Early humans lived in bands or tribal societies and only gradually did more complex stratified societies evolve. In chiefdoms or states there is enough division of labour for some people to be completely freed from
food production; these are typically rulers of various kinds, together with soldiers and priests. Diamond (1997) argues that the function of ideologies and religions in chiefdoms is to justify the redistribution of wealth, the authority of the rulers, and warfare. Chiefs typically take enormous amounts of wealth from working people and use some of it to build grand temples or public works as visible signs of their power. The people may accept their wealth being taken from them, as they accept taxation in modern societies, if they obtain benefits in return. These benefits may include the reduction of violence within the society, protection from enemies, or facilities for public use. Sometimes the ruler and priest are the same person, but in larger societies separate priests take on the religious functions. The priests promote and police the religious beliefs; the beliefs are then used to justify the conquest of other peoples from whom more goods and power can be stolen.
In memetic terms what this amounts to is that the religious memes are more likely to survive and replicate than competing memes are. For example, religions that required no priests, that took no taxes, or that built no impressive buildings, would have been at a disadvantage. This meant the proliferation of highly organised and stratified societies and of priests who taught and maintained the religion. Religious memes have therefore played an important role in the development of human societies.
The coevolutionary question is whether they have affected the genes along the way. E. O. Wilson (1978) treated religions as a challenge to his new science of sociobiology and speculated about the ways in which religious belief could provide a genetic advantage. For example, religions often include prohibitions against eating potentially contaminated foods, and against incest and other risky sexual activities, and encourage believers to have large and well–protected families. In these and other ways religious belief would benefit the genes of believers and so be expected to continue. The evolutionary psychologist Steven Pinker (1997) has argued that religious beliefs are by–products of the brain modules that were designed to do other things; spirits and gods are based on our concepts of animals and people; supernatural powers are inferred from natural powers; the idea of other worlds is based on dreams and trances. As he puts it: ‘religious beliefs are notable for their lack of imagination (God is a jealous man; heaven and hell are places; souls are people who have sprouted wings)’ (Pinker 1997, p. 557). These authors argue either that religions provide a genetic advantage, or that they are the by–product of things that once provided genetic advantage. They do not consider the possibility of memetic advantage, nor of memes driving genes.
There are several ways in which memes might have influenced genes. Priests attain power and status by predicting (or appearing to predict) weather, disease, or crop failures; by building or being associated with temples and other grand buildings; by wearing expensive and impressive clothes; and by claiming supernatural powers. In many cultures the priests or rulers are given divine status. We know that women prefer to mate with high–status men, and that these men leave more offspring, either by having more wives or by fathering children by women who are not their wives. Even in societies in which the priesthood is celibate and could not (or at least should not) pass on their genes, other people could acquire power by association. If this religious behaviour helped people acquire more mates, then any genes that inclined them to be more religious in the first place would also flourish. In this way
genes
for religious behaviour would increase because of religious
memes.
The idea of ‘genes for religious behaviour’ is not at all implausible – all it means is genes that make people more inclined towards religious beliefs and behaviour. Brain development is under genetic control and it is known that some brains are more prone to religious belief and experience than others. For example, people with unstable temporal lobes are more likely to report mystical, psychic and religious experiences, and to believe in supernatural powers, than those with stable temporal lobes (Persinger 1983). Like many other psychological variables, religiosity is known to have a heritable component even today. For example, identical twins are more similar in religiosity than non–identical twins or siblings. In our past there may have been as much genetically controlled variation in religious behaviour as there is now, or even more. If so, two effects are possible. First, the memetic environment could have influenced whether genes for religious behaviour were positively selected or not (increasing or decreasing religious behaviour in general). Second, the religion of the time could have influenced the
kinds
of genes that survived (i.e. those that produced the kind of religious behaviour best suited to that religion). That would be memetic driving at work.
Group selection
There is another way in which religious memes might conceivably drive the genes: through group selection. The whole concept of group selection has had a troubled history and been beset by controversy. Earlier this century it was invoked to explain all kinds of behaviours that might conceivably benefit groups or societies, and biologists often appealed to
‘group adaptations’ or ‘the good of the species’ without any idea of possible mechanisms. Williams’s classic book
Adaptation and Natural Selection
(1966) pointed out the errors: for example, that selfish individuals could always infiltrate altruistic groups and thrive at their expense. Also groups have a slow lifecycle compared with individuals, and individuals can often move between groups. This means that individual adaptations will almost always predominate over adaptations for the group. Therefore, we should not look to group selection as a force that can make individuals sacrifice their own genetic interests ‘for the good of the group’.
Most biologists now consider that group selection is only a weak force in nature (Mark Ridley 1996). However, selection at the level of the group can sometimes occur. Dawkins’s distinction between the replicator and the vehicle is helpful here. In most of biology the replicator (the thing that gets copied) is the gene, while the vehicle is the whole organism. Whole organisms; that is individual cats, donkeys, orchids or cockroaches, live or die, and in the process either pass on their genes or not. All the genes in that vehicle share the same fate. In this (the most common) case selection is taking place at the level of the organism.
In some cases, however, whole groups of organisms live or die, and so all the genes in the group are killed off at once. If this occurs then the group is the vehicle and we can say that selection is happening at the level of the group. This applies, for example, to whole species that go extinct, or to isolated populations of animals, such as those on small islands, in which some groups survive and some do not. In these cases there is no conflict between individual and group selection (as there was in the argument about altruistic behaviour) but selection has acted at the level of the group.
Ridley (1996) concludes that group selection works only if migration rates are implausibly low and group extinction rates implausibly high. Another way of putting it is that group selection is favoured by mechanisms that reduce the differences in biological fitness
within
the groups and increase differences
between
groups, thus concentrating selection at the group level (D. S. Wilson and Sober 1994).
Memes may provide just this kind of mechanism. Indeed Boyd and Richerson (1990) have used mathematical models to show that group selection is particularly likely to occur when behavioural variation is culturally acquired, and that it can even occur with large groups and substantial rates of migration. The important point is that memes can have precisely the effect of decreasing within–group differences and increasing between–group differences.
Let us take dietary habits as an example. Suppose that one group of people eat shellfish as a major part of their diet and develop ways of cooking mussels or clams and getting them out of their shells, while another group of people hold a taboo against eating shellfish. People within each group are more similar to each other, and different from people in the other group. Migration between groups is made difficult by long habits of taste, and the difficulty of learning how to prepare the food. In some environments the first group may do better because they get more protein, while in other environments the second group may do better because they survive a lethal disease from infected food. When disease strikes or famine threatens it is whole groups that live or die. Food taboos are an important part of many religions. Orthodox Jews do not eat shellfish or pork and avoid mixing meat with milk. Many Buddhists and Hindus are vegetarians because they do not want to kill animals. The beliefs that underpinned these taboos may have caused some groups of people to survive and others to go extinct; and both their genes and their memes would have gone with them.
Religions also dictate sexual practices, promote certain kinds of cooperative behaviour, and regulate aggression and violence. Although many people believe that primitive tribes live an idyllic and peaceful existence, this myth (like so many in anthropology) has been exploded. The anthropologist Napoleon Chagnon (1992) lived for many years with the Yanomamo, who live in the Brazilian rain forest by hunting and growing food in temporary gardens. He describes a violent life in which war between villages is common and murders are revenged with more murders. Similar stories come from many parts of the world. In New Guinea, a group of nomads called the Fayu live in small family groups who only rarely meet other families because of the revenge murders that ensue when they do. Gatherings, for example to exchange brides, are fraught with danger. In many tribal societies murder is a leading cause of death (Diamond 1997). Although many people in modern cities believe that they face ever increasing risks of being killed they are in fact far safer than they would have been in a band or tribal society. The organisation that comes with government and religion therefore decreases these kinds of violence. However, it also provides the justification for large–scale wars.
The history of warfare is largely a history of people killing each other for religious reasons. Religions give people a motive, other than genetic self–interest, for sacrificing their lives for others – something that does not happen in band and tribal societies. Young men may believe that it is good to die for God, heroic to be killed in a religious war, or that they will
have a place reserved for them in heaven. A society in which brave young men are prepared to die for their beliefs is likely to win a war against a society in which they are more concerned about protecting themselves or avenging their family. Such a victory is a victory for the memes that created the difference in the first place, and for the genes of the survivors.
We can now see why group selection might be important in memetics. Religions are a good example of a mechanism that decreases within–group differences, while increasing between–group differences and rates of group extinction. In many religions conformity is encouraged, forbidden behaviours are punished, differences between believers and unbelievers are exaggerated, fear or hatred of people with other beliefs is nurtured, and migration to a different religion made difficult or impossible. Wars between religious groups are common and in our evolutionary history many groups have lived or died for their religion. All this makes it more likely that group selection has occurred. If there were genetic differences between the groups to start with, then the survival of some groups and extinction of others would have had effects on the gene pool. In this case we could say that the religious memes have driven the genes.
This is likely to be most interesting if, for example, there was some genetic reason why one group took up one religion while a different group took up a different religion. Let us imagine two neighbouring groups of early hominids in which, by chance, one group had more of a genetic tendency to want to bury their dead in elaborate ways. This is not at all far–fetched if you remember that digging and burying behaviour is under genetic control in many species, from worms and wasps to rabbits and dogs. This genetic propensity then encouraged these people to develop a religion based on ancestor worship and an afterlife – we can call them the ‘Afterlifers’. Meanwhile, the other group developed a religion based on worshipping nature spirits – we can call them the ‘Naturists’. The Afterlifers then developed a taste for war, believing their ancestors’ spirits would aid them, and that they would individually go to heaven if they killed an enemy, whereas the Naturists just got on with their own interests. In consequence, the Afterlifers won more of the wars against the Naturists; their memes spread – and so did their genes. Genes for the original ritual burying behaviour were selected for by group selection driven by memes.
I am not suggesting that this precise series of events has actually happened, but that this general mechanism could have shaped human nature and given us our religious tendencies. The principle is a general one and could theoretically apply to all kinds of genetic predispositions,
such as conformity, having religious experiences, enjoying ritual and worship, or believing in life after death. This process could even have acted to favour genes that would otherwise be detrimental to fitness, or to wipe out genes that would otherwise have been fitness–enhancing. So some aspects of human nature could have been determined not for the sake of the genes but for the sake of the memes. Our beliefs could have moulded the way genetic selection took place. If this has happened it means that human beings might now be naturally religious creatures because of our long memetic history.
Religions have held enormous power for millennia, but times are changing and religions with them. One obvious change is that vertical transmission is giving way to the faster horizontal transmission (p. 132). As people are increasingly exposed to new ideas from television, radio, newspapers and the Internet, they begin to make comparisons and ask difficult questions. So it is, sadly, not surprising to learn that Afghanistan’s Taliban Islamic movement has forbidden televisions and radios, and has set about destroying any they find, and punishing their owners. Meanwhile, in countries with thriving communications, some of the tricks the old religions use may not work so well any more. When people can see films, go to art galleries, and listen to any music they like, the beauty trick is less effective. When we are subjected on television to the gruesome results of religious wars, the altruism trick wears thin. When Christian leaders argue over whether homosexuality is
really
a sin, the truth trick begins to weaken its grip.