The term “rock art” defines non-utilitarian, humanly made markings on natural rock surfaces that appear to be symbolic. Occurring in nearly all countries, this phenomenon constitutes the major corpus of evidence we possess of humanity’s cultural, cognitive, semiotic and artistic beginnings; it is the principal component of surviving pre-historic cultural heritage. Its study is today an interdisciplinary, multi-facetted scientific pursuit, which replaces traditional archaeological approaches that focused on perceived styles and meanings.
Much of this global palaeoart patrimony is under threat, not only from natural agencies, but also and most especially through destruction by human agency. The latter can include the conduct of researchers, the effects of site tourism, industrial and other development, and polluting emissions that generate atmospheric acidification. Many methods have been developed to study aspects of rock art conservation, to learn how and when rock art was created, and to record the images on rock surfaces. In all of this work, there is a distinctive trend to preferring non-intrusive methods of study, which involve no physical contact with the rock and no removal of samples for analysis. Those applied to petroglyphs (markings made by removing material from rock surface) and pictograms (made by adding material to a rock surface) tend to differ, especially in analytical and preservation work. For instance, attempts to determine the age of the latter type, which occurs in the forms of rock paintings, drawings, prints and stencils, usually focus on the age of the applied substance (or some inclusion found in it), which in the case of petroglyphs is not recoverable.
Scientific work in this field includes the study of the tools and materials used in rock art production, and the determination of paint compositions and microscopic inclusions or other features illuminating processes and behaviour. Often the methods used in this resemble those of forensic science. Other work so far conducted has addressed the chemical sourcing of pigment materials, and the microscopic excavation of strata of paint residues, mineral accretions, weathering phenomena and patination zones. Of importance is also the secure discrimination between natural and humanly made rock markings, to ensure that neither is mistaken for the other.
The iconographic interpretation of rock art, which in the past has dominated the concerns of this field of research, can only be regarded as being scientifically based when sound ethnographic information is available. This may be oral, deriving from the artists or knowledgeable informants of the same culture, or alternatively it may derive from decipherable inscriptions accompanying rock art imagery, in specific world regions. Such access, however, does not exist in most circumstances, and other iconographic interpretations are merely freestanding constructs of autosuggestion, reflecting the interpreting intellect and perception; they are not testable.
Alternative forms of interpretation are more promising, e.g. through the use of analytical tools provided by the cognitive sciences and semiotics. Human knowledge derives from concept-building cognitive processes responding to external stimuli, thereby accumulating percepts. The introduction of consciously created sensory information stored outside the human brain in the form of symbols rendered perceived reality conceptually manageable. Conscious experience became possible because at some point in human evolution the neural facilities prompted by the production of early symbols became available for the processing of reality’s stochastic stimuli in visual and mental taxonomizing formats. Thus the very early rock art forms the major remaining precipitate of our cognitive evolution and is a potential source of information in the quest to understand it. In this, the non-figurative component of rock art may be more instructive than the figurative, which in orthodox archaeological approaches has been treated as the principal source of information.
“Rock art” defines somewhat arbitrarily non-utilitarian, humanly made markings on natural rock surfaces, made either by an additive (the application of material) or a reductive process (the removal of rock material). The former results in a pictogram or rock painting (including pigment drawing, stencil and beeswax figure); the latter is a petroglyph or engraving, sometimes called carving. The term rock art is usually not applied to human markings on prepared or dressed stone surfaces, such as may be found on buildings or rock-hewn structures (e.g. temples or pyramids). Nor does it include humanly made but unintentional rock markings (e.g. occasioned by bulldozers), utilitarian rock markings (e.g. axe grinding grooves) or marks made by non-human animal species, even if made “deliberately” (e.g. certain forms of cave bear claw marks in many European caves). Thus the term “rock art” is quite arbitrary, intended to refer to rock markings of semiotic content.
Rock art occurs in nearly all countries. Its uneven distribution is not so much attributable to differences in cultural conventions, it is primarily a taphonomic attribute (i.e. a result of preservation bias). In particular, the high-pH and low precipitation regimes of arid regions have greatly facilitated its preservation in such areas as the Sahara, Arabia, central Asia, the American Southwest, Peru and Australia. Another major determinant of rock art distribution is geology. Some of the largest surviving concentrations are those found in the sandstone facies of the former Gondwana plate, which have facilitated the formation of rock shelters that provide excellent preservation conditions. Similarly, the practice of Upper Paleolithic rock artists to place some of their productions in deep limestone caves has significantly helped the survival of some of that period’s rock art. By comparison, the survival of Pleistocene rock art at open sites is limited to very weathering-resistant rock types and primarily to arid regions.
Pre-historic rock art represents by far the largest body of evidence we possess of humanity’s cultural, cognitive and artistic beginnings. Through its relative permanence, it has profoundly influenced the beliefs and cultural conventions of subsequent societies up to the present. It is therefore an integral part of humanity’s collective memory, and the greatest surviving witness of our cultural, cognitive and semiotic evolution.
Historical and geographical overview
Until recent decades, reliable information about global rock art remained severely restricted. For instance, no publication about Chinese rock art had appeared in English until 1984, yet the earliest literary mentions of rock art are from China. The philosopher Han Fei (280–233 B.C.) provided the first known reference to rock art, while the geographer Li Daoyuan (A.D. 386–434) described numerous rock art sites in China and even mentioned occurrences in India. In South America, Captain De Carvalho first reported rock art in 1598 in what is now Brazil, and published his recordings in 1618. The first known recordings in Europe, made by Peder Alfssön in Denmark in 1627, were not published until 1784. More determined scholarly efforts commenced during the 19th century, focusing initially on Russia, Scandinavia and northern Africa, later on southern Africa, parts of South America, North America, Australia and eventually India.
With the beginning of the 20th century, after orthodox archaeology finally accepted the authenticity of Franco-Cantabrian cave art (which it had rejected for decades), the study of rock art became nominally integrated into mainstream archaeology. This promoted the proliferation of stylistic constructs and the development of ultimately unproductive methods. For instance, some archaeologists considered that taxonomic constructs and statistical analyses of stylistic or morphological matrices of motif types would provide empirical interpretations, in the same way other artifacts were classified and interpreted statistically. However, rock art has no archaeologically perceptible time depth, and most major rock art sites are cumulative assemblages deriving from different eras. Lumping these different traditions together and treating them as a “style” because they occur at the same place serves no useful purpose, and this is even before the complex issues of selective survival (taphonomy) are considered. Thus the greatest barrier to integrating rock art successfully into archaeology was the intractability of its dating. Worldwide, there have been only about twenty instances of reasonably convincing minimum dating by finding rock art under supposedly datable sediments.
The last few decades of the 20th century witnessed the emergence of rock art research organizations in many parts of the world, beginning in North America, Australia and Western Europe. In 1988 these bodies formed the International Federation of Rock Art Organizations (IFRAO), which currently has over forty affiliated member associations, covering in effect most of the world. One of their principal aims is to introduce scientific methods, grounded in such diverse disciplines as geology, semiotics or cognitive science. This trend is currently replacing interpretative endeavors with contextual studies, and concerns with meaning are giving way to epistemological rigor.
The pre-eminence of the Franco-Cantabrian cave art has in some respects overshadowed the appreciation of the many other, often much greater rock art traditions, in Europe as well as elsewhere. For instance, the extensive concentrations of petroglyphs in Fontainebleau (France), Galicia, western and southern Alps or across Scandinavia receive much less attention, because they are of the Holocene rather than the Late Pleistocene. On the other hand, the Ice Age petroglyph traditions of Australia, which may well be a hundred times greater than the corpus of European cave art of the same age, also have attracted limited interest. Asia, too, comprises several bodies of rock art that surpass numerically any European regional corpus, and some of it is much older than the oldest rock art of Europe. Most of the countries of the Middle East are rich in rock art, especially Saudi Arabia, Iran and Israel. Across central Asia, including the Tibetan Plateau, there are numerous reports of rock art, but little detailed survey work has been conducted. The rock art of Siberia and China is much better explored, with well over 10,000 sites known in the latter region. India boasts not only one of the largest concentrations of rock art in the world, the currently earliest known tradition is also found there. The countries of South-East Asia all feature rock art, as do most islands in the Pacific. The world’s largest concentration, however, appears to be that of Australia, thought to be in excess of 100,000 sites. That continent’s body probably includes the largest Ice Age component, estimated to be up to 20% of the entire corpus.
Africa, too, boasts some large rock art concentrations, beginning with the several art regions of the Sahara. In terms of its artistic finery, Saharan art is matched by few traditions, one of them being the Bushmen/San rock paintings of southern Africa. Other painting and petroglyph traditions occur also in that region, and in most other parts of Africa. Finally, the Americas are also well endowed with rock art, with major concentration in the Southwest of the United States and neighboring areas of Mexico, and in the Andean regions of South America, from western Venezuela to Patagonia. Further bodies of rock art occur in much of Central America and in various parts of Brazil.
Conservation and site management
Humanity lavishes billions of dollars annually on its art objects, art repositories and art industry. By comparison, its endeavors to look after its oldest and most valuable art treasures are miniscule. Despite its appearance of relative robustness, rock art is quite fragile, and what we see today is only the tiny surviving fraction of what was once created. Two factors need to be distinguished in the deterioration of rock art: the effects of natural processes, and the damage occasioned by human agency. The mitigation of the former is often difficult, whereas that of anthropic destruction is in most cases easily achievable. Deterioration by humanly introduced factors far outweighs natural degradation. The rock art that exists today does so because it has survived a great many natural decay processes, often surviving in a state of relative equilibrium with its ambient environment. It could persist much longer if there is no significant change in its preservation conditions, especially one introduced by human intervention. This may be as simple as the introduction of human visitation to a formerly pristine site, or as complex as the occurrence of acid rain caused by industrialization.
The principal natural agent of rock art loss is moisture, mainly in the form of rainwater, capillary moisture in porous rock, condensation in caves and shelters, freeze-and-thaw cycles, surface run-off, and secondary effects such as salt efflorescence or exfoliation. Physical weathering of rock art panels occurs as insolation (solar radiation), lightning strikes, brushfires, tectonic adjustments and kinetic damage (aeolian, gravity or water induced). Many forms of biological factors can contribute to weathering, including bacteria, fungi, lichens, algae, mosses, larger plants, insects (mud-daubing wasps, termites, bees), nesting birds and various larger animals, especially domestic and feral species. For many of these threats, protective measures have been found. Site hydrology, for instance, can be controlled by artificial silicone driplines in shelters.
One animal, however, is causing far greater rock art destruction than all other factors taken together. Of the many forms of damage occasioned by humans the perhaps most repulsive is that occasioned by researchers, be it through misguided recording activities or through their role in permitting or condoning the destruction of rock art by industrial or infrastructure development. The former has been largely eliminated in recent decades, but the latter continues unabated in much of the world. Tourists and site visitors contribute to rock art deterioration, though it has often been found necessary to sacrifice some sites to them in order to preserve many others. The locations of new sites are no longer made public, and well known pristine sites such as Chauvet, Cussac and Cosquer Caves in France are totally closed to all, except a few researchers who only enter these sites with careful precautions to prevent contamination. For instance, researchers are not allowed to walk on the floor of Chauvet Cave. In Australia, most of the country’s cave art sites are only accessible to two or three researchers.
The tasks of professional rock art conservators include graffiti removal, moisture and climate monitoring and control, and the design of site management measures. The latter differ according to local circumstances, and include such measures as the erection of fences to keep out animals, the installation of visitor boardwalks and paths, and in some regions protective grilles. In modern site management practice, the concept of “site fabric” is paramount, referring to all physical and non-physical aspects of a place, including accretionary deposits on the rock, even its ambience or religious significance. The primary principle of intervention at a rock art site is that any modifications must be fully reversible. Today’s site conservation and management practices may well be superseded tomorrow, and the cultural resource in question is, after all, not renewable.
The study of rock art
Since rock art has begun to be recorded, centuries ago, the purpose of such records has always been to create a visual register of those aspects of the art that were deemed important. This has remained so until quite recently, and it follows that rock art recordings are usually interpretations of individual observers, not objective data. Indeed, this principle is embodied in a ruling of the High Court of Austria in 2003, that rock art recordings are copyrighted because they are individual interpretations by the recorder. This is now changing with the introduction of sophisticated digital recording systems that yield much more objective results.
Nevertheless, the ready availability of computer equipment and electronic image manipulating software does not necessarily obviate other recording techniques. It is certainly appropriate to discard all those that are invasive or threaten the research integrity of rock art. Many such methods have been used extensively in the past, but there is no longer any justification to continue with them. These physical enhancement methods have included the application of clear liquids to close the pores of silica skins or other thin accretions, thus improving photographic records. Another common practice has been the outlining of rock art with chalk and a variety of other markers, including dye, pencil, lipstick, and felt pen. Archaeologists have contaminated the geochemical fabric of thousands of square meters of petroglyphs by applying organic white and black paints, to facilitate manual recording. The use of pressure-sensitive films, rubbings made with a great variety of materials, the production of casts from latex, plaster of Paris, papier mâché, thermoplastic resin and so forth have all been found to affect the rock art, and in some cases have caused spectacular damage to it. The use of transparent film to copy fragile art can also be damaging, because these sheets tend to be electrostatic and the movement of pens or fingers can attract small flakes of material from paintings. Even the use of aluminium foil tamped gently into petroglyphs before it is backed by stiffer material, regarded as a reasonably safe method, has been opposed by a chemist working with rock art.
There is one very simple rule now in recording: unless the rock art in question is about to be destroyed by other factors, no invasive method and no contact is acceptable. It would be selfish to prejudice future analytical methods rock art scientists of future centuries might bring to bear upon the rock art—methods we cannot begin to speculate about.
There is no need to resort to damaging and superseded methodology. Photography, sometimes in combination with non-contact enhancement techniques, is now universally available. Raking light photography (oblique lighting at night) is far more effective in recording petroglyphs than manual recording, which is a cumbersome and subjective procedure. A variety of filters and special films are available to improve photographs of rock art. Cross-polarized photography, using two light sources with polarizing filters, can greatly enhance contrast. It is important that a calibrated color and gray scale be included on all rock art photographs, the most widely used being the IFRAO Standard Scale. This has a number of purposes, the foremost being the facility of color reconstitution. All photographic records are of distorted color, and all of them fade with time, therefore a color profile included on a photograph permits the digitized recovery of original color of the object at the time the image was taken.
The use of photogrammetry, which has been sporadic in rock art survey work, has experienced a revival due to the introduction of digital elevation model (DEM) software. This can generate accurate three-dimensional recordings of petroglyphs. An alternative approach is the use of laser scanners to produce virtual digital models of great accuracy and versatility. Micro-topography of rock art has also been attempted with a CCD camera by obliquely projecting a grating fine grid over the rock art. The most time-consuming method of reproducing panels or sites is the production of physical rock art facsimiles. This has been sporadically used for many decades, but recent technological developments render the process much easier and more precise. Facsimiles are constructed by first acquiring the necessary topographic data, traditionally either by photogrammetry or the use of precision theodolites, but more recently by laser equipment. The rock panel is then recreated and the rock art projected onto it.
Archaeological age estimations, generated by considerations of style and “content”, have varied greatly for specific corpora. In the great majority of cases, they have been refuted by recent scientific dating work, suggesting that age determination of rock art by stylistic or archaeological means is tenuous at best. During the 1980s, this led to the replacement by forms of “direct dating”, in which the age of dating criteria physically and directly related to the rock art is determined. Propositions of the chronological relationship of these criteria with the rock art must be testable, i.e. refutable. The dating criterion may be of the same age as the rock art (e.g. an organic binder contained in the paint residue of a pictogram, or the fracture surfaces caused by the impact that occurred when a petroglyph was made); or it may be older than the rock art (e.g. its support surface, or a lichen thallus dissected by an engraved line); or it may be younger than the rock art (e.g. a superimposed insect nest, or a mineral accretion concealing the art). There are numerous types of such directly relatable criteria, most of which have been provided by geochemistry so far. However, direct dating offers no actual ages of rock art; it merely generates testable propositions about the relevance of specific physical or chemical data to the true age of rock art. The interpretation of this relationship demands an understanding of the method used, of the circumstances of sample collection, and of the limitations applying to stated results. The principal difficulty experienced with this approach is that the interpretation of its results is usually contingent on such complex qualifications that they are difficult to relate to immediate concerns of archaeology.
The first method used in this quest was radiocarbon analysis of mineral accretions containing atmospheric carbon, such as carbonates and oxalates. These are often found in direct physical relation with rock art, but the utility of their results is limited by a complex set of qualifications. Uranium-series dating (thorium-uranium) has also been applied to carbonate. Most widely used has been the carbon-isotope analysis of inclusions in mineral accretions or in paint residues, and the determination of the age of charcoal pigments. Here, the qualifications are somewhat simpler. In the former method, the principal limitation is that, to obtain valid estimates, the nature of the analyzed substance must be determined, either at the object or molecular level. Until recently, all such determinations referred to bulk samples, but in 2005, an Italian team succeeded in isolating the dated substance molecularly in rock paintings at five Libyan sites.
The determination of carbon ages of charcoal pictograms is a straightforward method, but unfortunately, the date refers to the time when the tree in question assimilated carbon from the atmosphere, not to the time of rock art production. Ancient charcoal might have been used in this, and often was, which introduces an obvious limitation to such results. The most reliable results from any pictograms so far are 137 carbon isotope determinations obtained from beeswax figures in northern Australia. An experimental approach is to use sand grains embedded in wasp or termite nests directly related to rock art to determine when they were last exposed to light, using the optically stimulated luminescence method.
Petroglyphs may be more difficult to date than paintings, because they offer no substance relating to the time of their execution. Nevertheless, the surfaces then freshly exposed and the mineral crystals broken or truncated experience significant changes over time, which are utilized in microerosion analysis. A very robust analytical method, it yields reliable dates for petroglyph manufacture, but they are typically imprecise and several preconditions need to be met. Recently, digital colorimetry has been applied to both repatinated petroglyphs and pigment pictograms, after surprisingly consistent results were secured from historical inscriptions of known ages. Other approaches, so far not effectively applied, would be to use lichenometry or rock surface retreat for estimating the ages of petroglyphs, or the use of weathering zone growth rates and macro-wanes. There is thus considerable scope for extending the range of viable direct dating methods.
Present indications of rock art ages suggest a significant increase of quantity during the early to mid-Holocene, perhaps 7000 or 6000 years ago. Large corpora in arid regions begin simultaneously around that time, which is almost certainly a phenomenon of selective preservation rather than an indication of cultural practice. In temperate regions, large bodies of surviving rock art first appear by the Neolithic or Bronze Age, where local lithologies are suitable. More arid regions, weathering-resistant rock types and well-sheltered sites have sometimes preserved remnants of much older traditions. Therefore the temporal distribution of rock art is universally related to preservation issues, especially those of lithology and climate.
While the scientific study of rock art may still be in its infancy, it is not limited to issues of antiquity. Investigations of the technology of rock art have involved several productive approaches, including the study of the tools used in making petroglyphs, of paint recipes, of microscopic inclusions found in paint residues, and of the sourcing of pigment materials. Nano-stratigraphy—the microscopic excavation of strata of paint residues, mineral accretions or weathering and patination zones—was first introduced in the 1970s, and has been developed to great sophistication already. Its principles are rather similar to those of archaeological stratigraphy, but its methods, obviously, are very different. To some extent, this method might even overcome the limitation of rock art being, in contrast to archaeological sediment strata, apparently two-dimensional.
Various other issues have been explored by rock art science in recent decades, such as the establishment of criteria for the effective discrimination between humanly made rock marks and natural markings on rocks. This had previously been a major problem, resulting in hundreds of cases of misidentification of both types of rock markings. Most of these mistakes refer to petroglyphs and natural markings resembling them, but there are also a few prominent cases of pictogram misidentifications on record. One of the most promising areas of scientific investigation of rock art concerns the holistic analysis of its physical, cultural and cognitive contexts. This includes the examination, often by field microscopy, of traces related to the production of rock markings, especially in well-preserved condition (particularly in caves). The methods used closely resemble those of forensic science (matching of microscopic striae, identification of microscopic organic traces and so forth), and are designed to determine the gestures involved in making the rock art. Their results can be correlated with other evidence in the same context (e.g. subterranean mining of flint and possible medicinal use of speleothems, or probable indications of ritualistic behavior. Some examples of the latter are the intentional placing of cave bear bones or other objects, or the systematic marking of cave walls by deliberate activities not yielding rock art.).
The interpretation of rock art
Traditionally, the greatest preoccupation of rock art researchers has been to interpret the iconography of rock art, i.e. what it is thought to depict, its meaning and its cultural role in ancient societies. Stylistic sequences were based on this approach in most world regions, and were refined and honed by successive scholars. Its basis was the plethora of stylistic genres perceived by the leading researchers, often constructs of a tenuous nature.
According to one of these models, the cave art of western Europe developed from the most simple to the most complex and ornate styles, from about 35,000 to 10,000 years ago. This fundamental tenet, and with it the stylistic chronology of Ice Age cave art, fell with the 1994 discovery of Chauvet Cave, and the subsequent dating of some of its ultra-sophisticated rock art to about 32,000 radiocarbon years (well over 35,000 sidereal years, due to the Campanian Ignimbrite event). This demonstrated the inexpedience of simplistic evolutionary schemes in the interpretation of Pleistocene art traditions.
Moreover, there are significant limitations to our access to such intractable dimensions of rock art as its meaning. Most rock art motifs are not adequately detailed naturalistic depictions of objects to permit reliable identifications, and such pronouncements are almost never testable for pre-historic rock art. The only blind test ever conducted of the ability of an alien researcher to effectively identify meaning in rock art occurred in northern Australia in 1977. A professor of anatomy showed that he himself had misidentified 90% of a body of animal and human depictions at the site Beswick Cave, after he became aware that the artists were still alive. He also reported that to correctly associate and integrate individual motifs into a whole to express the purpose and thought context of the paintings was totally dependent upon direct cultural information. Such access is of course impossible to pre-historic cultures; therefore, it would be imprudent to rely on the “identifications” of scenes, figures or artistic intentions by contemporary scholars posing as experts. Our own perception does not define reality, and even less can it define the realities perceived in other cultures. Our interpretations are freestanding constructs involving autosuggestion, reflecting our interpreting intellect and perception. They are not necessarily false, but their veracity is untestable and on balance they need to be regarded as reflections of the way we interpret reality—which we need to assume differs from the reality construct, cognition, and visual or mental perception of the now mute rock artist.
Valid ethnographic interpretation of rock art is very limited indeed, and is largely restricted to Australia, although a few isolated cases elsewhere are known. It has been given much less prominence than the fanciful interpretations of rock art by humanist scholars, which usually involve shamans, trance visions, space travelers, rituals, religion, head-hunting, cannibalism and a whole gamut of less entertaining variations. These interpretations provide insights into the perception, cognition, and cultural and academic conditioning of the interpreter. Because of the inadequate state of rock art dating we can in most cases not even know which period, culture and people the rock art in question is attributable to, yet often these tenuous interpretations are used as the basis of estimating rock art age.
Other forms of rock art interpretation have been neglected but are more promising. For instance, semiotic analysis to examine the syntax of rock art seems viable, and the study of work traces and of contextualizing rock art within spatially related evidence of other activities is most promising in cave sites. This may include the reconstruction of the gestures involved in creating the rock art. Psychological interpretation, for example in terms of graphic universals, is likely to yield testable information. As in all areas of rock art research, there is much room for improvement, which is precisely what renders this discipline so exciting and promising.
Rock art and semiotics
Recently, a trend has become evident in rock art research to explore the cultural and cognitive development of humans through rock art, especially of the Pleistocene period. Cognitive evolution, informed by advances in neuroscience and psychology, is increasingly becoming relevant to the understanding of the earliest art. Pleistocene rock art and portable art-like productions can provide evidence that may help test particular models as to how human cognition may have developed. As research into cognition and neuroscience continues apace, rock art and other paleoart are becoming primary data sources in this quest. Underlying principles and universals need to be identified, and the available material of the Middle and Early Upper Pleistocene requires much more attention than has been evident in the 20th century. This reflects a change from traditional preoccupations to new approaches. It will endeavor to place Ice Age paleoart into the context of cognitive evolution, explore its semiotic dimensions, and consider implications for technology and culture during the Paleolithic period.
In exploring our cognitive origins we need to appreciate that hominins did not become human through the natural processes that modified their skeletal architecture, but through processes enabling them to develop culture, cognition and technology on a scale removing humans far from all other primates in those areas. However, archaeologists and paleoanthropologists have provided us with a history of the human ascent that focuses very much on the physical evolution of hominins. By comparison, almost no effort has been directed towards learning about their cognitive and cultural evolution. It is therefore quite right to say that the reasons for humanization and the processes involved have so far barely been considered, and most certainly they have not been clarified. Culture is scientifically defined as the passing on of practice by non-genetic means (i.e. by learning), and is therefore practiced not only by humans, but also by many other animals, especially primates. “Biological intelligence” does not necessarily lead to a better grasp of objective reality for the species concerned. While it is true that intelligent forms of life must participate in a process that inevitably leads to the evolution of more intelligent forms of life, the improvements will always be in terms of their ability to enhance access to energy and nutrient resources, and to promote procreational potential, never in terms of facilitating a better grasp of reality. Genotypes determine the sensory faculties of an organism, and changes only occur within the confines of phenotypic plasticity. These abilities determine which material stimuli an organism can detect. Genes can also form neural circuitry that allows cross-referencing of sensory information, but the ability to construct conceptual models of reality, which defines “intelligence” biologically, is not itself genetically determined. Among highly advanced life forms, selection will favor organisms capable of the conceptual and behavioral innovations from which new behavioral modes can be constructed: the mental faculties, not their constructs, are the selective determinant. Similarly, cortical or speech-related structures are results, not causes, of evolutionary selection favoring speech (applied symbolism) or intelligence: a selection criterion needs to be established before it can affect phenotypic selection of genes.
The introduction of phenomena consisting only of humanly perceptible variables, such as the production of symbolic surface markings, rendered perceived “reality” conceptually manageable, by providing complete rather than fragmentary sets of percepts. Visual and mental taxonomizing processes and the inclusion of the new neural structures in cybernetic feedback systems thus became available for selection. “Conscious experience”, or rather what we understand by it, became possible because the neural facilities prompted by earliest paleoart production became available for the processing of stimuli of the non-artificial material world, in a taxonomizing format.
Human knowledge is thus derived from applying concept-building cognitive processes to external stimuli, i.e. sensory information, thus accumulating percepts. It is self-evident that human knowledge has a tendency of reinforcing itself through its own products, because it is continually validated and augmented by our material and cultural achievements. Cultural dynamics refer to the processes by which the intelligent organism alters its perceptible environment through its dialectic participation in the processes shaping it. Selection in favor of increased levels of “intelligence” is the inevitable outcome of such interaction among percepts, concepts and behavior patterns, but at no stage of this autonomous process is there any need for the concepts to be in tune with objective reality. Provided that the internally consistent logical framework is not challenged by it, there is no reason to assume that an entirely false, cultural cosmology or epistemological model could not be formed and maintained indefinitely by an intelligent species. Evolutionary success is irrelevant to the objective merits or validity of such models. The concepts of reality that have evolved in the course of hominin and human history have led to the one apparently held by all extant human populations. There is no reason to assume that these concepts could be particularly useful in exploring objective reality.
The simplistic view that the animal figures in Ice Age art are cognitively more sophisticated than the often highly complex “geometric patterns” found in Pleistocene arts is easily refuted. If we separate art works into three-dimensional figurative, two-dimensional figurative and non-figurative genres, we see that the first is the least complex and the last the most complex. This is because in the first art genre, referent (the object depicted, the signified) and referrer (the art motif) are cognitively relatable by direct visual resemblance of certain characteristics. In graphic figurative art, the referent is related to the art motif through the projection of certain of its characteristics onto a two-dimensional plane, so the perception of its relationship to the referrer involves a decoding process requiring certain cognitive faculties. In entirely non-figurative arts as well as those that use highly “stylized” versions of iconicity it is impossible to know the referrer, unless one has direct access to the cultural conventions in question. Moreover, in the last-named art form, concepts or ideas involving no figuratively definable referents can readily be “depicted”. It is therefore clearly the semiotically most sophisticated art genre, and can communicate unlimited numbers of ideas, in rather the same way as written characters.
This separation can be correlated broadly with the main stages of symbolic evolution. The Makapansgat cobble, an object almost three million years old, seems to indicate an early hominin ability to detect at least some aspects of iconicity, even if only at a “reflexive” level. It would then be reasonable to consider that subsequent hominins developed the capacity to detect iconic properties of natural objects (such as the Tan-Tan and Berekhat Ram pebbles). A predilection for abstracting three-dimensional likeness to graphic image apparently developed more recently, perhaps preceded by an ability to replicate two-dimensional imagery, such as phosphenes, fossil imprints and, in some traditions, eventually tracks. The use of non-iconic markings to form complex patterns of communicable meaning seems to originate in Middle Paleolithic traditions of Africa or Asia, on present evidence. This last art form, the most sophisticated, dominates in most of Upper Paleolithic Eurasia. Even in the western European cave art, “non-figurative” motifs far outnumber zoomorphs, and since they are almost certainly symbols of specific meanings, they are more semiotically complex than the usually favored animal figures. An animal picture, by itself, communicates very little by comparison, but it has been much more likely to attract scholarly attention. By Upper Paleolithic times, traditions of using non-iconic markings had become so sophisticated that they appear to have served for mnemonic, record-keeping or other exceedingly complex semiotic activities, e.g. in Russia and Siberia. Their vestiges have so far attracted only cursory attention and these traditions remain profoundly unknown.
The semiotic dimensions of early rock art and other paleoarts thus remain under-explored, yet they could offer valuable insights into how we as a species formed constructs of reality and created our world. It is of utmost importance to the human species to develop this aspect of semiotic studies.