Menstruation was a key biological signal triggering the emergence of symbolic culture among early modern humans.
This theory has been particularly advocated by Darwinian anthropologists Chris Knight, Camilla Power and Ian Watts.
Introduction
The human female menstruates considerably more copiously than any other primate. As ovulation in the human female became concealed during the course of evolution (Alexander and Noonan 1979; Hrdy 2000), menstruation acquired new significance as a salient source of information about female fertility. Some have argued that for this reason, during the evolution of genus Homo, menstruation became a key sexual signal (Power and Aiello 1997). The argument is that because it ran counter to ovulation concealment - divulging instead of concealing important information about female fertility - menstruation in the pre-cultural past would have posed serious threats in terms of sexual conflict and competition. As a result, with the emergence of symbolic culture in Homo sapiens, it inevitably became hedged with restrictions and taboos (Knight, Power and Watts 1995).
Sexual signals and fertility
What role was played by menstruation in the origins of symbolic culture? Not all palaeoanthropologists would posit any significant connection. But Darwinians necessarily do relate these topics: menstruation carries important information about reproductive status. Knight, Power and Watts argue that during the course of evolution, ovulation in the human female became effectively concealed, leaving menstruation especially salient as a source of information about female fertility. Why conceal ovulation? While there are many different theories (Hrdy 2000), one obvious benefit to females is that it withholds information that would allow male philanderers to ‘hit and run’ – to identify females at their fertile moment, make them pregnant and then abandon them in favour of their next target. In this light, it has been argued that by scrambling the signal of fertility, ancestral Homo females in effect compelled the male to spend more time and energy hanging around with the current partner if he was to have a chance of getting her pregnant (Alexander and Noonan 1979). As offspring in Homo lineage became increasingly large brained, slow maturing and heavily dependent, their mothers needed provisioning and other forms of investment from their male partners, rather than requiring only sperm (which is the situation in chimpanzees). Withholding information about fertility was arguably a mechanism by which females could make male investment a condition of sexual access, ensuring support for offspring.
Why menstruation matters to males
But menstruation gives the game away as far as information about female fertility is concerned. A would-be male philanderer can easily tell the difference, in terms of fertility prospects, between a heavily pregnant female, a nursing female or one who is currently menstruating. The danger was that by monitoring who was or wasn’t menstruating, philanderer males might target females known to be cycling, regardless of the costs to their abandoned – pregnant and breast-feeding – former partners. Non-human primate females need not worry about such matters: males are not much use to anyone apart from their sperm, and mothers are generally well able to provision their offspring all by themselves. But humans are different. In view of the extremely heavy burdens of motherhood in the case of our species, we would not expect any human female to welcome being impregnated by a male who subsequently abandons her in order to impregnate someone else. Such considerations may help explain the extraordinary attention focused upon menstruation in virtually all hunter-gatherer and other traditional cultures (Knight 1991, 1996).
Female counter-strategies
The females most immediately threatened by the costs of male philandering are those who are pregnant or lactating, and who are therefore most in need of additional energy and resources. Darwinian anthropologists would expect the females most at risk to mount counter-strategies to prevent male investment from being siphoned off by visibly cycling (i.e. imminently fertile) sexual rivals (Knight, Power and Watts 1995; Power and Aiello 1997). The coalition of non-cycling females needs to grab any female who is menstruating, preventing philanderer males from taking her away. There are essentially two possibilities open to them. One is that non- cycling females try to hide the cycling ones. The reason this isn’t such a good idea is that the promise of imminent fertility is very interesting to males. From a Darwinian perspective, no male can afford to ignore such information. Therefore, advertising menstruation has economic value: it can be used to motivate males to work for prospectively fertile sex. The alternative to concealment is to take collective control of the signal, amplify it and broadcast it to all males in the vicinity. Hunter-gatherer rituals celebrating a young woman's first menstruation can be understood in terms of this strategy. Typically, the 'New Maiden' (as she is called in the Kalahari) is depicted as inseparably bound up with her aunts, sisters and other kinswomen, who carefully control sexual access to her (Lewis-Williams 1981). One way to prevent philanderer males from picking and choosing between females on the basis of their biological signals is to use cosmetics. Ethnographically, brilliant red cosmetics (body paint) are particularly associated with hunter-gatherer first menstruation rituals, not only in sub-Saharan Africa but cross- culturally (Knight 1991; Watts 1999; Power 1999). Superficially, rituals of this kind may appear oppressive and coercive. From a Western perspective, we might ask: 'Why not let the girl have a good time?' But a young woman who got pregnant and was abandoned with with her baby might face special hardships as a mother. By grabbing hold of her from the outset and controlling her movements, her aunts and other female kin offer her the security of an insurance society or childcare co-operative. Although commitment to such a body may entail privations in the short term, in the longer-term each new entrant has everything to gain. In fact (according to proponents of this model), rituals of this kind - known as 'initiation rites' - are one of the prime mechanisms by which hunter- gatherer women maintain their sexual solidarity and bargaining power, this in turn serving to uphold the political and social egalitarianism so characteristic of most hunter-gatherer populations.
The world's first ritual
The 'Female Cosmetic Coalitions’ theory (Knight 1999) offers a prototype for the world’s first initiation rite, and therefore for the intergenerational transmission of earliest human morality, kinship, ritual, cosmology and religion – in short, for ‘the rule of law’. The claim is that we now have a system of cultural replication, over and above genetic replication. In other words, we have the origins of symbolic culture itself.
This model is new and controversial. Its proponents argue that it is at least testable and can be proved wrong. How might it be proved wrong? If the first evidence for human ritual activity in the archaeological record is not a cosmetics industry focused on red pigment, then the theory is wrong. Even if the first evidence were red ochre, but it first appeared outside a time-window roughly 500,000 - 150,000 BP (before present), then the theory is wrong. It is interesting, therefore, to review the global archaeological record of mineral pigments, including iron oxides (ochre and haematite) (Watts 1999). The main picture reveals a record of some use of red pigments in Central Africa and southern Africa with a time-depth of 300,000 years (Barham 2002), followed by an explosion of red ochre mining and cosmetics manufacture from over 100,000 years ago, coinciding with the origins of our species (Watts 1999).
The emergence of morality and kinship
How does this model work in terms of morality and kinship? According to its proponents, the onset of menstruation prompts females on a periodic basis to form coalitions that include their sons and brothers, the aim being to deter outsider males from attempting primate-style sexual dominance and associated philandering (Knight 1999). In effect, coalitions of kin-related males and females begin signaling to outsider males: ‘You can have sex with our womenfolk, but only on our terms!’. Anybody might naturally object that sexually motivated males can always use violence to get their way. But violence entails certain risks and costs. If these can be sufficiently raised – in other words, if sufficient resistance can be mounted – males might be persuaded to try another way. The argument is that this ‘other way’ resulted in the establishment of group-level social cooperation based on collective moral norms. If we think in terms of the costs and benefits to outsider males, what have they got to lose? By giving in gracefully, they get to go hunting, bring back meat, have lots of sex, win respect and status – and help their own offspring survive.
Testing the model
Predictions
How might we expect females (backed by their male kin) to signal their sexual resistance? At this point, proponents of the theory take the signals normal in primate sexual soliciting and simply reverse them (Knight, Power and Watts 1995). A female chimpanzee in oestrus courts male attention using body-language which signals, in effect, ‘I am the right species, the right sex and this is the right time’. The reverse of this would be a display of all-female resistance. To indicate ritually 'taboo' or 'sacred' status, females should deploy body language indicating: ‘We are the wrong species, the wrong sex and this is the wrong time!’. This is a purely logical, abstract argument, but its advantage is that it allows anthropologists, rock art specialists and others with relevant data to test the whole theory (Knight 1997, Power and Watts 1997, Power 2004). The question, in this context, is what does ‘God’ look like in the first place? If the theory is correct, we should expect ambivalence of sex, species and time. If any rock-art specialist were to discover an image of supernatural potency which violated these specifications, the theory would be disproved. Imagery depicting a divine or supernatural couple with offspring or engaged in marital sex, for example, would disprove the theory.
Evidence from myth and ritual
Turning, now, to the evidence from world mythology, proponents of the model point to a rich store of relevant data (Knight 1997; Power and Watts 1997; Watts 2005). In the third volume of Mythologiques, the anthropologist Claude Lévi-Strauss (1978) focuses heavily on lunar and menstrual periodicity. In world mythology, the core motif of death and rebirth is central to the experience of initiation; recurrently, this experience is linked symbolically with the moon's death and rebirth. Lévi-Strauss concludes that the myths of humanity can be conceptualised ultimately as so many different versions of a single myth. European fairy tales centre on the motif of death and rebirth; these too - if Lévi-Strauss is correct - may be seen as variations on the same basic theme. In the well-known story collected by the Brothers Grimm, The Sleeping Beauty depicts the spell-casting potency of a royal menstrual flow, in this case coded as Beauty’s pricking of her finger and consequent sleep for one hundred years.
As women come under the monthly spell, world mythology places the moon, too, in its dark, secluded phase (Watts 2005). Among the Amazonian Barasana, ‘mythology says the moon copulates with menstruating women and that during an eclipse of the moon, called the ‘dying moon’, the moon becomes a small red ball of menstrual blood which comes to earth and fills the house and its objects’ (Hugh-Jones 1979). Such is the ritual potency of menstruation that over much of Aboriginal Australia, men underwent a painful genital operation known as subincision in order to bleed together on ritual occasions (Montagu 1974). Working on an island in Papua New Guinea, one social anthropologist entitled his ethnography The Island of Menstruating Men (Hogbin 1970). Counterparts in other parts of the world abound. Where bleeding is central to male rites of initiation, myths typically attribute the technique to a culture-hero who used trickery or violence to steal the secret from women.
Khoisan women in the Kalahari are ritually most powerful when menstruating. A girl in seclusion is metaphorically a bleeding, wounded game animal (‘wrong species, wrong sex, wrong time’); in her special hut, the 'New Maiden' is thought to be inviolable – having only to snap her fingers to bring down lightning on any disrespectful male (Lewis-Williams 1981; Power and Watts 1997). While the girl is secluded, other women dance around her, acting as if they are rutting antelopes. This ‘Eland Bull Dance’ spurs men to success in the hunt.
Ritual taboos surrounding menstruation are not necessarily expressions of male sexual dominance (Buckley and Gottlieb 1988). Current evolutionary models suggest that joyful dances like those of the Kalahari Bushmen may once have empowered women by structuring the first sexual division of labour. Instead of gaining meat by chasing after male hunters, in this view, earliest culturally organized women stood their own ground, forming semi-permanent home bases in which to care for their heavily dependent offspring. One strategy for obtaining meat was to refuse sex until the men had brought home their kills, using their blood to signal solidarity and defiance.
References
Alexander, R. D. and K. M. Noonan 1979. 'Concealment of ovulation, parental care, and human social evolution.' In N. Chagnon and W. Irons (eds), Evolutionary Biology and Human Social Behavior. North Scituate, MA: Duxbury Press, pp. 436-453.
Barham, L. S. 2002. 'Systematic pigment use in the Middle Pleistocene of South-Central Africa.' Current Anthropology 43 (1): 181-190.
Buckley, T. and A. Gottlieb (eds), 1988. Blood Magic. The anthropology of menstruation. Berkeley: University of California Press.
Hogbin, I. A. 1970. The Island of Menstruating Men. Scranton, London and Toronto: Chandler. Hrdy, S. B. 2000. Mother Nature. London: Vintage.
Hugh-Jones, C. 1979. From the Milk River. Spatial and temporal processes in northwest Amazonia. Cambridge: Cambridge University Press.
Knight, C. 1991. Blood Relations. Menstruation and the origins of culture. New Haven and London: Yale University Press.
Knight, C. 1996. 'Menstruation'. In A. Barnard and J. Spencer (eds), "Encyclopedia of Social and Cultural Anthropology". Routledge: London & New York, pp. 363-4.
Knight, C. 1997. 'The wives of the sun and moon.' Journal of the Royal Anthropological Institute 3(N.S.): 133-153.
Knight, C. 1999. 'Sex and language as pretend-play'. In R. Dunbar, C. Knight and C. Power (eds), The Evolution of Culture. Edinburgh: Edinburgh University Press, pp. 228-47.
Knight, C., C. Power and I. Watts 1995. 'The human symbolic revolution: A Darwinian account.' Cambridge Archaeological Journal. 5(1): 75-114.
Lévi-Strauss, C. 1978. The Origin of Table Manners. Introduction to a Science of Mythology 3. London: Cape.
Lewis-Williams, J. D. 1981. Believing and Seeing. Symbolic meanings in Southern San rock paintings. London: Academic Press.
Montagu, M. F. A. 1974. Coming into Being Among the Australian Aborigines. The procreative beliefs of the Australian Aborigines. London and Boston: Routledge and Kegan Paul.
Power, C. 2004. 'Women in prehistoric art.' In G. Berghaus (ed.) New Perspectives on Prehistoric Art. Praeger: Westport, CT/London, pp.75-103.
Power, C. and L. C. Aiello 1997. 'Female proto-symbolic strategies.' In L. D. Hager (ed.), Women in Human Evolution. New York and London: Routledge, pp. 153-171.
Power, C. and I. Watts 1997. 'The woman with the zebra's penis. Gender, mutability and performance.' Journal of the Royal Anthropological Institute 3(N.S.): 537-560.
Watts, I. 1999. The origin of symbolic culture. In R. Dunbar, C. Knight and C. Power (eds), The Evolution of Culture. Edinburgh: Edinburgh University Press, pp. 113-146.
Watts, I. 2005. ‘Time, too, grows on the Moon’: Some evidence for Knight’s theory of a human universal. In W. James & D. Mills (eds), The Qualities of Time: Anthropological Approaches. New York: Berg, pp. 95-118.
This theory has been particularly advocated by Darwinian anthropologists Chris Knight, Camilla Power and Ian Watts.
Introduction
The human female menstruates considerably more copiously than any other primate. As ovulation in the human female became concealed during the course of evolution (Alexander and Noonan 1979; Hrdy 2000), menstruation acquired new significance as a salient source of information about female fertility. Some have argued that for this reason, during the evolution of genus Homo, menstruation became a key sexual signal (Power and Aiello 1997). The argument is that because it ran counter to ovulation concealment - divulging instead of concealing important information about female fertility - menstruation in the pre-cultural past would have posed serious threats in terms of sexual conflict and competition. As a result, with the emergence of symbolic culture in Homo sapiens, it inevitably became hedged with restrictions and taboos (Knight, Power and Watts 1995).
Sexual signals and fertility
What role was played by menstruation in the origins of symbolic culture? Not all palaeoanthropologists would posit any significant connection. But Darwinians necessarily do relate these topics: menstruation carries important information about reproductive status. Knight, Power and Watts argue that during the course of evolution, ovulation in the human female became effectively concealed, leaving menstruation especially salient as a source of information about female fertility. Why conceal ovulation? While there are many different theories (Hrdy 2000), one obvious benefit to females is that it withholds information that would allow male philanderers to ‘hit and run’ – to identify females at their fertile moment, make them pregnant and then abandon them in favour of their next target. In this light, it has been argued that by scrambling the signal of fertility, ancestral Homo females in effect compelled the male to spend more time and energy hanging around with the current partner if he was to have a chance of getting her pregnant (Alexander and Noonan 1979). As offspring in Homo lineage became increasingly large brained, slow maturing and heavily dependent, their mothers needed provisioning and other forms of investment from their male partners, rather than requiring only sperm (which is the situation in chimpanzees). Withholding information about fertility was arguably a mechanism by which females could make male investment a condition of sexual access, ensuring support for offspring.
Why menstruation matters to males
But menstruation gives the game away as far as information about female fertility is concerned. A would-be male philanderer can easily tell the difference, in terms of fertility prospects, between a heavily pregnant female, a nursing female or one who is currently menstruating. The danger was that by monitoring who was or wasn’t menstruating, philanderer males might target females known to be cycling, regardless of the costs to their abandoned – pregnant and breast-feeding – former partners. Non-human primate females need not worry about such matters: males are not much use to anyone apart from their sperm, and mothers are generally well able to provision their offspring all by themselves. But humans are different. In view of the extremely heavy burdens of motherhood in the case of our species, we would not expect any human female to welcome being impregnated by a male who subsequently abandons her in order to impregnate someone else. Such considerations may help explain the extraordinary attention focused upon menstruation in virtually all hunter-gatherer and other traditional cultures (Knight 1991, 1996).
Female counter-strategies
The females most immediately threatened by the costs of male philandering are those who are pregnant or lactating, and who are therefore most in need of additional energy and resources. Darwinian anthropologists would expect the females most at risk to mount counter-strategies to prevent male investment from being siphoned off by visibly cycling (i.e. imminently fertile) sexual rivals (Knight, Power and Watts 1995; Power and Aiello 1997). The coalition of non-cycling females needs to grab any female who is menstruating, preventing philanderer males from taking her away. There are essentially two possibilities open to them. One is that non- cycling females try to hide the cycling ones. The reason this isn’t such a good idea is that the promise of imminent fertility is very interesting to males. From a Darwinian perspective, no male can afford to ignore such information. Therefore, advertising menstruation has economic value: it can be used to motivate males to work for prospectively fertile sex. The alternative to concealment is to take collective control of the signal, amplify it and broadcast it to all males in the vicinity. Hunter-gatherer rituals celebrating a young woman's first menstruation can be understood in terms of this strategy. Typically, the 'New Maiden' (as she is called in the Kalahari) is depicted as inseparably bound up with her aunts, sisters and other kinswomen, who carefully control sexual access to her (Lewis-Williams 1981). One way to prevent philanderer males from picking and choosing between females on the basis of their biological signals is to use cosmetics. Ethnographically, brilliant red cosmetics (body paint) are particularly associated with hunter-gatherer first menstruation rituals, not only in sub-Saharan Africa but cross- culturally (Knight 1991; Watts 1999; Power 1999). Superficially, rituals of this kind may appear oppressive and coercive. From a Western perspective, we might ask: 'Why not let the girl have a good time?' But a young woman who got pregnant and was abandoned with with her baby might face special hardships as a mother. By grabbing hold of her from the outset and controlling her movements, her aunts and other female kin offer her the security of an insurance society or childcare co-operative. Although commitment to such a body may entail privations in the short term, in the longer-term each new entrant has everything to gain. In fact (according to proponents of this model), rituals of this kind - known as 'initiation rites' - are one of the prime mechanisms by which hunter- gatherer women maintain their sexual solidarity and bargaining power, this in turn serving to uphold the political and social egalitarianism so characteristic of most hunter-gatherer populations.
The world's first ritual
The 'Female Cosmetic Coalitions’ theory (Knight 1999) offers a prototype for the world’s first initiation rite, and therefore for the intergenerational transmission of earliest human morality, kinship, ritual, cosmology and religion – in short, for ‘the rule of law’. The claim is that we now have a system of cultural replication, over and above genetic replication. In other words, we have the origins of symbolic culture itself.
This model is new and controversial. Its proponents argue that it is at least testable and can be proved wrong. How might it be proved wrong? If the first evidence for human ritual activity in the archaeological record is not a cosmetics industry focused on red pigment, then the theory is wrong. Even if the first evidence were red ochre, but it first appeared outside a time-window roughly 500,000 - 150,000 BP (before present), then the theory is wrong. It is interesting, therefore, to review the global archaeological record of mineral pigments, including iron oxides (ochre and haematite) (Watts 1999). The main picture reveals a record of some use of red pigments in Central Africa and southern Africa with a time-depth of 300,000 years (Barham 2002), followed by an explosion of red ochre mining and cosmetics manufacture from over 100,000 years ago, coinciding with the origins of our species (Watts 1999).
The emergence of morality and kinship
How does this model work in terms of morality and kinship? According to its proponents, the onset of menstruation prompts females on a periodic basis to form coalitions that include their sons and brothers, the aim being to deter outsider males from attempting primate-style sexual dominance and associated philandering (Knight 1999). In effect, coalitions of kin-related males and females begin signaling to outsider males: ‘You can have sex with our womenfolk, but only on our terms!’. Anybody might naturally object that sexually motivated males can always use violence to get their way. But violence entails certain risks and costs. If these can be sufficiently raised – in other words, if sufficient resistance can be mounted – males might be persuaded to try another way. The argument is that this ‘other way’ resulted in the establishment of group-level social cooperation based on collective moral norms. If we think in terms of the costs and benefits to outsider males, what have they got to lose? By giving in gracefully, they get to go hunting, bring back meat, have lots of sex, win respect and status – and help their own offspring survive.
Testing the model
Predictions
How might we expect females (backed by their male kin) to signal their sexual resistance? At this point, proponents of the theory take the signals normal in primate sexual soliciting and simply reverse them (Knight, Power and Watts 1995). A female chimpanzee in oestrus courts male attention using body-language which signals, in effect, ‘I am the right species, the right sex and this is the right time’. The reverse of this would be a display of all-female resistance. To indicate ritually 'taboo' or 'sacred' status, females should deploy body language indicating: ‘We are the wrong species, the wrong sex and this is the wrong time!’. This is a purely logical, abstract argument, but its advantage is that it allows anthropologists, rock art specialists and others with relevant data to test the whole theory (Knight 1997, Power and Watts 1997, Power 2004). The question, in this context, is what does ‘God’ look like in the first place? If the theory is correct, we should expect ambivalence of sex, species and time. If any rock-art specialist were to discover an image of supernatural potency which violated these specifications, the theory would be disproved. Imagery depicting a divine or supernatural couple with offspring or engaged in marital sex, for example, would disprove the theory.
Evidence from myth and ritual
Turning, now, to the evidence from world mythology, proponents of the model point to a rich store of relevant data (Knight 1997; Power and Watts 1997; Watts 2005). In the third volume of Mythologiques, the anthropologist Claude Lévi-Strauss (1978) focuses heavily on lunar and menstrual periodicity. In world mythology, the core motif of death and rebirth is central to the experience of initiation; recurrently, this experience is linked symbolically with the moon's death and rebirth. Lévi-Strauss concludes that the myths of humanity can be conceptualised ultimately as so many different versions of a single myth. European fairy tales centre on the motif of death and rebirth; these too - if Lévi-Strauss is correct - may be seen as variations on the same basic theme. In the well-known story collected by the Brothers Grimm, The Sleeping Beauty depicts the spell-casting potency of a royal menstrual flow, in this case coded as Beauty’s pricking of her finger and consequent sleep for one hundred years.
As women come under the monthly spell, world mythology places the moon, too, in its dark, secluded phase (Watts 2005). Among the Amazonian Barasana, ‘mythology says the moon copulates with menstruating women and that during an eclipse of the moon, called the ‘dying moon’, the moon becomes a small red ball of menstrual blood which comes to earth and fills the house and its objects’ (Hugh-Jones 1979). Such is the ritual potency of menstruation that over much of Aboriginal Australia, men underwent a painful genital operation known as subincision in order to bleed together on ritual occasions (Montagu 1974). Working on an island in Papua New Guinea, one social anthropologist entitled his ethnography The Island of Menstruating Men (Hogbin 1970). Counterparts in other parts of the world abound. Where bleeding is central to male rites of initiation, myths typically attribute the technique to a culture-hero who used trickery or violence to steal the secret from women.
Khoisan women in the Kalahari are ritually most powerful when menstruating. A girl in seclusion is metaphorically a bleeding, wounded game animal (‘wrong species, wrong sex, wrong time’); in her special hut, the 'New Maiden' is thought to be inviolable – having only to snap her fingers to bring down lightning on any disrespectful male (Lewis-Williams 1981; Power and Watts 1997). While the girl is secluded, other women dance around her, acting as if they are rutting antelopes. This ‘Eland Bull Dance’ spurs men to success in the hunt.
Ritual taboos surrounding menstruation are not necessarily expressions of male sexual dominance (Buckley and Gottlieb 1988). Current evolutionary models suggest that joyful dances like those of the Kalahari Bushmen may once have empowered women by structuring the first sexual division of labour. Instead of gaining meat by chasing after male hunters, in this view, earliest culturally organized women stood their own ground, forming semi-permanent home bases in which to care for their heavily dependent offspring. One strategy for obtaining meat was to refuse sex until the men had brought home their kills, using their blood to signal solidarity and defiance.
References
Alexander, R. D. and K. M. Noonan 1979. 'Concealment of ovulation, parental care, and human social evolution.' In N. Chagnon and W. Irons (eds), Evolutionary Biology and Human Social Behavior. North Scituate, MA: Duxbury Press, pp. 436-453.
Barham, L. S. 2002. 'Systematic pigment use in the Middle Pleistocene of South-Central Africa.' Current Anthropology 43 (1): 181-190.
Buckley, T. and A. Gottlieb (eds), 1988. Blood Magic. The anthropology of menstruation. Berkeley: University of California Press.
Hogbin, I. A. 1970. The Island of Menstruating Men. Scranton, London and Toronto: Chandler. Hrdy, S. B. 2000. Mother Nature. London: Vintage.
Hugh-Jones, C. 1979. From the Milk River. Spatial and temporal processes in northwest Amazonia. Cambridge: Cambridge University Press.
Knight, C. 1991. Blood Relations. Menstruation and the origins of culture. New Haven and London: Yale University Press.
Knight, C. 1996. 'Menstruation'. In A. Barnard and J. Spencer (eds), "Encyclopedia of Social and Cultural Anthropology". Routledge: London & New York, pp. 363-4.
Knight, C. 1997. 'The wives of the sun and moon.' Journal of the Royal Anthropological Institute 3(N.S.): 133-153.
Knight, C. 1999. 'Sex and language as pretend-play'. In R. Dunbar, C. Knight and C. Power (eds), The Evolution of Culture. Edinburgh: Edinburgh University Press, pp. 228-47.
Knight, C., C. Power and I. Watts 1995. 'The human symbolic revolution: A Darwinian account.' Cambridge Archaeological Journal. 5(1): 75-114.
Lévi-Strauss, C. 1978. The Origin of Table Manners. Introduction to a Science of Mythology 3. London: Cape.
Lewis-Williams, J. D. 1981. Believing and Seeing. Symbolic meanings in Southern San rock paintings. London: Academic Press.
Montagu, M. F. A. 1974. Coming into Being Among the Australian Aborigines. The procreative beliefs of the Australian Aborigines. London and Boston: Routledge and Kegan Paul.
Power, C. 2004. 'Women in prehistoric art.' In G. Berghaus (ed.) New Perspectives on Prehistoric Art. Praeger: Westport, CT/London, pp.75-103.
Power, C. and L. C. Aiello 1997. 'Female proto-symbolic strategies.' In L. D. Hager (ed.), Women in Human Evolution. New York and London: Routledge, pp. 153-171.
Power, C. and I. Watts 1997. 'The woman with the zebra's penis. Gender, mutability and performance.' Journal of the Royal Anthropological Institute 3(N.S.): 537-560.
Watts, I. 1999. The origin of symbolic culture. In R. Dunbar, C. Knight and C. Power (eds), The Evolution of Culture. Edinburgh: Edinburgh University Press, pp. 113-146.
Watts, I. 2005. ‘Time, too, grows on the Moon’: Some evidence for Knight’s theory of a human universal. In W. James & D. Mills (eds), The Qualities of Time: Anthropological Approaches. New York: Berg, pp. 95-118.