How Evolution Changed Our Minds

American-born primatologist Alison Jolly, who sadly died on 6th February in Lewes, East Sussex, UK, was a Visiting Scientist at the University of Sussex and was instrumental in changing our view both about the role of social interaction in evolution and the role of gender in group leadership.

She was the first to report that females are dominant in some primate species, an observation based on her study of lemurs in Madagascar, where, unlike prosimians in the rest of the world, they have evolved in the absence of true monkeys to fill the niche occupied by true monkeys elsewhere. We now know that many primate groups are led by females, not males, so there is nothing inherently male about the ability to dominate and lead a group.

Her work also did much to change the then prevailing view that human intelligence evolved because of the need for more and more sophisticated tools, to the now generally accepted view that it was increasingly complex social interactions which was the main driver. Alison Jolly's research means we can sit back in quiet amusement when creationists display their occasional examples of critical thinking ability, knowing that even such a rarely-used ability only exists because it evolved in their monkey ancestors.

We now know that what underpins social interaction is not necessarily genetic at all but involves analogous replicators we now call memes or "memory genes" which form complexes which we inherit from our parents, peers and authority figures in our culture. As replicators they fulfil the three requirements for evolution:

• Inheritance.
• Imperfect replication.
• Selection.

This means they will inevitably and inexorably evolve over time towards perfection for their own perpetuation through time in that environments. Like all replicators, memes will tend to form alliances with other replicators, whether memetic of genetic, because the result of alliance is often greater fitness than a replicator acting in isolation. And so memes formed alliances with genes for bigger brains and brains capable of processing the necessary information. We now refer to this as gene-meme co-evolution which is especially, but not uniquely, relevant to human cultural, ethical and physical evolution.

Learning the rules of social interaction, deciding when and where to apply them and passing them on, all require intelligence and the ability to solve puzzles. As this ability increases so the rules can become more complex, limited seemingly only by the potential for evolving a larger brain with which to store and process this information.

It was only when early members of the Homo genus 'solved' the problem of how to grow a very large brain in comparison to that of other animals of equivalent body size, that we took off as a species both in our complex social evolution and in our tool making ability. As we adapted to an upright gait, which included reorganisation of the bones of our face to bring our eyes into a forward-looking position, this allowed our cranium to bulge upwards balanced on top of a spinal column instead of sticking out in front of it, so our brain was free to expand within the constraints imposed by the human female pelvis.

This increased brain size gave us such a huge advantage that it more than outweighed the resulting high mortality rate associated with pushing a large head through a curved birth canal; a rate far higher than in any other mammal. Our evolutionary partial response to this was to give birth to babies much earlier in their development and this paradoxically gave us a much longer period of childhood learning during which we could acquire these evolving memes and perfect our learned skill.

Alison Jolly's seminal paper published in Science in 1966 argued that the beginnings of human intelligence are to be found in early common ancestors in primates in which social interaction is an important part of daily life. In 1966 it was generally believed that man was the only tool-using animal so that could not have been the driver in our less intelligent relatives. We now know that we are far from alone in this skill and that several primates, and several unrelated species, also solve puzzles and fashion and use tools, but the general principle holds that most puzzle-solving primates are not toolmakers so tool making could not have driven their puzzle-solving ability.

Primates are extraordinary among mammals for their complex social relations and their ingenuity in handling (or destroying) objects. The evolutionary trends which led to the excellence of Homo sapiens in these lines began long before the transition from ape to man.

All monkey species are social. Although individuals may be solitary for a time, a monkey is usually part of a group throughout his life. And when he is taken from his wild group and loosed in laboratory or house he unlatches doors, solves hardware puzzles, and carefully stuffs aquariums with brass lamps and shredded medical texts. He can even be trained to drive tractors, or show the rudiments of symbolic thought...

An infant monkey, unlike an infant tiger or beaver or gnu, is likely to remain for life in the troop of its birth. The result is a social group of all ages, with several adults of either sex. When too large the group divides into smaller troops of roughly similar composition. This sort of social structure is rare in nonprimate mammals, but about half the primate genera studied conform to the rule...

Monkeys, more than any other mammals except their descendants, the apes and men, learn to be social. A rhesus raised in isolation from its kind may not mate normally or rear its own young. Primates have a long youth, compared to mammals of their size, and during this period, through association, exploration and play, the juveniles learn the ways of the troop. It is even possible that primates exploit the full capacity of their brain only during youth. Man, after all, accomplishes the gigantic feat of learning to speak, and may never again face such a daunting intellectual task...

In summary, the social use of intelligence is of crucial importance to all social primates. As the young develop, they depend on the troop for protection and for instruction in their role in life. Since their dependence on the troop both demands social earning and makes it possible, social integration and intelligence probably evolved together, reinforcing each other in an ever-increasing spiral. And, although it is very likely that the learned social relations of monkeys are in fact more complex than those of lemurs, our present techniques of description emphasize the similarity between lemur and monkey social interactions...

Primate society, thus, could develop without the object-learning capacity or manipulative ingenuity of monkeys. This manipulative, object cleverness, however, evolved only in the context of primate social life. Therefore, I would argue that some social life preceded, and determined the nature of, primate intelligence.

Summary and Conclusion.

Our human intellect has resulted from an enormous leap in capacity above the level of monkeys and apes. Earlier, though, Old and New World monkeys' intelligence outdistanced that of other mammals, including the prosimian primates. This first great advance in intelligence probably was selected through interspecific competition on the large continents. However, even at this early stage, primate social life provided the evolutionary context of primate intelligence...

Alison Jolly; Lemur Social Behavior and Primate Intelligence; Science, 29 July 1966, p. 501

These are the sorts of scientific papers which change our thinking, based as they are on meticulous observation, logical deduction and a willingness to go against the prevailing consensus when the evidence demands it. This is in stark contrast to the common creationist charge that scientists are forced by some sort of peer-pressure or conspiracy or condition of funding to conform to the prevailing dogmas and orthodox doctrines of the scientific world. In fact, the greatest respect is reserved for scientists like Alison Jolly who not only have the courage, honesty and integrity to change their minds, but give us the reasons to change ours too.

As one might expect, the charge creationists level at science is especially applicable to them, which is why they probably try to smear science with their own failings. Creation pseudo-scientists, for example, have to take an oath that their findings will never contradict anything in the Bible story of Genesis, as a condition of receiving financial support from the Institute for Creation Research or publishing in their publications or websites. Their much-vaunted process of 'peer-review' is simply a check to make sure they have kept their agreement. No self-respecting real scientist would agree their conclusions or promise not to challenge established science in advance of their research as a condition of funding and/or publication. Any who did so, or who hawked themselves around to the highest bidder, would quickly lose all credibility in the scientific community.

This is why science is a very different thing today to that in 1814 and almost unrecognisable when compared to that in 1714, whilst theology is virtually indistinguishable from that of the 18th and 19th-centuries and creationism hasn't progressed in the last 4000 years.

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