely one of the outstanding projects for neurophysiology and art history. Instead I want to make a strictly analytic point. In Zeki’s illustration of the confluence of color and motion processing in vision, supposedly the beholder of the Mondrian stimulus is neurally constituting color in V4: the diagram shows part of his cortex “lighting up” at the reflected luminance of the green patch in front of him. (In Land’s experiments, and in his theory of “retinex” or the processing of retinal proprioception in the cortex, the question is the similarity or difference of that green patch, qua green, to other patches perceived to have the same or different colors.) But he is not seeing a Mondrian, as already noted. And not only because the pattern is not in Mondrian’s style or by Mondrian. Even if it were a Mondrian, the beholder depicted in Zeki’s diagram stands too close to it to see almost everything else: bounded rectangular planes of discrete but uniform colors partly occluding one another at different apparent distances from the imaging point and regardless of the real variance of luminance across the painting. If the beholder is to see those attributes of the painting (painting them in vision), that is, if he is to see a Mondrian, then he has to see the configuration integrated by Mondrian in those very actions—succeed to the colors, planes, and virtual depth configured by Mondrian to be visible to him in seeing the painting. In other words, when we look at things that have been actively configured for our seeing as actively configuring what is seen we aestheticize twice over or in a feedback loop, redoubling the aesthetic momentum of seeing: we paint the painting painted for our painting of it—repaint it. This recursion or redoubling is a necessary condition for neurovisuality even though it may not be sufficient for it.

I want, then, to supplement Zeki’s point that “the brain is an active participant in generating the visual image, according to its own rules and programs—the very role that artists have attributed to art and the role that some philosophers have wished that painting could have.” In some contexts, art (or other things made specifically to be visible to us) may be an active participant in generating the visual image, according to its own rules and programs—the very role that philosophers have attributed to the brain, and the role that some artists have wished that vision could have. In modern human lifeworlds, we are always in such contexts. Where might we look to find this recursive redoubling of actively-configuring vision by way of the actively-configured visual culture that it sees? In the next two sections I explore a possible example.

V. Neurovisuality and Visual Computation

Consider our visual inspection of a common natural thing. In his book of 1982, Vision, David Marr illustrated an early stage in the “computation” of information transmitted in reflected light to visual proprioception: a leaf on one stalk hanging in front of a leaf on another stalk, or as he put it an “image of two leaves.” Marr’s illustration models information at (or in) photoreception—what he called the “gray level” of the “image” (color has not yet been computed at this stage of visual processing). The table accompanying the simulation of the “image” at photoreception assigns numerical values to the discrete units of the image (not exactly pixels, they are discrete incidents of photoreception): the measurable “intensity value” of luminance at these locales in the image. But where in the numbers can we find the distinct edge of the leaf, or the boundary or gap between the leaves, that we can see with just a bit of work? As Marr wrote, “there is not a sufficient intensity change everywhere along the edge . . . to allow for its complete recovery from intensity values alone, yet we have no trouble perceiving the leaves correctly.”25 Marr explicated this observation in a complex model (what he called a “representational framework for vision”) of the hierarchical computation of information in reflected light sequenced into three “representational stages” beyond the early and primitive gray-level image that “represents intensity” (modeled in his illustration of the “image of two leaves”): what he designated (1) the “primal sketch,” (2) the “2½-D sketch” (a “viewer-centered coordinate frame” in which the edge is getting computed in the discontinuities in the surface and in “distance from the viewer”), and (3) the “3-D model representation” (an “object-centered coordinate frame” in which the edge gets fully computed as a spatial distance in depth).

Marr’s model is complex, and he stated it in several ways. To use his own words, “The overall framework . . . divides the derivation of shape information from images into three representational stages . . . (1) the representation of properties of the two-dimensional image, such as intensity changes and local two-dimensional geometry [i.e., primal sketch]; (2) the representation of properties of the visible surfaces in a viewer-centered coordinate system, such as surface orientation, distance from the viewer, and discontinuities in these quantities; surface reflectance; and some coarse description of the prevailing illumination [i.e., 2½-D sketch]; and (3) an object-centered representation of the three-dimensional structure and of the organization of the viewed shape, together with some description of its surface properties [i.e., 3-D model representation].” Marr took the primary theoretical problem to be the transition from (2) to (3) above. Given the information encoded in the image (by stereopsis, shading, texture, contours, or visual motion), the sequence of early visual computations from the image to the primal sketch and the 2½-D sketch (i.e., from image to [1] to [2] above) is “unsuitable for recognition tasks” (that is, insufficient in identifying what the shape is the shape of) because it depends critically on the vantage point. As Marr put it, “[i]t must be remembered that coordinates referring to the line of sight are not very useful to the viewer” precisely because “one must continually allow for the angle of the line of sight, .  . . a difficulty that is compounded by the effects of eye movements.” Therefore the crucial final step of visual computation (i.e., from [2] to [3] above) likely “consists of transforming the viewer-centered surface description into a representation of the three-dimensional shape and spatial arrangement of an object that does not depend upon the direction from which the object is being viewed.” Seeing, we might say, is always subject to the visual angle; it is always coordinated in natural visual perspective. Nonetheless it extracts a recognition of an object by computing a representation away from the vantage point or as it were around it. Momentarily we will see why this theoretical problem (perhaps an artifact of Marr’s own theoretical conceptualizations) might have a historical solution.26

Most important, we see the edge or gap between the two leaves more or less easily, Marr thought, because of what he called “consistency-maintaining processes in the 2½-D sketch.”27 Still, we can see the edge in several ways. (The image in Marr’s sense is ambiguous.) I may see the leaf on the lefthand side of the image as “behind” the leaf or leaves on the righthand side of the image in virtue of the apparent continuity of its contour with the stretch of leaf to the right of the middle stretch of leaf—one of Marr’s “consistency-maintaining processes.” I see lefthand and righthand stretches of leaf, then, as the same leaf—recognizing the leaf behind the middle leaf. At the bottom of the leaf in “back,” this continuity seems readily computable; the curve connecting them is smooth. At the top, however, no smooth continuity can be constituted. Moreover, there is a stark contrast in intensity values along both connecting curves (“bottom” and “top” in the image), smooth or not. Given this, we might compute the leftmost stretch of leaf as a third leaf arising from a stalk that is not visible—a leaf abutting the middle leaf, lying in the same plane across the line of sight. The boundary or “discontinuity in the surface” (supposedly seen as the one edge of the leaf “in front,” silhouetted as contour against the leaf “in back”) is where these leaves are touching along both their edges—not separated by the distance from the vantage point that can be computed at any point on the edge as a quantity on the Z-axis. (The image is two-dimensional; it encodes information on the X and Y axes of the plane in a viewer-centered coordinate frame. As yet there is no Z-axis plane—no “third dimension”—coordinate with the X and Y axes.)

Whether there really is a third leaf can probably be resolved by moving around the objects in real space. (I say “probably” because it might be theoretically possible to design objects in real space that always remain ambiguous about their spatial relations in three dimensions at any and all possible visual vantage points, even if the ambiguity changes its visual particulars from vantage point to vantage point, each having its own ambiguity—and even if succeeding ambiguities partly resolve preceding ones.) But assuming no motion of the vantage point, in Marr’s model the viewer-centered representation of the image feeds into the object-centered one, and helps constitute. And that representation could have two three-dimensional renditions computed from the intensity values of the image. One is objectively correct and the other is incorrect. To get us to the one and not the other, visual processing according to Marr prefers to integrate the intensity contrasts and primal (dis)continuities represented in the 2½-D sketch in order to give “rough depth” and “distance from the viewer”—thus two leaves, not three. This is the very idea of Marr’s two-and-a-half-dimensional representation. And a strange animal it is: for some critics, too strange quite literally by half, an internally contradictory sleight-of-hand in Marr’s model of three-dimensional visualization.28

But in a recursion in neurovisuality, the 2½-D representation in visual computation might be perfectly viable. As commentators on Marr’s model of the representational framework of vision have pointed out, it is a widely-used technology of orthographic projection, usually designated as axonometric projection in “paraline drawing.”29 Equally important, it is a common way in which two-dimensional renderings on the plane three-dimensionalize when the visual angle at vantage point constructs what David Summers has called a “virtual coordinate plane,” that is, a Z-axis-plane visibly coordinate with the plane of the X and Y axes—the “plane of the format” in Summers’s account (equivalent to the “picture plane” if the picture in question is constructed in linear perspective) and the plane of the “image” in Marr’s model.30 If this rule and program of depiction loops into the rules and programs of vision, then Marr’s problem could take care of itself in the modern human case—that is, in a neurovisuality. The Z-axis-plane would seem to be rarely if ever encountered as a visible plane in nature outside pictures. (Where, for example, is the flat “floor” in the arboreal space of the forest in which the leaves will likely be seen in natural primate vision?) It only becomes fully visible in virtual pictorial spaces. Hypothetically, once the brain computes visually (or in Marr’s terms once it represents the image) by way of this plane, if it does, it can spatialize intensity contrasts, surface (dis)continuities, and so on, in terms of “rough depth” and “distance from the viewer,” just as Marr requires of the 2½-D sketch as one of the sequential representations of the gray-level image in visual processing.

Indeed, it might be possible to eliminate this mysterious stage in the overall representational framework, that is, to move directly from primal sketch to 3-D model representation. After all, the main theoretical job of the 2½-D sketch as Marr conceived it is to take the representation of the image from a viewer-centered coordinate frame (insufficient for object-recognition) to an object-centered coordinate frame (in which the shape is readily recognizable as the shape of a particular object-volume). But this can be done on the virtual coordinate plane when it is visibly coordinate at right angles with the upright plane of the format or the picture—something visible only in artificial architectural spaces architectonically configured to have just such a coordination. For this coordination sets up a what might be called a “box” or “quadration” that situates things virtually in the three-dimensional coordinate space they inhabit; regardless of visual angle (that is, of viewer-centered coordinates), we can see the relation between the depicted object and the coordinate frame, that is, the intersection of the plane of the format (or the picture plane in linear-perspective constructions) and the virtual coordinate plane (depicted or not as an optical plane in the picture). We can see the object, in other words, in what might be called “virtual coordinate space.” When fully generalized or extended to its “notional abstraction,” this virtual space might be called “metaoptical,” to use Summers’s terms, because the virtual coordinate space visibilized in pictorial architectonics becomes notionally identical with infinite homogeneous three-dimensional coordinate space (or Cartesian point space).31 But any virtual coordinate space can be sufficient to three-dimensionalize a depicted object in natural visual perspective—that is, in natural visual perspectives on pictures in architectonics in which a virtual coordinate plane appears. In a recursion of neurovisuality, it might be that natural visual perspective enfolds this pictorial effect in its representations—its sequential and hierarchical recomputations—of the primordial image.

VI. Neurovisuality and Evolutionary-Ecological Aesthetics

The history of this recursion, if it has occurred, requires further analysis. The philosopher Marx Wartofsky urged the radical thesis that the “dimensionality of visual space” in visual perception (human abilities to apprehend and interpret ambient space as three-dimensonally coordinate and possibly as infinitely extended in a correlate metaoptical coordinate space) was a consequence of the “pictorialization of visual space” acquired through “practices and conventions of pictorial representation” that had been developed in Classical Greek and Renaissance Italian styles of depiction, notably the invention of linear perspective projections.32 This proposal would seem to follow from Wartofksy’s more general historicist thesis that “modes of our visual cognition change with changes in the modes of our pictorial representations” and specifically that “canonical styles of representing the seen world change . . . and introduce transformations of vision.”33 Wartofsky himself did not invoke the biohistoricist hypothesis of neurovisuality in my sense because he wanted to say that human vision has a history that “goes beyond the biological evolution of the hominid visual system and is part of that activity of self-creation and self-transformation which we call cultural evolution.”34 But if we set aside this reification of cultural evolution, Wartofsky’s thesis is compatible with the hypothesis of neurovisuality, and in the end it may require it. What Wartofsky calls “self-creation and self-transformation” simply is part of the biological evolution of primate vision once any feedbacks were introduced into it by cultural activity—by using sticks, stones, teeth, and bones to do and to make things and especially to depict things. (This brute culture still needs to succeed to what I have called “culturality”—awareness of the forms of likeness of artifacts produced in cultural activity—in order for it to constitute a visuality in my sense. Brute or “osteodontokeratic” culture can be found among monkeys and great apes and it is bioculturally characteristic of hominid species in the human line. But the visuality of culture—and disjunct visual cultures—may be a more recent development in Homo.35)

Restated as a historical identification of a supposed neurovisuality constituted in interaction with painter’s perspective, Wartofsky’s “dimensionality of visual space” may still seem untenable. As Arthur Danto has complained, there can hardly have been substantial neural evolution “in the bare six hundred years from Giotto to Ingres,” or at least any evolution of the scope that Wartofsky’s thesis would seem to entail.36 For all art-historical intents and purposes, Danto would treat human vision as invariant since the Upper Paleolithic period. Indeed, he has argued that art historians categorically depend on treating vision as an invariant, for otherwise their identifications of pictorial styles (even as “ways of seeing” or “period eyes”) cannot be possible in the first place.37 Still, we should reserve judgment about the pace of biocultural evolution and therefore about the rate at which any recursions of neurovisuality could be disseminated.

In this regard, Wartofsky’s art-historical chronology might be way off even if his historicism can (perhaps must) be accommodated to evolutionary histories. Painter’s perspective in the Italian Renaissance was not the first place, or even the most important place, in which the “[three-]dimensionality of visual space” could be constituted pictorially. When visibilized, the virtual coordinate plane naturally three-dimensionalizes and spatializes depicted objects—“perspectives” them—without using the particular techniques of painter’s perspective. As Summers has argued, it can be found in ancient Egyptian pictures made at the beginning of the third millennium BCE. In fact, he has suggested that it was metrically organized in Egyptian pictorializations—that the plane was segmented in bands of equal width on the plane or of “depth” in the resulting virtual coordinate space. As he writes, “Egyptian painters and sculptors made choices that were to establish the basis of Western metric naturalism . . . by the development of planarity into the virtual dimension [i.e., the virtual coordinate plane], with consequences reaching to the present day.” Summers treats the history of these long-term consequences as an art history—a history of successive styles and technologies of pictorial representation building on the visibilization of the virtual coordinate plane in Egyptian pictoriality, culminating in painter’s perspective in the Italian Renaissance before its metaoptical generalization in Cartesian point space.38 Still, Summers does not always undertake to show how the technology was transferred from one locale of visuality to the next—for example, from ancient Egypt to archaic Greece—despite an extensive discussion of the conceptual origins of painter’s perspective in Arabic optics. I do not think that he would endorse the hypothesis of neurovisuality as I have tried to state it; his world art history depends on a strictly psychological (and Kantian) conception of the contribution of understanding (or the transcendental logic) to sensibility and its intuition of the sensible manifold (transcendental aesthetic) in a kind of transcendental deduction, or what he calls “abstraction to the notional.” But the hypothesis of neurovisuality could help enable him to explain how the consolidation of the virtual coordinate plane was disseminated, ramified, and preserved in human visualities and pictorialities, some of which had little material intercultural interaction.

In this regard, the virtual space constructed in painter’s perspective is a particular historical variant of spatiality constructed on the virtual coordinate plane; as Summers puts it neatly, “the orthogonals in a perspective construction are ‘really’ parallel lines perpendicular to the baseline, and all modules marked off by transversals in the grid are ‘really’ perpendicular to them.”39 These parallel lines can be constructed on the virtual coordinate plane, whether or not they are treated as modules. The ancient Egyptian examples given by Summers may be questionable. But it seems likely that some Greek architectural sculpture (such as the frieze of the Parthenon at Athens) was organized by explicitly planning the spatial relationships of depicted objects and figures on the virtual coordinate plane before laying them out as pictures on the plane of the format and carving them back to the secondary plane(s), even if these plans did not have to divide the virtual coordinate plane into bands of equal width in which the figures were located and even if the figures were not reduced in size on the plane of the format proportionate to their location in depth (as in perspective projection).40

Indeed, the virtual coordinate plane could well be found in any visual culture in which pictures are installed on flat upright surfaces axially organized as perpendicular to the line of sight (though permitting the oblique axis that naturally visibilizes the plane under certain visual angles allowed or enabled by the architectonics). It could be found, that is to say, in virtually every large-scale or monumental architecture known to us in complex societies, in which planed planks of wood, dressed blocks of stone, and other flat, rigid materials have been used to construct what has been called a “carpentered” visual world of right-angled architectures or “cuboid” architectonic spaces into which the virtual spaces of pictures were integrated. Often associated specifically with the rise of state-level civilizations in the ancient Near East, the Nile Valley, and elsewhere, this monumental architecture and the pictorial architectonics correlated with it is both very ancient (Neolithic) and practically worldwide in distribution. Many different kinds of visual and virtual spaces and many different kinds of pictorial effects can be constructed within it. But all of them can dimensionalize visual space in the correlate pictorial architectonics; within well-defined limits of the visual angle, all of them permit the visibilization of an artificial or man-made visual plane coordinate with the plane of the image in a retinocentric or viewer-centered frame.

The notion of a carpentered (visual) world—of a visual world that has been carpentered—has a number of ancestors. But it achieved classic formulation in famous studies by a trio of psychologists and anthropologists, Marshall H. Segal, Donald T. Campbell, and Melville J. Herskovits, who examined cross-cultural responses to the Müller-Lyer Illusion, exploring whether perceivers sensitive to (visually sensitized in) effects of plane recession in carpentered architectural environments (such as receding walls at right angles to the groundplane and increasingly distant from the vantage point) would transfer this sensitivity or skill to spontaneous interpretation of the two-dimensional graphic stimulus.41 The thesis is usually stated as a strictly psychological hypothesis about cultural relativity in visual perception, not a thesis about a historically evolved neurovisuality that is activated in contexts of visual affordance similar to the ones in which the neural circuits were laid down. Though not mutually exclusive, these hypotheses might be related analytically in a variety of ways. Onians has emphasized that the original study depended on an overly narrow (and ideologically shaped) hypothesis—namely, that perception can be influenced by culture—rather than a “broader” one, one that he says “goes further”—namely, that perception is influenced (neurally shaped) by environment, “whether cultural or natural.”42 But the more encompassing hypothesis must perforce include the narrower one. And the latter may require a special theory of particular recursions in vision: that is, of neurovisuality.

Still, problems abound. Many statements of the thesis as tested by the perception of geometric illusions (1) construe as possible effects of a carpentered world what could equally be described as effects of a “perspectived world”; (2) overlook possible culturalized interpretations of the illusion other than the “carpentered” ones, and in general downplay what I have called “radical pictoriality”43; (3) attribute carpentered worlds as a matter of real architectures only to urban and/or Western civilizations, often modern ones; and (4) understand carpentered worlds overly literally as a matter of visual spaces in real architectures as opposed to visual-virtual spaces in man-made architectonics that might include natural vistas, landscapes, buildings, pictures, and other artifacts organized axially, or in terms of what Summers calls “paths” and “centers,” and in terms of frontality and planarity (in the case of pictures installed in such architectonics). These limitations on statements of the thesis and cross-cultural experiments designed to test it mean that its cultural reach and historical depth, let alone its neurological implications, remain uncertain. For immediate purposes, I note here that the original hypothesis did not take the virtual coordinate plane in Summers’s sense to be responsible for the interpretations of the geometric illusions preferred by urbanized subjects, even if the plane is visually constituted or pictorially constructed only in carpentered architectonics. Rather, it took the interpretations to be steered or partly caused by certain effects of perspectival recession in carpentered worlds. Though related, these visual calibrations are analytically distinct. The virtual coordinate plane in Egyptian pictorialization did not lead to perspectival treatment of depicted objects on the plane of the format—no recession and no diminunition—even if such phenomena were perfectly visible in natural visual perspective in ancient Egyptian architectures.

Before Summers, perhaps the most sustained visual-psychological discussion of the standpoints, sightlines, planes, and spaces constructed in the monumental architectures of the ancient world was attempted by the architectural theorist Sigfried Giedion. Giedion emphasized the verticals and “verticalization” constructed in the monumental dressed-stone architecture of Egypt and Sumer, which he contrasted with the “multi-orientationality” of Paleolithic cave painting and other rock arts.44 “Adjustment to the vertical” is not quite the same thing, however, as visibilization of the virtual coordinate plane, though it may be correlated insofar as the virtual coordinate plane becomes visible in a picture organized on the plane of a format perpendicular to the observer’s groundplane (notionally flat) and to his line of sight (when axialized to address the picture head-on). And anyway I would locate the virtual coordinate plane not only in monumental architectures of the ancient Near East, Egypt, and the Mediterranean world. It may visibilize in “megalithic” or large-scale post-and-lintel construction in Neolithic and Bronze-Age Europe and elsewhere. Probably it had independent visibilizations in rectangular architectonics and pictorial planarity elsewhere in the world. Despite the contributions of Giedion, Summers, and others, archaeologies of ancient visual-virtual spaces have yet to be compiled and compared in these terms.45

Here, and once again, I want to make an analytic point instead of an empirical one. The question of the virtual coordinate plane as possible neurovisuality inevitably brings us to evolutionary-ecological aesthetics: how aesthetic experience in Zeki’s sense, or seeing that actively configures what it sees, has been shaped in natural selection in natural (wild) and artificial (cultural) environments, however “second nature” for their inhabitants.46 The logical synthesis of neuroaesthetics and evolutionary-ecological aesthetics might be called “neuroarthistory.” It has been so called in an ambitious book by John Onians, published in 2007. Onians urges that the neural routines of vision, including the visual routines of making artifacts, pictures, and artworks, are evolutionary products of visual adaptation to distinct ecologies of visual affordance, such as seasonal illuminations of topography, typical local geology, and the growth or behavior of regional flora and fauna. These environments have their own histories: climatological; geomorphological; botanical and zoological; and, of course, hominid and human. To quote one of Onians’s formulations, vision (and visuality if any) can be most economically and comprehensively understood in terms of “automatic responses generated by neural networks whose configuration has become more or less permanent as the result of frequent exposure to particular features of our environment.”47

Neuroarthistory in Onians’s sense need not invoke visual adaptation to visual-cultural environments as the explanation of neural-visual rules and programs—of the “automatic responses” of the brain habituated in “frequent exposure to particular features of our environment.” Neuroarthistory does not assume neurovisuality, though it is open to finding it. In recent work on the Aurignacian painted cave of Chauvet, for example, Onians suggests that the painters configured a simulation of certain things they saw in a natural ecology to which they were long adapted. If we adopt the strongest version of his theory, they could only do so. If this is correct, it might suffice to say that cave-painting (that is, this cave painting) merely stimulated the routines of vision already habituated to the ecology it pictured. No recursion of neurovisuality has occured.48 I set aside the question whether Chauvet or any painted cave in the Upper Paleolithic period in Franco-Cantabria had any kind of “frequent exposure” to viewing in a population—exposure frequent enough to habituate vision, as Onians’s theory requires—or why the vision of those who did make and see it, however restricted their number, might have been preferred or “selected for” in the biosocial reproduction of the population if whatever could be seen in or about the painting by these special people could be seen equally well in the extra-pictorial world by anyone else in the population. In the most economical statement of Onians’s theory, those people who did see the paintings in the cave could see and use them visually as presentations of things to which their “neural networks” were already habituated or disposed, with or without pictorial mediation.

Still, the paintings in Chauvet (on Onians’s account of them) may be special cases of trompes l’oeil. Arguably pictoriality as such has little or no causal role to play in the visual perception and interpretation of such works. Indeed, one can defend the radical thesis that we should sharply distinguish “illusionistic imaging” from depiction—that trompes l’oeil are not pictures.49 On this account, a trompe l’oeil might be able to shape vision neurally if it is frequently encountered as a particular feature of a habitual environment so long as it is not a mere duplication of just those things that can be visible just as well outside its illusion (if it is, then its causal role in shaping vision is diminished or eliminated). But it would not do so as a picture visible as such. It would bring unnatural or artificial things into being in the visual world—things such as the flat groundplanes of virtual coordinate planes—simply in virtue of the illusion.

The recursions of neurovisuality, if any, do not require that they be recursions cycled though the perception of pictures specifically. Nevertheless, pictorial recursions would be dramatic instances of neurovisuality precisely because most pictures envision some aspects of a world that are not otherwise visible in the world (or about it) in any way to which the visual brain could have become environmentally habituated. And they do so as visible pictoriality. The difficulty lies in determining when neural adaptation occurs in relation to such depiction—neurovirtuality. Even more fundamentally, the difficulty lies in determining when pictoriality as such becomes visible. When in neuroarthistory does neurovisuality specifically coordinate as neurovirtuality in a pictorial ecology?

VII. Neurovisuality Now

Over the long term, it would be surprising if human vision were not adapted to virtualities generated specifically in picture-making and cognate activities (including the making of “artificial memory systems” and “compu-notations”), that is, if its circuitries were not reintegrated in having played “image games” for more than forty millennia in (and as) different visual cultures.50 For all the reasons I have noted, however, it will be hard to detect these hypothetical successions and recursions in the past. And for this very reason, my suggestions have been analytical, not empirical. As remarked at the outset, they are intended to explore whether a general theory of visual culture can or should logically be accommodated to a general science of vision.

Of course, it is one thing to suppose that the human species is partly disjunct from ancestral species—that it is a historical variation in the hominid line—partly in virtue of its species-wide neurovisuality in picture-making activities or in the production and material management of particular aesthetic sensations. Clark, a historian of modern art, has been happy to identify the “species-defining” nature of the “form” that he thinks emerged in tool-making in Solutrean cultures of the Upper Paleolithic period—presumably an order of manual, visual, and mnemic order that (he thinks) indexes speciation.51 And it is another thing altogether to suppose that in neurovisuality the human species is continuing to vary—to diversify in ways that could lead to speciation. Clark would hardly suppose, I would guess, that artistic modernism is species-defining, whatever else it defines. Modernist rhetorics of the creation of a “New Spirit” (or a “New Man” or a “New Woman”) in the regimes of modern sensation and its reintegrations and reprojections in modern visual and material cultures have rarely gone that far. If they have, the proximity of dubious eugenics—of sociogenetic engineering by means of art and architecture—is obvious. If “creative evolution” occurs at all, presumably it is not limited to the evolution of late-modern men and women.

It is striking, then, that the rhetoric of present-day new media routinely asserts their power in terms of neurovisuality: the rules and programs of the software (sometimes conceived as having a self-autonomizing epiprogrammatic capacity) are getting wired up in those of the wetware, the human brain. Maybe this is just a metaphor for addiction or other processes of habituation and acculturation that do not amount to neural reintegration, or could be said to cause it. The wetware voraciously consumes the software in part because it has produced it specifically to satisfy cravings for imaging not so readily released from human image banks by other technologies or by natural visual perspectives unmodified by man-made extensions into virtuality—virtuality expressly tailored pictorially to be stimulating, often sexually. But in other times and places, in any time and place, it might well be that the then-contemporary “new media” exerted a similar grip or had a similar efficacy—that there is nothing neurally new about the effects in question. (Certainly the extraordinary expenditure of human energy in the Paleolithic visual cultures has long been taken to betoken a “creative explosion” in human media and even in human mind—a world-historical threshold.52) New-media enthusiasts point to new forms of community and subjectivity that emerge from personal and social interaction in new media. But there does not yet seem to be any clear evidence for infraspecific variation, let alone interspecific variation, driven by new-media adaptations of neurovisuality. Is it too soon to tell? Or simply unlikely?

How can we address this contradiction? In conclusion, I notice the analytic equation with regard specifically to the vexing empirical question. The many “old media” can be investigated in many ways, from ophthalmology to art history. As we have seen, however, recursions of neurovisuality, if any, are likely to be invisible analytically, at least in part. They are a “black box”: we cannot make the relevant neuropsychological experiments; comparisons and controls are inaccessible; evidence is indirect, read out of uncooperative fossils that present many forensic difficulties and must be subject to intrusive interpretation, especially if they are pictures or artworks. In technosocial environments of the new media today, however, we would seem to have ideal scientific and hermeneutic conditions to investigate neurovisuality—for the very first time in history. For the first time, psychophysiological observations of the electrochemical activity of the human visual brain or other experimental and clinical investigations can be brought into direct relation with introspective, ethnographic, and sociological information about subjective experience in light of the historical thesis that interactions with visual-cultural media generate new neural circuitry. Which media and what effects produced in them stimulate neural reintegration and adaptation, if at all?

In our own time, this question should provoke terrifying ethical and political excitements and doubts—inevitable excitements and essential doubts. But there is no way around that. And it may be just as well. Within visuality we might accept neurovisuality, or contest it—we must do so. For if one thing is certain it is that somewhere some people are now working very hard to bring neurovisuality into being.