This is the second part of my review of Steve Stewart-Williams’ book The Ape That Understood the Universe. The first part can be read here.

Chapter 4: Romance, Relationships and Reproduction

The fourth chapter continues the discussion on sex differences but more in the context of relationships. Relationships are important as they facilitate reproduction:

“humans are not machines designed to last forever; they’re machines designed to last long enough to reproduce.”

Attraction is obviously important if a relationship is to occur. The importance of symmetry in attractiveness is explained which I found very interesting. ‘Symmetrical’ individuals are not only healthier and more fertile but also tend to have more sexual partners. This is because symmetry is harder to create biologically than asymmetry and symmetry enhances beauty. Beauty here is described as ‘a certificate of good health’.

In terms of what men and women uniquely find attractive, it is noted that men typically desire women with an ‘hourglass’ body shape. This includes traits like a large bust, a thin waist and a low waist-to-hip ratio (WHR). Low WHR is an indicator of youthfulness and fertility. Older women have a high WHR and are obviously less fertile. ‘Facial femininity’ is also desired by men in women. This includes features such as large eyes, small nose, high cheek bones, full lips, etc. Again, these are all related to youthfulness.

What women desire in men appears to be more complicated. Some masculine traits such as having a deep voice or a beard may have evolved primarily to intimidate other men rather than attract women. Studies have apparently found that women prefer slightly feminine faces for long-term mating and more masculine features for flings. This might be linked to women’s ovulation cycle although this isn’t mentioned in the book. I’ve read elsewhere that women who are approaching ovulation can subconsciously dress in more revealing clothing and be more attracted to alpha, masculine men because of a higher sex drive which suggests a reproductive function. The desire women could have for more feminised faces in men may be more to do with decreased sex drive after ovulating.

Not to labour on this point too much, but again I noticed a slight favouritism shown towards women, or femininity at least, here. Steve Stewart-Williams argues that whilst femininity is always desired by men, masculinity may not always be desired by women:

“in the context of pair bonds and parenting, masculinity isn’t always a blessing.”

Why not? Is femininity always a blessing? It’s worth pointing out that men have traditionally been expected to protect their women and children from harm if necessary which is far more important in long-term relationships than flings. More masculine men would be better at doing this than less masculine men.

Similarly, is femininity always linked to long-term relationships? By this logic, same-sex female relationships should be the most stable and peaceful of all types of relationships yet not only are lesbian couples more likely to divorce, but violence is more prevalent in same-sex couples than heterosexual couples. I’ve read somewhere that lesbian couples are, on average, the most violent although I couldn’t find anything to confirm that. You could argue that lesbians may have more testosterone than most women but they still have less than most men.

At the end of this chapter it’s noted that men’s testosterone levels decline in pair-bonds and more so when they become fathers whilst bachelors apparently have more testosterone. This could be a built-in adaptation for pair-bonding as testosterone increases sex drive which, if committed men’s testosterone levels remained the same as when they were single, could make them more tempted to sleep with other women.

Even so, men who were husbands and fathers were traditionally expected to uphold masculine virtues that they could pass onto their sons or their families in general. Some online commentators have suggested that the problem with boys and young men today is not ‘toxic masculinity’ but a lack of masculinity from limited contact with fathers or male teachers. This shows that masculinity should be something that women desire in long-term relationships as well as flings.

I’ll shut up about this from now on.

Other interesting topics explored in this chapter include:

• A description of the ‘Westermarck effect’. Named after a Finnish sociologist, this is the phenomenon of ‘negative sexual imprinting’ – i.e. humans and animals who are raised together don’t find each other attractive. This is commonly seen in the revulsion people feel towards incest. To what extent animals follow this rule however has been debated. A old Chinese custom called ‘sim-pua’ whereby a boy and a girl in an arranged marriage were brought up together in the boy’s family led to marital difficulties like infidelities. Bizarrely, it is said that girls who reunited with their family found themselves attracted to their male relatives. Similarly, although siblings in the ruling families of Ancient Egypt married each other, this was mainly for political purposes. Cleopatra married two of her brothers but also had children with the famous Romans Julius Caesar and Mark Anthony. Tutankhamun was the product of incest but had stillborn children with his half-sister and died at a very young age.

• Romantic love or ‘passionate love’ leads to intense physical and psychological symptoms – obsession, high energy, mood swings, sexual desire, etc. but is also fleeting – ‘the sizzle often fizzles’. It is likely linked to reproduction as we often don’t know much about the person we may be ‘in love’ with at first so we project things onto them. Like sex, the intense feelings may disappear after we have interacted with the object of our affection! Ideally, romantic love should lead to ‘companionate love’ – there’s a nice quote from Captain Corelli’s Mandolin here – where sex isn’t the central component. Companionate love allows couples to stay together which is important for raising very dependent offspring which humans have.

• Men and women tend to be jealous about different things regarding their partners. For men, sexual jealously is common as they fear paternity fraud if their wives cheat on them. Women, on the other hand, are more likely to feel emotional jealousy as they fear abandonment. Both men and women can feel sexual and emotional jealousy though as these are often interlinked.

• The ‘Cinderella effect’ – children are more likely to be killed by a step-parent than a biological parent. Humans however commonly care for children who are not their own without harming them.

• Humans are likely ‘mildly polygynous’ as, unlike in species like birds, males are slightly larger than females which is, according to David Barash, “one of the hallmarks” for a polygynous species. In many civilisations some men have had multiple wives although pair-bonding has always been common as well.

• Animals that have promiscuous mating systems, such as chimps and bonobos, engage in ‘sperm competition’ as females can have many different males’ sperm in their reproductive tract. As a result,  males who produce the most sperm have a better chance of reproducing so these species have very large testicles relative to the size of their bodies. Males in monogamous/polygynous species like humans and gorillas have much smaller testicles.

Chapter 5: All About Altruism

In the penultimate chapter, the focus shifts from human relationships to the altruistic tendencies of humans and animals. Many organisms will risk and sacrifice their lives to save others – whether it’s a soldier diving on a live grenade to protect his fellow troops, a bird pretending to be injured to distract a predator away from its eggs or a bee using its stinger to protect its hive. How could such behaviours evolve if evolution is a brutal struggle for survival? Like in the other chapters, both biology and culture are considered.

It is pointed out that both humans and animals favour kin over non-kin, a key component of William D. Hamilton’s ‘kin selection theory’. People’s greater willingness to help their relatives over non-relatives is one evidence of this, particularly for a ‘high-cost’ altruistic act like donating an organ. Further evidence of this tendency can be seen in the fact that people leave most of their inheritance to their relatives and are also more likely to kill a non-relative than a relative – a call-back to the ‘Cinderella effect’ in Chapter 4. Kin altruism has even been observed in plants and bacteria. All this makes perfect sense from an evolutionary standpoint as kin share genes with each other so it is mutually beneficial for them to help each other.

One way in which humans differ from other organisms is our intense ‘groupishness’. For the most part, we have been able to live in large populations without killing each other and cooperated in building large, complex civilisations. We can be very generous to complete strangers and dislike those we feel are taking advantage of another person, even if we don’t know them. Humans have also fought and died for a particular group, such as a religion, an ideology or their own country. The downside of this group solidarity of course is there is often antagonism towards other groups, reflecting Jonathan Haidt’s point that groups make us team players but not saints.

It has been speculated by some that ‘group selection’ has overridden individual selection as ‘extreme altruism’ – acting for the good of the group, benefitted the group as a whole. Stewart-Williams, however, disagrees with ‘group selectionists’ and instead argues that humans are more individualistically minded. People generally have to be given incentives in order to cooperate and punishments to discourage destructive behaviour. He also points out that, whilst examples of ‘extreme altruism’ such as the aforementioned soldier sacrificing himself are admirable, they’re also rare. Our altruism towards others beyond our kin likely evolved from living among smaller groups where we would encounter the same people on multiple occasions and so would have to regularly cooperate with them. Large scale cooperation, then, may be an example of evolutionary mismatch.

The fact that altruism is motivated in part by self-interest has led to some people being upset by its implications. George R. Price, a colleague of Hamilton, was said to have been so depressed by the idea that altruism is primarily self-interest that he started performing random acts of kindness towards strangers. This depression may have contributed to his eventual suicide although that could have been chiefly motivated by his suffering from thyroid cancer. Steve Stewart-Williams notes the irony of humans being upset over our self-interested tendencies as this suggest humans aren’t so selfish after all. He argues that humans are likely a ‘grey area’ – somewhere between being selfish monsters and selfless angels which is my general feeling as well.

Whilst reading this chapter, I couldn’t help feeling it could have been a little shorter as a lot of this seems obvious and is briefly covered elsewhere in the book. Steve Stewart-Williams argues though that the most obvious tendencies need the most explaining.

There is still a lot of interesting information presented here. To summarise:

• Hamilton’s rule: called the ‘E = mc² of evolutionary psychology’ by Oliver Curry, this equation (br > c) states that the benefits of an altruistic act can be large enough to compensate any cost to the altruist, with ‘b’ being the benefit, ‘r’ the ‘degree of relatedness’ between an altruist and recipient and ‘c’ obviously being the cost of the act. The ‘degree of relatedness’ is the probability of 2 organisms sharing the same genes due to shared ancestry. Because offspring share 50% of their genes with each parent and each sibling, the degree of relatedness, r, would equal .5 between them. For grandparents and grandchildren, this would be .25, for cousins, .125 and so on. Essentially, the higher the value of ‘r’, the more the benefit of an altruistic act will outweigh any cost the act may cause. This explains partly why we’re more likely to help relatives, particularly close relatives, over non-relatives.

• Humans and animals don’t necessarily favour kin naturally, but instead favour ‘kinship cues’ such as early life cohabitation or phenotypic similarity. Scientists who swapped around litters of squirrel pups found that the pups were still close to those they were nursed with even if they weren’t related.

• Altruistic acts can be forms of delayed co-operation: a favour from one person to another can be returned in the future – Robert Trivers’ reciprocal altruism theory. Trivers argued that humans have emotional preferences that lead to us desiring reciprocal relationships. We get angry if we’ve been cheated and feel gratitude if we have received help. We’re also more concerned that non-relatives return favours more so than relatives as the costs will often be greater in these circumstances.

• Reciprocal altruism has been tested using computer simulations. In one simulation, different computer programs interacted with each other and were programmed with unique strategies when they encountered another computer program – e.g. ‘Always co-operate’, ‘Always defect’. Points were awarded depending on how the programs responded in their encounters. For example, ‘free-riding’, whereby one program defected and the other co-operated, would give the defector 5 points and the co-operator 0. Mutual co-operation would give each 3 points and mutual defection would give each only 1 point. The program with the strategy ‘Tit-for-tat’ usually earned the most points as it co-operated in its first interaction and then copied the response it received from a program on a second encounter – i.e. if it got a defection from a particular program it would defect it next time, etc. More sophisticated strategies have been designed which have been more successful but ‘tit-for-tat’ is still reflective of how organisms tend to interact amongst themselves.

• Vampire bats have been observed operating a ‘tit-for-tat’ strategy as they sometimes regurgitate blood taken from their prey for other bats who haven’t fed, especially if the recipient bats have shared blood with the altruistic bats previously. This is an interesting (albeit disgusting) example considering that we tend to think of vampires in general as predatory and exploitative.

• Altruism may be ‘a peacock’s tail’ – a form of sexual selection. The evolutionary psychologist David Buss has found that, cross-culturally, both men and women desire kindness in a long-term mate. ‘Big game hunting’ in hunter-gatherer societies may also function more as a form of sexual selection rather than simply to obtain food as it would be easier and less dangerous for hunters to catch smaller prey. Hunters are also expected to share their spoils with the rest of the tribe rather than keep it for themselves. Culturally, it is a test of strength, skill and bravery and the best hunters tend to have more sexual partners.

Chapter 6: Memes on the Mind

The final chapter in the book focuses on culture and how cultural evolution affects human beings. Before I read the book, I skimmed through the chapters and wasn’t that interested in this one as much as the others. When I read through it properly, though, this chapter turned out to be one of my favourites.

The theory of ‘memetics’ is presented by the author as how the evolution of culture operates. Stewart-Williams believes this theory can act as a unifying framework even if it is not the one true answer to the question of how culture develops over time.

‘Memes’, which were mentioned in Chapter 2, are ‘units of culture’ that spread like genes and are subject to the same pressures such as nature selection. Memes can be trivial or of great importance. Intriguingly, ‘memes’ are themselves a meme as the word has passed into common usage and outcompeted similar terms like ‘cultural variant’ and ‘culturgen’.

Like the ‘gene’s eye view’, Steve Stewart-Williams believes that memes act ‘selfishly’ in order to spread and be passed on. In this way, memes don’t have to be good for people in order to thrive in culture but generally are as this works to their advantage. In short, memes are successful if they are good for themselves rather than good for people. Examples of memes that are disadvantageous to us are chain letters, hoax emails and cultural practices like smoking.

Memes can be established whether or not humans have deliberately created them. I really liked the section on ‘blind selection’ which explains how certain things can appear to be ‘intelligently designed’ but are in fact shaped by trial and error and experience. One example of this is Breton fishing boats. Boats that could withstand the unpredictable ebbs and flows of the sea were copied and those that failed and sunk were discarded. Effectively, a rule of ‘whatever works’ operated in ‘selecting’ what types of boats were produced. The French philosopher Alain noted that “the sea herself…fashioned the boats”.

Another example is the development of teddy bears. Over time, the toy bears gradually became cuter and more baby-like in response to market forces after initially being uglier and thinner. In both cases, nobody sat down and designed these successful products from scratch – they had to be developed over time by observation.

This reflects how we came to understand and influence human behaviour. Thinkers from Jordan Peterson to Nassim Nicholas Taleb have pointed out that first humans have to act and then observe themselves acting in order to figure out how we function in the world. Our understanding of ourselves is often ‘after the fact’. This is also evident in institutions that have been shaped by human nature such as the law: the American Supreme Court Justice Oliver Wendell Holmes observed that “the life of the law has not been logic but experience.”

Stewart-Williams summarises this phenomenon when he says:

“we’re swept along by currents we barely understand and over which we have little control.”

Religion, like the law, in another institution that deals with human nature but how much religion is a product of blind selection itself is one of intense debate. It is presented here as a collection of memes or a ‘memeplex’ but more on that later.

Language is a common example in this chapter of how a cultural product operates like an evolving gene or organism. Languages aren’t designed but develop across time and can go extinct if they are no longer used. Words are created and discarded and languages can be subdivided into dialects or eventually brand new languages. Like a family tree, languages can have a common ancestor – e.g. French and Spanish share a common ancestor in Latin. Language however is also a product of biological evolution as young children have evolved to pick up language very quickly.

Science is another example of a human invention that works like evolution. The science philosopher Karl Popper described scientific knowledge as being an evolutionary process as it involves variation and selection of theories. Tested theories that prove to be correct are ‘selected’ whereas theories that are unproven or disproven are discarded. A scientific theory can also ‘evolve’ to become more accurate.

Where memes and culture differ from genes and biology is how they are spread and passed down across generations as we are culturally influenced by many things whereas we are only genetically influenced by our families. We have been able to advance our technology and knowledge of the world by building on the work of those that lived before us – ‘cumulative culture’. Stewart-Williams points out that it would take one human millions of years to acquire all of the understanding of the world that many generations of humans have gathered and passed on to others. Whether we are great thinkers and innovators or just ordinary people, we are reliant on the knowledge of others to be able to function in society. This is increasingly the case as we become ever more technologically advanced.

“we’re surrounded by machines and technology whose inner workings we don’t understand and could never hope to understand. Humans are chimpanzees reciting Shakespeare – dunces with the technology of geniuses.”

This ability to build on existing knowledge is in large part due to our ability to imitate and copy others – ‘adaptive culture’. But which memes do humans copy and pass on? Like in Chapter 2, which deals with evolution from a biological perspective, here several hypotheses of cultural evolution are explored to explain its function, such as the idea that its primary purpose is to enhance inclusive fitness – boost survival and reproduction. Evolutionary theorists like E. O. Wilson state that people have evolved to latch onto ‘fitness-enhancing memes’ and ignore fitness-diminishing ones.

Culture nevertheless evolves independent of considerations of an organism’s ‘fitness’ as often what is good for the group takes precedence over what is good for the individual in many cultures. Individuals may suffer or benefit from memes designed to benefit the group. As has already been pointed out, some memes can also be circulated even though they have no apparent benefit to the group or individual – annoying scam emails, ‘earworms’, bad habits, etc.

This leads to the final hypothesis of what cultural evolution is about: the survival of the fittest memes. But what determines which memes are the ‘fittest?’

Come back soon for the third and final part of this review!