Consciousness, Literature and the Arts
Archive
Volume 11 Number 3, December 2010
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Social Mirror Theory, the Arts, and the Evolution of Human Self-Consciousness
by
University College London, University of Westminster
The human difference
A recent major article in Current Anthropology (Henshilwood & Marean, 2003) pointed out that a central problem in palaeoanthropology (the study of human evolution) is that behavioural scientists have failed to produce any coherent body of theory defining ‘modern human behaviour’ and how, if at all, it differs from the behaviour of other animals. Despite not knowing what modern behaviour is, palaeoanthropologists still want to know when it began. To this end, they use an assortment of traits without any known relationship to each other which are thought to be indicators of ‘modern behaviour’. Examples include burial of the dead as a sign of ‘symbolic ritual’; art and ornamentation as evidence of ‘symbolic behaviour’; the ‘symbolic’ use of red ochre; worked bone and antler; standardization of artefact types and artefact diversity; use of harsh environments; fishing and fowling; etc.
There is obviously something wrong with this list. How many people today use red ochre, carve bone and ivory, go fishing and fowling, or live in harsh environments? These are contingent variables, not defining features of human behaviour. There are constant arguments about whether one trait or another does or does not indicate ‘symbolic behaviour’ or ‘higher cognitive functions’. The arguments never reach any resolution because no one has any clear idea of what the terms mean, what the traits indicate, or how the traits and the terms relate to each other.
Collective deceptions
How is it possible that self-conscious modern humans do not know what modern human behaviour is? Stranger still, how can self-conscious modern humans who just happen to be behavioural scientists not know what modern human behaviour is?
My children seem to know, because they watch Bugs Bunny cartoons and laugh in all the right places. Much of the humour in such cartoons depends on animals behaving like humans, and our implicit knowledge that this is absurd.
So the problem cannot be one of simple ignorance. The failure to define human behaviour can only be the result of collective deceptions. It is the job of all human cultures to falsify our understanding of ourselves. That is the only way that the first human culture could have coerced our social but selfish ancestors into collaborating in a non-selfish system.
Collective deceptions are always political in origin. For example, the physicalist paradigm arose from the need of Enlightenment scientists to break the Church’s monopoly on the Truth market (Jordanova 1980). Today materialistic science gets the big funding because it legitimates the materialist ideology of capitalist societies. Equally political are all the other collective deceptions that get in the way of rational science – cognocentrism, logocentrism, individualism, and genocentrism (Whitehead 2006).
Cognocentrism and logocentrism
The notion that ‘intelligence’ and language are our most distinctive accomplishments and the reason for our very large brains, has proved remarkably persistent despite contrary evidence. As long ago as 1884, Sir Francis Galton, from an examination of 9,000 visitors to the London Exhibition, found to his great disappointment that eminent British scientists could not be distinguished from ordinary citizens on the basis of head size (Atkinson et al, 1993: 458). The cortical areas most expanded in humans can suffer massive lesions without impairing intelligence (Lishman 1998). Hydrocephalic individuals with only a thin rind of cortex lining their skulls may have high intelligence quotients (Walker 1993), and you can even remove the entire right hemisphere without affecting IQ (Gazzaniga, 1985). Similar arguments apply to language. Microcephalic dwarves may have good language skills (Walker 1993), and, despite their much smaller brains, Congo grey parrots can learn to speak several hundred English words and construct grammatical sentences (Pepperberg 1999).
Since 1993 several studies have investigated correlations between brain size and intelligence (Andreason et al., 1993 ; Egan et al., 1994, 1995; Peters, 1995; Rushton & Ankney, 1995, 1996, 2000; Vernon et al., 2000; Drachman, 2002), in some cases including measures of specific brain components (Flashman et al., 1998; Thompson et al., 2001; MacLullich et al., 2002; Staff, 2002). A meta-analysis of 37 such studies, involving 1,530 people, yielded a best estimate for the population correlation (r) of 0.33 (McDaniel, 2005), suggesting that the intelligence factors measured are associated with around 11% (r2) of brain volume, and cannot account for the bulk of brain expansion during the last 2.5 million years.
Social intelligence theory
The dominant hypothesis currently purporting to explain brain expansion in primates is the social intelligence or ‘Machiavellian intelligence’ hypothesis. This holds that primates, including humans, have relatively large brains because of a selective premium on social rather than object intelligence. Social intelligence requires more brain power than object intelligence for the simple reason that when you push an inanimate object around, it doesn’t try to push you back. There is nothing wrong with the logic here, as far as it goes, and at least the hypothesis has the virtue of being social – but it is still cognocentric, and does not explain why certain neocortical areas are more expanded than others in humans, or the sequence in which these expansions occurred.
Figure 1. Human and monkey brains (Brodmann 1909)
Differential expansions of human neocortex
There is a tendency to assume that brains are self-evidently useful and that bigger must always be better. However, brains are physiologically and metabolically expensive (Aiello & Wheeler, 1995). The human brain represents a mere 2% of total body mass, but takes up 25% of oxygenated blood from the left ventricle and 20% of the total energy consumption of the body. Our large brains also require high levels of dietary lipids especially when growing. Such high costs must be recompensed by specific benefits. Brain asymmetries (prefrontal larger in the right hemisphere, parietal and occipital larger in the left) indicate that brain expansion is never profligate: expensive brain tissue always has to earn its keep.
Classic drawings by Korbinian Brodmann (Figure 1) clearly show which parts of the human cortex are most expanded relative to those of a monkey. Bear in mind that the monkey brain here is greatly enlarged for ease of comparison. So, for example, primary visual cortex – Brodmann’s Area 17 – looks enormous in the monkey brain, and tiny in the human. But the two are actually the same size. The most massive expansions affect prefrontal and inferior parietal cortices, and the temporal poles.
Similar differences are also apparent when we consider our nearest relative, the chimpanzee. The average adult human brain is around three times larger than that of the average adult chimp. But this ‘three times larger’ is not made up of uniform expansions of all brain areas (Figure 2):
1. Primary cortices (pale buff) are not expanded at all, with the exception if primary auditory cortex, which is about three times larger than in a chimp. The expansion is bilateral, suggesting an adaptation for song rather than speech.
2. Secondary areas (darker buff) are more evenly expanded, being around two to three times larger than those of a chimp. But this hardly explains the overall three-times-larger expansion of the human brain.
3. Major expansions (red) are restricted to three areas. Firstly, prefrontal cortex is more than six times larger than in a chimp. Secondly, temporal areas – notably the poles – are also massively expanded (indicated by question marks because allometric scaling figures are not available). Thirdly, the inferior parietal lobule might be regarded as ‘infinitely expanded’ since there is no unambivalent ape homologue. Inferior parietal cortex is strategically placed for multi-modal integration – surrounded on all sides by sensory and motor cortices – and, unlike ape parietal cortex, it only talks to other higher cortices including the prefrontal lobe (Lishman 1998).
Figure 2. Neocortical expansions relative to chimp (based on Deacon 1992)
Social mirror theory
The pattern of cortical expansions in the modern human brain is not consistent with cognocentric or logocentric hypotheses of brain expansion. A better alternative is social mirror theory, originating over a hundred years ago with Wilhelm Dilthey (1883-1911), James Mark Baldwin (1894), and George Herbert Mead (1934). After decades of relative neglect, social mirror theory is now attracting renewed interest as a result of research into autism and ‘theory of mind’ (the ability to interpret behaviour in terms of epistemological mental states such as knowing, believing, imagining and dreaming) (Moses 1994). The theory holds that mirrors in the mind depend on mirrors in society (Whitehead 2001). That is, you cannot learn to pay attention to experiential states, and so become aware of them in yourself and others, unless they are first shared and made objective through social display.
There has been an explosive proliferation of social displays during human evolution. We humans have a formidable armamentarium of social mirrors which, according to social mirror theory, explains why we are so extraordinarily self-conscious. Human displays can be usefully classified into three types – communication, play, and performance – all of which come in three modes – implicit (displays of desire, affect, and intention), mimetic (intentional representations based on resemblance), and conventional (everything shaped by human economico-moral culture). The table below shows some common forms of display classified in this way (Whitehead, 2001).
Three modes of communication
Gesture-calls (implicit mode) include facial expressions, body language, vocalizations, and even secretions such as tears, which project affect, desire, and autonomic states (e.g. tiredness) into a public arena (Burling 1993).
Iconic gestures (mimetic mode) draw pictures in the air; iconic vocalizations mimic real sounds, such as squealing brakes and police sirens (ibid). Unlike affective gesture-calls, iconic gesture-calls are under voluntary control, and can be used to deceive. So mimesis cannot evolve until there is a sufficient degree of social trust or sanctions against deception.
Analogical codes (conventional) include musical scores, pictographic writing, and town hall clock faces. Cryptic codes include language, phonetic alphabets, mathematical denotations, traffic signals, and so on (ibid). Economico-moral codes are accepted standards of behaviour – which prompt parents to tell their children that they are ‘good’ or ‘clever’, so coaching them for social and economic success (Trevarthen 1995).
Three modes of play
Communication obviously differs from play. Communication is goal directed – manipulative and so political (Krebs & Dawkins 1984) – whereas play is not (Turner 1982; Apter 1982). Play is exploratory, engaged in ‘just for fun’, and takes place in its own ‘space-time’ (Huizinga 1955; Winnicott 1974) – like an experiment in a laboratory – where activities and social scenarios can be tried out without real-world risk (Turner 1982).
Play may be divided into embodied forms – exploring and enjoying the potentials of the body and simple social relationships – and two submodes of pretend play: projective and introjective (Winnicott 1974; Jennings 1990). An example of projective play would be pretending that a pen is an aeroplane, whereas the introjective or role-play equivalent would involve pretending that I am an aeroplane. Over and above these basic modes are a variety of conventionalized forms such as games with rules.
Three modes of performance
Performance is best understood as a playful extension of communication. Performance and communication are hardly distinguished in psychology and cognitive science. Music psychologists, for example, frequently regard music as a kind of language for communicating emotion (Sloboda 1985). We simply do not need music for that – our gesture-call system already tops the primate charts for eloquence and complexity in the communication of affect (Young 1992). Music cannot be sufficiently specified in emotional terms, and may not ‘express’ anything at all (Storr 1993). It is more like massage – the pleasure is intrinsic to the performance.
Both communication and performance are goal directed and manipulative, but performance has additional functions, namely, grooming and entrainment. Take song-and-dance displays for example. The term refers to the kind of sonic and balletic displays which are seen in various mammals and in human babies around three months of age (Trevarthen 1995). Gelada baboons have choral displays in which voices are synchronized with microsecond precision (Richman 1978). Synchronized vocal and balletic displays, as in dolphins for example (Connor 1992), cement the alliance between co-performers – the grooming function – and unite them into a volitional and experiential unity – the entrainment function. Performative displays turn two or more selfish individuals into one great big selfish individual – which can be pretty formidable, as in Nuremberg rallies and the like.
All the cultural arts come under the heading of performance, but I will just mention a couple that might be conceptually less familiar. Emblems include corporate logos, national flags, national anthems, and sacred icons such as crucifixes and rainbow serpents. Economico-moral exchange includes institutions of reciprocity such as marriage, gift-exchange in animistic societies, capitalism in our own, and other forms of reciprocity not recognized by professional economists, such as sporting contests, warfare, and terrorism.
The most salient feature of human life is social display. People who spend perhaps 35 hours of obligatory role-play at work may spend as many hours watching voluntary role-play on television. We decorate our homes, turn the plots of land around them into gardens, and take care over the presentation of food to our guests. That is, we turn almost every aspect of our lives into wealth displays. Baroque churches, famous paintings, PhD diplomas, sporting trophies, and even the rags of the penniless ascetic, are all displays of material, intellectual, moral, aesthetic, or spiritual wealth (Bourdieu 1972).
Social displays as a phylogenetic sequence
All these displays could not have emerged all at once during human evolution, and must have evolved in a logical order.
Communication has to be the oldest type of display (even cells ‘talk’ to each other in chemical languages). If performance is a playful extension of communication, then there must be an arrow of evolutionary sequence from communication through play to performance (Figure 3).
Equally, the implicit mode has to be older than mimesis, and both have to be in place before they can be conventionalized by economico-moral culture, so that gives us a ‘down’ as well as an ‘across’ arrow.
If play and performance generate the necessary preconditions for voluntary as opposed to involuntary signals – self/other-awareness (Gopnik & Meltzoff 1994) and cooperative trust (Whiten, 1993) – then we would expect an evolutionary spiral from implicit communication (top left in Figure 3) to conventional performance (bottom right):
This is an extended version of a theory proposed by Emil Durkheim (1912). Durkheim argued that you cannot have language (conventional communication) until you have ritual (mimetic performance), because language is syntactical and you only need syntax for displaced reference – to refer to things imagined or imaginary, as opposed to things present in the here-and-now for everyone to see, hear, touch, or smell. How can you encrypt an intangible, Durkheim asked, unless it is first made public through some kind of conventionalized pantomime? Linguisticians have further argued that you cannot have language without a moral framework (Grice 1969; Austin 1978), because words are cheap, and it is too easy to lie (Knight 1998). For most social anthropologists, this too implicates ritual.
The spiral co-evolution of social displays and self/other awareness is broadly supported by comparison across animal taxa and child development literature (Whitehead 2003). This evolutionary spiral also predicts three ‘rubicons’ during human evolution:
Figure 3. Spiral evolution of social displays
1. The first, triggered primarily by the emergence of song-and-dance display, would be characterised by expansions of all secondary sensory and motor cortices and the inferior parietal lobules. Synchronised choral displays would also predict expansions of Broca’s and Wernicke’s so-called ‘speech’ areas, and possibly primary auditory cortex. This would lead to increased self/other-awareness at the level of affect and social relations.
2. The second, driven by increasing sophistication of pretend play, would lead to further expansions of song-and-dance areas, plus the prefrontal lobes, associated with the development of ‘theory of mind’ and ‘theatre of mind’ (the ability to run social scenarios in imagination: Whitehead 2001).
3. Finally, the emergence of modern culture would lead to a reduction in brain size, because a society coordinated by economico-moral rules would be less dependent on displays such as song-and-dance for grooming and entrainment. Since language employs digital coding, in contrast to affective and mimetic signals which are analogical (having infinitely variable sliding scales of magnitude, volume, rhythm, tone, pitch, timbre, etc: Burling 1993), the emergence of language would also be expected to lead to some reduction in cortical size. We know, for example, that processing pitch, as an aspect of prosodic intonation, involves more neocortex than semantics and syntax (Brown, 1991), and American Sign Language – which is more mimetic than speech – engages considerably more neocortex, mainly in the right hemisphere (Neville et al. 1998). The remarkable command of spoken English demonstrated by Alex, the Congo grey parrot (Pepperberg 1999), will hopefully help to speed the overdue demise of the logoparadigm. Modern culture is associated with collective deceptions and economico-moral personae – collectivized and fetishized perceptions of self and others (Whitehead 2003).
Why do we have large brains?
Expansion of all secondary and higher cortices implies a comprehensive increase in behavioural complexity. It seems reasonable to assume that our large brains are an adaptation to what we do best – social display. There are at least four reasons why ‘play and display’ should lead to brain expansion:
1. Multi-modal control and feedback demands are high in all kinds of performative displays, especially song-and-dance and role-play.
2. Timing precision: Musical and dance performance in particular involve timing precision which is finer than the firing times of single neurones (Richman 1978). Calvin (1983) has shown that such precision can only be achieved statistically – through massive ‘neuronal redundancy’. It is probably no coincidence that dolphins, whose balletic displays also involve fine timing precision, also have very large brains.
3. Acquired skills lead to expansions of the cortical areas involved (Karni et al. 1995). In ’cello players, for example, cortical representations of the fingers of the left hand are larger than those of the right (Elbert et al. 1995). Our capacity for acquiring an extraordinary range of motor and perceptual skills, as evidenced by athletic as well as artistic and technological performance, is a striking feature of human versatility
4. Role-play and social imagination require the brain to model multiple minds/brains in parallel (the chimerical brain hypothesis: Whitehead, 2003; cf. Oakley & Eames 1985; Hilgard 1986; Bliss 1986; Laughlin et al. 1992; Mitchell 1994). At the very least, role-play and pretend play more generally require the metacognitive ability to represent representations.
These four factors would seem to be less critically necessary for communication per se, because, for example, affective and iconic gesture-calls are less complex and require less timing precision and skill than dance movements. Human adaptations conventionally attributed to communication seem more specialized for performance e.g. the tonal range of speech (roughly a musical fifth) grossly under-employs our highly tuneable pharynx (with a tonal range of at least two octaves, and two or more `registers' or `gear shifts' in intensity and pitch: Doscher, 1994). The human pharynx resembles an analogical musical instrument, with infinitely variable pitch – an adaptation for song rather than digital speech.
The above considerations support the hypothesis that ‘play and display’ were significant factors in hominid brain expansion, and do not support the hypothesis that language and ‘general intelligence’ (or tool making, hunting skills, etc.) were equally or more important. Language might even be expected to lead to a reduction in brain size.
Brain expansion during human evolution
Let’s look at the expansion of the human brain over the last 3 million years, and archaeological evidence for social display and self-awareness. The major hominid groups I will discuss are illustrated in Figure 4.
1. The australopithecines – apiths for short – were the first truly bipedal apes. Figure 4 shows a reconstruction from Lucy (Australopithecus afarensis) – a near complete skeleton. She is around 1meter tall. The arms are as long as the legs and the rib cage is conical – both adaptations for swinging through the trees. But the legs and pelvis are adapted for bipedal locomotion in more open territory – as directly evidenced by the Laetoli footprints in fossilized mud around 3.5 million years old (Leakey & Hay 1979).
2. Habiline fossils are too fragmentary to show a reconstruction, and highly variable. Some specimens have relatively human-like crania with ape-like bodies; others have ape-like crania with human-like bodies – suggesting a mosaic of traits evolving in parallel in different habiline species. The name Homo habilis means ‘handyman’ and the hand is very modern – capable of both power grip and precision grip – less adapted to brachiation (swinging from branches), but well suited for making and using tools. Note that the cranium is well rounded.
3. The Nariokotome boy illustrated above is an early specimen and one of the most complete erectus grade fossils. His dental age is 11 years but he is already almost 6 feet tall (Walker 1993). That indicates a relatively ape-like pattern of growth – with minimal extension of childhood – in other words, little opportunity to develop pretend play to any greater degree than has been observed in chimps. Homo erectus was the first hominid to leave Africa.
4. In Europe and western Asia Homo erectus evolved into Homo sapiens neanderthalensis, and in Africa into Homo sapiens sapiens – anatomically modern humans. Modern humans – especially females – are much more gracile than Neanderthals, reflecting a more leisurely life-style. There is evidence that Neanderthals pursued a baboon-like hunting strategy, with entire communities trekking around the landscape in search of food. Stress and other bone data suggest that Neanderthals frog-marched their children on arduous daily manoeuvres (Trinkaus 1992, 1993; Ogilvie et al. 1989). Anatomically modern humans, on the other hand, appear to have had a gendered hunter-gatherer division of labour, allowing mothers and children to remain near the home base, where children would have sufficient leisure to develop pretend play skills to a greater degree than Neanderthals. It is possible that Neanderthals lacked some associated aspect of self/other-awareness, such as ‘theatre of mind’.
Now, if we look at the process of brain expansion over time, we see that it did not occur at a steady rate (Figure 5). As predicted by social mirror theory, there are three ‘grade shifts’ during human evolution – periods of accelerated change in anatomy and brain size – and they are in the predicted direction.
Apiths evolved into the more robust pithecanthropines over a period of 3 million years or more, with cranial capacity remaining relatively constant at around 400 cc. But between 2.5 and 2.0 million years ago, during the habiline radiation, brain size approximately doubled to 800 or 900 cc. This was followed by a long plateau of anatomical and behavioural stasis lasting some 1.5 million years, and then brain size again doubled within the last half million years. Finally, brain size declined to its current level of around 1,350 cc. This U-turn, predicted by social mirror theory, but problematic for cognitivist theories, probably followed the emergence of economico-moral culture.
Figure 6. Earliest appearances and durations of stone tool technologies
What archaeologists would like to see – but don’t – is periods of brain expansion followed by noteworthy advances in stone-tool technology, reflecting the increase in ‘intelligence’. This expectation combines cognocentrism with post-industrial ideas of ‘progress’. But we do not attribute the industrial revolution to ‘increased intelligence’. Apes can make Oldowan-type tools but have no real use for them (Wright 1972; Toth et al. 1993). Chimpanzee tools vary regionally, and there is no need to regard any technological change as other than historic. It is also wrong-way-round thinking. Animals do not evolve carnivore teeth and then decide it might be a good idea to eat meat. New behaviours arise first for environmental reasons, and then anatomical change follows with genetic adaptation to the new behaviour.
Stone tool technologies do not correlate with brain expansion, with the exception of the very first unequivocal stone tools around 2.7 million years ago, just before the first period of brain expansion (Figure 6). What is significant about these earliest tool sites, at Hadar and Omo in Ethiopia, is that they are all riverside sites. Early hominids did not possess fire for protection from predators, and if you are a prey animal, you do not want to linger near drinking water, still less sit around knapping stone tools and using them to butcher nice savoury-smelling meat (Potts 1994). That is asking for trouble. We know that Apiths were sometimes eaten by leopards, because we have skulls punctured by leopard teeth. But the first stone tool makers - probably no taller than Lucy - were evidently not afraid of such dangerous predators.
Changes in brain anatomy
Before considering the full significance of this, let’s look at structural brain changes across this evolutionary span. Figure 7 shows some endocasts taken from various crania. They lack a great deal of surface detail and there is no internal anatomy of course. The first cast is taken from a modern chimpanzee for comparison. The next two are early and later Apiths – africanus and robustus. They are very slightly larger than the chimp example, but the main difference is increased height and width, and a more rounded shape with less front-to-back and top-to-bottom tapering (Holloway 1974; Tobias 1987). This reflects significant expansion of mainly temporal and parietal cortices, possibly with some premotor expansion.
I don’t have a picture of a habiline endocast but the same trend continues – brains become more fully rounded with increased height and width, and expansions of secondary cortices. From an examination of six habiline crania Tobias (1987) – the discoverer of the first Homo habilis type-specimen – notes a modern pattern of asymmetries, the first appearance of an inferior parietal lobule, and prominent Broca’s and Wernicke’s ‘speech’ areas. From the latter he concludes that Homo habilis could speak.
Figure 7. Endocranial casts (after Holloway, 1974)
The Homo erectus brain is simply the end-point of the habiline changes, with considerably increased length, but no obvious enlargement of prefrontal cortex. The last example – from a contemporary human – shows further rounding, increased expansion of premotor, temporal, and parietal – especially inferior parietal – cortices, and, for the first time, major expansion of the prefrontal lobes.
All these changes are consistent with the emergence of song-and-dance display in the first apith tool-makers, escalating song-and-dance display during the habiline radiation, a highly conservative song-and-dance culture in Homo erectus, further expansion of song-and-dance during the second grade shift, together with a major increase in mimetic display and pretend play. That is, the changes are consistent with a ‘play and display’ hypothesis of brain expansion, whereas cognocentric hypotheses have little to say about these specific changes.
Evidence for social display and self-awareness
To explain the above sequence of brain changes we need two things:
For the first two grade-shifts, evidence of a new concentrated food source capable of lifting the nutritional and metabolic ‘lid’ on brain expansion
Evidence of behavioural change just before each grade shift
The first grade shift
The earliest stone tools at 2.7 million years ago tell us, first of all, that these early hominids were butchering meat, an essential nutritional substrate for brain expansion. Butchery indicates levels of social trust unprecedented in any non-hominid primate. There is no way chimpanzees, for example, could butcher meat. When modern chimps catch a colobus monkey, they tear it apart and start eating it whilst it is still alive. That is because they don’t trust each other. They are grabbing their share of the meat before the others eat it. The fact that the first tool-makers butchered their meat close to drinking water also indicates highly cooperative behaviour, since they were not afraid of predators.
These early sites have not been adequately investigated, and I can make my points more clearly using an early Oldowan site. This dates to a period closely following the first brain expansion, and provides clues to the behavioural changes across this first grade shift. Figure 8 is a sketch map of a type C Oldowan site from the oldest archaeological level at Olduvai Gorge in Kenya.
Oldowan sites are characterized by broad scatters of bone and stone about 10 to 20 meters in diameter, indicating that Oldowan hominids carried quantities of stone and meat repeatedly to the same sites for tool-making and butchering purposes, over a long period of time. The brown blobs in Figure 8 represent six butchery scatters positioned roughly 2 km apart and 2 km from a central rocky outcrop, the source of all the stone at the site, and forming a near-perfect hexagram (Potts 1987).
What this shows is that Oldowan tool-makers were very busy hominids, prioritizing time-and-motion above all other factors, including predation risk. The most risky sites here are those next to water and the one surrounded by bush cover – where anything can sneak up on you unseen. These are not hypothetical risks. Oldowan butchery scatters, continually smelling of blood and meat, were repeatedly visited by dangerous social carnivores such as lions and hyenas. Some butchered bones have Oldowan tool marks overlaid by lion teeth marks, others show the opposite sequence – tool marks overlaying teeth marks. These hominids apparently pursued a life-style of confrontational scavenging, successfully outfacing cooperative predators despite the latter’s huge advantage in terms of claws, teeth, and muscle. This could only be achieved if the hominids operated in larger and/or better-coordinated groups.
Figure 8. Oldowan butchery scatters surrounding a rock source at Bed 1 Olduvai
If they were anything like modern primates, they would have staged a loud and vigorous display when threatened by predators – such as could loosely be described as ‘song-and-dance’. Furthermore, I would argue that these early tool makers must have had elaborate song-and-dance displays because they simply did not have time for anything else.
Robin Dunbar (1993) has shown that, in modern primates, there are straight-line correlations between absolute brain size, group size, and grooming time. That is, primates living in larger groups need larger brains and spend more time grooming each other in order to service all the coalitions and alliances necessary for political survival and reproductive success. But there is a fixed limit on grooming time because resting, feeding, and journeying between food sources make irreducible time demands. The maximum tolerated grooming time in modern primates is about 20% of the daily time budget. Groups requiring more grooming time than that tend to become unstable and break up into smaller groups.
Aiello and Dunbar (1993) projected these findings onto ancient hominids and found that even the smallest-brained habiline in their sample was pushing the maximum grooming time limit (Table 2). But Oldowan hominids faced additional time pressures unprecedented in any primate before or since – carrying stone and meat around the landscape, making tools and butchering, confronting dangerous predators, and perhaps teaching their numerous skills to the young.
Habiline crania Cranial capacity Group size Grooming time
Largest 752 cc 92.12 25.67%
Smallest 509 cc 70.97 19.60%
Table 2. Predicted group sizes and grooming times based on two habiline crania
Dunbar points out the need for a time-saving substitute for one-to-one grooming. He calls this ‘vocal grooming’ and suggests this as a possible origin for language. But Durkheimian and linguistic arguments for a late origin for language suggest that ‘gesture-call grooming’ would be a better term – in other words, song-and-dance. Mothers today do not generally talk their babies to sleep – cradle songs and rhythmic movement are far more effective. Even the most flattering language cannot match the potential grooming power of song-and-dance.
The second grade shift
So we have suggestive evidence for song-and-dance display emerging just before the first grade shift, and well established by the end. What about the second grade shift? Here the evidence is overt and compelling.
Late Homo erectus began to collect useless objects apparently for aesthetic reasons – attractive pebbles, crystals, shells, carnivore teeth, fossils and fossiliferous cherts (a flint-like rock), often transported from sources several kilometres away (Oakley 1971, 1973, 1981). Collecting behaviour continues in unbroken succession throughout the second grade shift right up to the ‘cultural explosion’ of the Upper Palaeolithic (Hayden 1993). At Arcy-sur-Cure, for example, a Neanderthal site, there are collected fossils and pieces of ‘fool’s gold’ – some of them engraved; and at Combe Sunière, several large blocks of fool’s gold weighing 2-3 kg each, some of them brought from 30-90 km away. Other collected objects are associated, not with Neanderthals, but with modern humans, like the Glycimeris shells – an inedible species – at Qafzeh, brought from 50 km away. So collecting behaviour does not appear to be something which was ever extinguished in later hominids, but rather is a direct ancestor of contemporary collecting and wealth displays.
Not only did Homo erectus collect useless objects, but also used impractical materials for making tools, such as fossiliferous cherts (difficult to flake cleanly) and rock crystal (too fragile) (Hayden 1993). Acheulian handaxes are themselves of uncertain utility. They were impractical for use as ‘axes’ because all edges are equally sharpened, making them highly unsuited for use with a ‘power grip’. No one has yet suggested a function for their distinctive almond shape, except possibly as a throwing weapon, but their design template remained constant for 1.3 million years. It is possible that the ‘axes’ themselves served a social display function, on the basis of Zahavi’s handicap principle (the idea that an animal can demonstrate superior fitness by giving itself a handicap: Kohn 1999). Figure 9 shows two Acheulian handaxes with a central boss formed by a fossil in each case (Oakley 1981). Some kill-joy archaeologists argue that the central fossils had no significance to the makers (Noble & Davidson 1996), but this seems highly unlikely since late Homo erectus collected fossils and presumably had a social use for them.
Figure 9. Acheulian handaxes with centrally positioned fossils (Oakley, 1981: 208, 210)
Figure 10. Scoria pebble figurine from Berekhat Ram (Schepartz, 1993: 118)
The first putative iconic object (Figure 10) also comes from a late Acheulian site - at Berekhat Ram on the Golan Heights in Israel – associated with late Homo erectus or heidelbergensis, and dating to more than 270 kya (thousand years ago) (Feraud et al. 1983). This is a scoria pebble with a human-like shape, accentuated by an artificially engraved groove around the neck (Goren-Inbaar 1986). Archaeologists refer to this as a ‘figurine’, because they are conditioned to do so by familiarity with the Venus figurines of the Gravettian period, almost a quarter of a million years later. Our notions of ‘Art’ with a capital ‘A’ are distorted by the way religious and economic processes have turned art objects into wealth displays. But ‘art’ originates in childhood play, and it may be better to think of this object as a toy. Representational art could hardly emerge in any society unless children had been playing with dolls and other representational toys for some time before that.
There are no other examples of iconic representation from the Lower Palaeolithic, but one would not expect toys to be commonly made from such durable material as stone. Wood, leather, sand, clay, or even snow, are better suited to the spontaneous nature of play. What seems most evidential in this case is the fact that there is no naturally occurring scoria at the site, so it was presumably brought there (Marshack 1990).
There is, however, oblique evidence of pretend play during the second grade shift. Pretend play, in modern children, beginning at the age of 12 months, seems to be necessary for the emergence of self-esteem – the perception of the self in terms of social value – at the age of 2 years, when role-play ability also emerges. Autistic children, with deficient pretend play, fail to develop perception of the self as value. Further, dressing-up behaviour, beginning around the age of 5 or 6 years, is obviously dependent on role-play. Even self-adornment, which begins much earlier, would seem to be part of the same development of self-awareness. Homo sapiens is the only primate which regularly alters its own appearance.
Although evidence of self-adornment is infrequent, perforated teeth and bone for use as pendants are scattered throughout the Neanderthal record (Marshack 1990). A perforated swan vertebra and perforated wolf foot bone come from Bocksteinschmeide in Germany, dating to 110 kya; also a perforated bone fragment from Peche de l’Azé in the Dordogne, two perforated teeth from Bacho Kiro in Bulgaria, and a reindeer phalange and fox canine from La Quina in Charente.
At Hortus in Valflaunes Neanderthals hunted leopards and other big cats, presumably for their hides. The bones of one leopard suggested to the archaeologists that the hide had been removed in one piece – for use as a ‘costume’, they suggest. A hominid who valued and collected attractive and unusual materials could hardly fail to appreciate the difference between feline and bovine hide.
Perhaps the most interesting evidence for self-adornment is the use of red ochre and haematite, presumably for body paint, which appears at late Homo erectus sites from at least 300 kya – that is, before or at the beginning of the second grade shift. This was serious usage – besides large quantities of powder there are pieces of red pigment ground to crayon and pencil shapes either by or for use. Often pigment was brought to the site from distances of up to 25 km away (Bordes 1952). From 250,000-year-old levels at Bečov in Czechoslovakia come pieces of ochre with parallel striations reflecting use, and quartzite grinding stones stained with pigment (Bahn & Vertut 1988: 69-71). From the even older site of Terra Amata in Nice – 350 kya – there are 75 pieces of striated pigment with hues ranging from brown and yellow to red and purple (ibid).
From 125 kya, Neanderthals made systematic use of pigments. Of 103 blocks of magnesium dioxide found at Peche de l’Azé, 67 were rounded or polished to crayon shapes by rubbing on a soft surface such as leather or human skin. Quantities of red ochre also appear at Neanderthal burial sites, such as that at Le Moustier, sprinkled with powder, or another at Chappelle aux Saints, with ochre sprinkled around the head. By the Upper Palaeolithic, pigment use had reached industrial proportions – some French living floors were reddened to a depth of 20 cm, and of 100 known burials, over 25 have pigment.
Neanderthals also went in for other kinds of mark-making including geometric designs. Even from pre-Neanderthal times there are cup marks, random dots, and pendant and churinga designs engraved in rock. There are also zigzags, parallel lines and, according to Marshack, ‘symbolic female figures’.
Figure 11 shows two examples of engraved bones from La Ferrasie in France and Bacho Kiro in Bulgaria. A late Mousterian limestone slab from Tsonskaia Cave in the Caucasus has an engraved cross, and a fossil mummulite (Figure 12) has another cross, formed from a natural crack across which a Neanderthal ‘artist’ has engraved a second line at right angles. From the same site – Tata in Hungary – comes a piece of elephant molar ivory, painted red on one surface, and with one edge polished from much handling. This is generally interpreted as a palette for mixing paint. Apparently, some Neanderthals took their mark-making seriously.
A striking feature of the Mousterian period is that we find a relatively high number of fairly complete Neanderthal fossils. Before 125 kya even partly complete hominids are extremely rare, for the simple reason that any carcase lying on the ground will be eaten or torn apart by scavengers. So this is evidence that Neanderthals buried their dead.
Now archaeologists tend towards one of two positions. There are romantics who project ‘symbolic behaviour’ into the remote past, believing, for example, that Homo habilis could speak. Then there are kill-joys who deny anything ‘symbolic’ before the Upper Palaeolithic revolution around 40 kya. So romantics see Neanderthal burials as evidence of ritual and religious belief. Kill-joys say No, they were crushed by roof falls or crawled into caves to die. But then we might ask why we find no crushed hominids in South Africa, or crushed cave bears or hyenas anywhere.
Sceptics insist that intentional burial can only be inferred if there are grave goods or other evidence of ritual. Romantics then point to Neanderthals curled into a foetal position, surely indicating beliefs in rebirth and the after-life. No, say the sceptics, they crawled into a depression and curled up to die because they were cold or in pain. The classic case is the so-called ‘flower burial’ at Shanidar: a Neanderthal burial where the body was strewn with large quantities of pollen and anthers, apparently covered with flowers before burial. No, say the kill-joys, the workmen employed for the excavation tramped the pollen in on their boots. Similar controversies surround cases of alleged ‘bear ritual’, ‘ritual circles’ of stones, and apparent ‘grave goods’ such as antlers, jaw bones, and mammoth tusks. The opposing arguments are repeatedly ‘disproved’ by both sides.
There is little doubt that at least some Neanderthals were intentionally buried, but that does not indicate economico-moral ritual. Mourning involves primary intersubjectivity which we share with apes, elephants, and Congo grey parrots. Elephants treat elephant bones with respect – gently removing them from a forest path, for example. All that is required to explain Mousterian burials is the ability to live in caves, which requires fire to keep out other cave-dwelling animals. Neanderthals stacked the bones of the animals they ate in cavities or at the backs of caves, and they would be no less tidy with the bodies of their own dead. So-called ‘grave goods’ could be spontaneous expressions of grief, or continuous with giving and sharing behaviour that would be extended to the deceased during life.
The third grade shift
Romantics see all this ‘symbolic behaviour’ as anticipating the Upper Palaeolithic revolution. There is no dispute concerning the modern character of Upper Palaeolithic culture, associated with the arrival of modern humans in Europe from Africa. The transition from the Middle to the Upper Palaeolithic is distinctly sudden in geological terms, and the changes are dramatic. For the first time we see prolific representational art in durable materials – including imaginary beings such as the lion-headed man from Hohlenstein-Stadel in Germany (Bahn & Vertut 1988). We find the first musical instruments, revolutionary new tools including many made from bone and ivory, vast exchange networks spanning the whole of Europe and western Asia, and systematic ritual burials with lavish sumptuary goods. Further, the pace of change accelerates abruptly. Whereas the Acheulian lasted for over a million years, and even the Mousterian almost 100,000, new traditions come and go at intervals of a mere 5,000 years – Aurignacian, Gravettian, Solutrian, Magdalenian, etc.
What is debated is just how sudden the change really was, and whether it was brought from Africa by modern human immigrants, or whether it was an indigenous development, possibly even originating with Neanderthals. There is certainly no such dramatic change in Africa. Part of the problem is that, in Africa, many sites were abandoned due to hyper-aridity during the critical period, 60-30 kya. Further, the transition from the Middle to the Later Stone Age in many parts of Africa did not happen until 25-20 kya, and some Africans even today – such as the Koi-San in the Kalahari – still have a Middle Stone Age material culture. Nevertheless they have modern culture – so the Late Stone Age cannot represent the beginning of ritual and economico-moral culture.
There are many differences between African and Eurasian archaeology. In Eurasia, the Upper Palaeolithic is associated with the arrival of modern humans, whereas in Africa modern humans evolved, and were anatomically modern at least 100,000 years ago, well before the Later Stone Age.
The Middle Stone Age (MSA) in Africa is likewise very different from the Middle Palaeolithic (MP) in Europe. Whereas the Mousterian/MP is coextensive with Neanderthals and remained essentially unchanged for 100,000 years, the African MSA is associated with gradual anatomical change and several technological changes. There were very few of the display objects – pendants, engraved bones, etc – and burials, such as those associated with Neanderthals. This may simply reflect relatively less research in Africa, or a greater use of body paint in Africa for self-adornment, since the African climate does not generally require clothing.
What is more remarkable is the curious appearance and disappearance of modern-looking technologies in disparate locations – the Mugharan in the Near East, the Aterian in North Africa, and the Howiesons Poort in South Africa. Coinciding with the first Wurm glaciation, from around 80 kya, modern looking technologies appear – in the case of the Mugharan out of a previously Acheulian culture, and elsewhere in more typically MSA contexts. Then they are replaced by further MSA assemblages. At the Mugharan site of Hua Fteah there was even an uncompleted bone flute dating to 50 kya.
It would seem that modern culture originated in Africa before 100 kya, and was brought to these outlying areas by Ice Age migrations. In South Africa, there was a tenfold increase in red ochre usage around 110 kya, suggesting the origin of ritually-based culture at or before that date (Watts 1999). Genetic research indicates a population bottle-neck also around 100 kya, with all modern humans descended from a small African population with no more than 500 females of reproductive age (Harpending et al. 1993). Chronological language studies likewise suggest a single ancestral language originating in Africa somewhere between 200 kya and 50 kya (language studies cannot be more definite because there is no reliable ‘genetic clock’ for language) (Donald 1991; Noble & Davidson 1996).
Whereas in Eurasia we see a single immigrant population, possibly speaking a common language, with a single culture extending uniformly over a vast area, in Africa we see a cultural mosaic. This difference suggests diasporic spread in Eurasia, as opposed to acculturational spread in Africa, with other modern human groups copying the new culture from its originators.
Conclusion
I have argued that a ‘play and display’ hypothesis of human brain expansion makes more sense of the available evidence than cognocentric and logocentric hypotheses. According to this hypothesis human brain expansion was driven by social display, and self-awareness evolved in parallel with social display. There were three major grade shifts in this process. Song-and-dance display drove the first phase of brain expansion between 2.5 and 2 mya, associated with greatly increased implicit self-awareness, social insight, cooperation, and trust. Sometime within the last half million years modern levels of pretend play evolved, along with further elaboration of song-and-dance display, associated with a second phase of brain expansion, and increasing insight into epistemological mental states (theory of mind) and perception of the self in terms of social value. Neanderthals had less time for pretend play and may have lacked ‘theatre of mind’ (the ability to run social scenarios in imagination). The origin of ritual culture before 100 kya generated moral self-awareness and economico-moral personae, associated with a decline in brain size.
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