The Mating Mind by Geoffrey Miller
Chapter 6: Courtship in the Pleistocene
The evolution that shaped human nature all took place in the Pleistocene, and Miller uses this chapter to explain sexual selection in our ancestors and how that now pertains to our own generation of individuals. The Pleistocene era was used because when it began, “our ancestors were relatively small-brained apes who walked upright and made just a few crude stone tools… [and] at the end of the Pleistocene…our ancestors were already modern humans, identical to us in bodily appearance, brain structure, and psychology. The evolution that shaped human nature all took place in the Pleistocene” (180).
Our ancestors were very communal and lived together in small groups that would move often. Females would group with other females and their children based on food resources and protection, while the males would be drawn to wherever there were females (181). Although they gathered and hunted for their own food for survival, they most likely had much more leisure time compared to ourselves. The threat of danger and death was probably minor and they, “like most great apes, probably spent their time worrying about social and sexual problems,” as opposed to concerning themselves with survival problems. (182).
Sexual Selection in Primates
Miller argues that monogamy in the Pleistocene arose through food distribution. When there is more of a benefit for females to find food alone due to food being greatly dispersed, the males as well would then separate and start forming pairs with the singled females. This pattern can be seen in gibbons, some lemurs, and some African and South American monkeys.
In instances where food is in “patches large enough for several females to share, they tend to band together…[and] as long as the female band is not too large, a single male can exclude other males from sexual access” (183). The “harem-system” described here is found in hamadryas baboons, colobus monkeys, some langurs, and gorillas (183). “The competition between males to guard the female groups creates very strong sexual selection pressures for male size, strength, aggressiveness, and large canine teeth.
If food is spread out so much, and female groups are too large for one male to protect, then the males “form coalitions, resulting in a complex muti-male, muti-female group, as in some baboons, macaques, ring-tailed lemurs, howler monkeys, and chimpanzees. With many males and many females, the females tend to mate with all the males, and vice versa, so the sperm end up competing with other sperm inside of the females. Due to this “sexual selections for good sperm, male chimpanzees have evolved large testicles, copious ejaculates, and high sperm counts” (183). These “multi-male groups allow greater scope for females to choose between males” (184).
Although we are not entirely certain about female primate preference, there are three kinds of female preference that have been studied: one is a preference “for high ranking males capable of protecting females and offspring from other males; [second is a] preference for male “friends” that have groomed the female a lot and have been kind to her offspring; [and third] is a preference for new males from outside the group, perhaps to avoid genetic inbreeding” (184). Each of these is easily explained by “female choice for good genes or female choice for material and social benefits” (184).
“Most primates follow the general animal pattern of male sexual competition and female choosiness. But when the costs of sexual competition and courtship are high, males also have incentives to be choosy” (185). They become “choosy about how they spread their sexual effort among the available females” (185). Chimpanzees and Bonobos (who are our closest ape relatives) “live in multi-male, multi-female groups in which sexual choice is…complicated…. Both sexes compete; both sexes have dominance hierarchies, and both sexes form alliances. Sexual relationships develop over weeks and years rather than minutes,” (185) and many researchers predict that “our earliest hominid ancestors probably lived under similar social and sexual conditions” (186).
“Exclusive lifelong monogamy was practically unknown” (186). Serial monogamy was more common, in which there was a “sequence of nearly exclusive sexual partnerships that were socially recognized and jealously defended” (187).
Females had “incentives to mate with males of higher fitness than their current partner,” and males had “incentives to mate with as many females as possible;” and the “higher incentives for males to attract large numbers of sexual partners through public displays of physical and mental fitness explain why males are so much more motivated to produce such displays” (187).
Concealed ovulation in females reduced the male incentives for rape, and thus, it “guarded [female’s] power of sexual choice” (187). However, miller states that the “prevalence of rape in human prehistory is still subject to intense debate…and the higher the actual prevalence was, the less important female mate choice would have been, and the weaker [his] sexual choice theory would become” (188).
Pleistocene Flirting Versus Modern Dating
Modern courtship compared to prehistoric courtship is incredibly different. In modern society, we pay people to entertain and impress our dates for us. We use consumerism to make “courtship a commodity that can be bought and sold” (188). Back in prehistoric times, people didn’t have the gadgets we have now to keep our partner interested once the romance period passed, and so, as Miller says, “if they were bored in the relationship…they either had to put up with your boring old self, or find a new lover” (189). He explains that “during prehistory, there were fewer economic incentives to stay together, fewer distracting entertainments to replace lost romance, and fewer ways to insulate oneself from new opportunities,” so there was no need for the lifelong commitments (189).
Were Fathers Important?
“Human females have inherited a rich set of mental and physical adaptations fully sufficient to nurture their offspring with minimal assistance from males” (190). It is because of this that, while mothers may have had boyfriends around, they may have not been the father of all or any of her offspring. And because males were unsure of their paternity, they would “invest much more in pursuing new sexual opportunities” than they would invest in offspring that may not be their own (190). Another argument against the importance of fathers was the misconception that males were needed to protect the females and the young. But actually, the females, being only 10% shorter than the males, were not disenfranchised physically. In addition to this, the groups formed by the females sufficed as a protection system as perhaps even better than the protection they would receive from an aggressive male. Males are even seen as a burden at times due to several factors: they may “eat more than they provide, and [may] demand more care than they give one’s child” (191). Aside from this though, there is still discussion about father importance in human evolution, and there may be a correlation between courtship and parenting (192).
Combining Courtship and Parenting
Surprisingly, “most courtship during most of human evolution occurred between adults who already had children by previous relationships.” Miller states that they must have “juggled their courtship efforts with their mothering” and this meant hat they may have turned “normal motherly duties into better fitness indicators” (193). Therefore it is not very shocking that “sexual competition between females was mostly sexual competition between mothers” (193). So as a result of this, “male hominids had to appeal not only to mothers but to their children,” and because of this, the argument follows that since the “children’s judgments influenced mate choice, then they influenced sexual selection, and children’s preferences indirectly shaped the evolution of adult male humans” (193). Through this argument, the belief has been adopted that “paternal effort may actually have evolved through sexual choice as courtship effort. Men attracted women by pleasing their kids” (194). However, “men in every culture are about a hundred times more likely to beat and kill their step-children than their genetic children” (194).
Where Sexual Choice Did Its Work
In order for any evolutionary effect to be found from sexual choice, “different individuals must produce different numbers of surviving offspring by virtue of their sexual attractiveness” (195). Also, while “polygyny helps to explain sex differences” due to the “sexual selection pressures for males to display more intensely than females…, we should not assume that sexual selection requires polygyny” (195). Miller begins to explain one possibility of sexual choice:
Male and female hominids both tried to attract the best sexual partner they could. If they liked that partner’s company, they hung out a lot together, had a lot of sex, and produced a child. If they still liked each other after the baby arrived, they stayed together and produced another one. If they did not, they separated and looked for the best new partner they cold find. Most hominids spent most of their lives in some kind of sexual relationship with somebody. Most sexual relationships longer than a few months produced at least one child (196).
Sexual Selection When Everyone Finds a Partner
Miller explains that in a tribe with a strict monogamous tradition, every person will want to attract the “highest-fitness mate they can, because they want the best genes for their offspring” (196). Therefore the process will look very balanced; technically speaking, the highest ranking male will get the highest ranking female, and the second highest ranking pair will settle for each other since they lost their chance with the highest ranks, and it will follow like so.
Fitness matching is used to create “the widest possible fitness differences between babies” and it increases fitness in variance in future generations (198). Miller argues that the “fitness spreading effect is important because it creates a very tight link between sexual selection and natural selection” (198). The greatest effect of the fitness spread is that when the “low-fitness” babies die off over evolutionary time, the low-fitness mutations die with them; and vice versa, the helpful mutations in high-fitness babies survive and their genes thrive (199).
From Fitness Matching to Fitness Indicators
How does fitness matching affect the fitness indicators? The fitness indicators would be the sexual ornamentations and courtship displays. Although the highest-fitness individual would usually attract the highest-fitness mate, there was no way for our ancestors to be able to “see” fitness ability, so therefore, an individual with a less high-fitness quality would try to attract the highest-fitness mate through sneaky tactics. One way he/she would do this is by producing “an appearance of higher fitness by allocating more energy to her fitness indicators” (200). Her offspring will then not only carry high-fitness genes, but also the inherent ability to “allocate more energy to their sexual ornaments and courtship displays” (200). This example displays how sexual choice can drive sexual selection. Fitness matching can explain ornamentation in monogamous birds, and therefore may be able to explain courtship abilities in our own species (201).
Sexual Selection Without Sex Differences
However, in response to the previous argument on fitness spreading, Miller adds that “fitness matching tends to promote sexual equality in the indicators it favors” and in doing so, does not reveal a sex difference (202). To explain these sexual ornamentations that appear in both sexes, early biologists have said that those traits are simply “species recognition markers”—ways to distinguish species from each other, and “if the marker was displayed vigorously by both sexes during mutual courtship, biologists would say that the animals are performing a “pair-bonding ritual” (202). However, Miller says that this “terminology obscured the fact that one individual would often walk away from the ritual, unimpressed by his or her would-be partner. Miller somewhat facetiously says that this “viewpoint implies that the hours of mutual conversation during human courtship are likewise nothing more than a way for us to tell that the other individual is a human rather than a chimpanzee” (202). Therefore, he concludes, “fitness matching, a form of mutual mate choice based on fitness indicators, may be a more sensible explanation for most sexual ornaments that show very small sex differences” (203).
In Search of a Few Good Hominids
To make their sexual choices, our ancestors relied on traveling in and between “bands,” which is “the small group of individuals with whom a hominid would forage and spend most nights” (203). Because interactions between bands were very short, quick judgments had to be made in order to decide if it was a band that may spark some sexual interest or opportunity. These judgments were probably based on “physical appearance, bodily ornamentation, apparent social status, and public display behavior” (203). Basically, Miller simply states that there would be a basic pattern of processes that the males and females would engage in once finding mutual attraction. “Males would scan for physically attractive females and pursue them….Once a male tried to approach a female to form a consortship, the first stage of female mate choice would be triggered. On the basis of his appearance and behavior, she would reject him or provisionally agree to continue interacting. This would impose sexual selection on males to create a positive impression during the first few minutes of interaction. After several hours or days of consorting, the female would decide whether to have sex. If she agreed, they would probably copulate frequently for several days or weeks. At that stage, male mate choice would once again reassert itself: will he stay with this female, or grow bored and abandon her in search of someone who would make a more interesting long-term partner? The female would be deciding the same thing: does he offer anything beyond a few good orgasms and some good times?” (204). This is how the process of mate selection took place most likely, and it can also be examined in our own generation similarly.
Very Simple Rules Can Lead to Very Good Sexual Choices
Miller says that “very simple rules of thumb can result in sexual choices that are almost as good as the best strategies developed through mathematical analysis” (207). “Each trait that we consider sexually attractive already summarizes a huge amount of information about an individual’s genes, body, and mind” (205). There are three simple rules that Miller describes in this section: “Take the Best,” “37% rule,” and the “Try a Dozen” rule. The “Take the Best” rule says that you decide which qualities are most important to you, say beauty and intelligence, and then go down the list of potential mates and if one is more intelligent than the other, pick that one, or if not, if one is more attractive than the other, pick the more beautiful one. The only problem with this rule would be that it may not require fast decision making, since “conversations during courtship are how we learn the most about potential mates, and these conversations take time” (206). And even though it seems as though men can quickly make their decisions based on physical attractiveness alone, “when it comes to making long-term sexual commitments based on traits that are more than skin deep, men may take even longer than women” (206). The second rule, the 37 percent rule, comes into play when searching through a number of prospects and deciding on a serious relationship. This rule suggests that you “interview” the first 37% of all your potential mates, and keep in mind the best one. Then, as soon as you find one candidate that is better than that best one, keep that one. The final idea is called the “Try a Dozen” rule, and it works better than the 37% rule because “interviewing” that many people is very time consuming. All you do is “interview a dozen possible mates, remember the best of them, and then pick the very next prospect who is even more attractive” (207). This is the process by which humans seem to follow, and these rules “impose sexual selection that is almost as strong as the most complicated, perfectionist decision strategy” (207).
Indicators for Qualities Other than Fitness
Fitness is not the only factor involved when attracting a sexual partner, but rather they should be interested in “mates in good health because they are more likely to survive as partners and parents,… [and] mates capable of efficient cooperation and coordination, so they make an effective team”; these can be assessed through energy level kindness indicators (208). Direct and indirect benefits of mate choice are examined, where “food gifts, nests, territories, and fertility” are classified as “direct” benefits, and good genes are “indirect” benefits. While getting good genes are great, wouldn’t you rather receive something tangible, as in a direct benefit? This is what Miller suggests is our way of using direct benefits to actually obtain our indirect benefits. If a male is protecting a food territory for females, he must be the strongest. The woman will copulate with that male not because he has supplied her with food, but for his inherited genes to protect his owned territory. “The females may be using the cue of resource-defense ability mainly to get good genes, not to get food” (210). The same goes for humans as well: “Ancestral women may have preferred intelligent, energetic men for their ability to hunt more effectively and provide their children with more meat. But I would suggest it was much more important that intelligent men tended to produce intelligent, energetic children more likely to survive and reproduce, whether or not their father stayed around. In other words,…evolutionary psychology has put too much emphasis on male resources instead of male fitness in explaining women’s sexual preferences” (211).
Age and Fertility
Age and fertility go hand in hand in our history and there is no denying it. “Individuals before puberty are infertile. Female adolescents are significantly less fertile than 20-year-olds. Female fertility declines gradually during the thirties, and declines steeply after age 40. Women after menopause are infertile” (212). It is possible that there may have been males attracted to infertile females, however, they would have produced no offspring, and therefore have all died out since. Not surprisingly, in the Pleistocene age, the more attractive females would have been those who were older and had children already simply because it showed they had high fitness ability to survive and raise offspring. Just like fitness indicators, where one could deceive their partner into believing they are higher fitness than actuality, age indicators are similar. The term “neoteny” is used in this section which is the idea that we have maintained the face of a baby chimp, to retain youthfulness, however, this argument does not hold substance, and the “deceptive youthfulness indicators must have evolved through some form of sexual or social selection” (214). What Miller suggests instead is that youth indicators may be a form of fitness indicators. So, “any mate choice mechanism that evolved to favor a condition dependent indicator will tend to favor youth over age simply because youths will display the indicator in a healthier condition” (215).
Fitness Indicators for People Other than Mates
Fitness indicators were not only used for sexual selection, says Miller, but also used in forming friendships and other similar relationships, such as parent-child. It is argues in this section that we look for similar traits in our friends as we do in our mates, and as is quotes, “the overlapping use of fitness indicators in sexual and non sexual relationships is why making friends so often feels like a variant of sexual courtship” (216). Besides friendships, the relationship between parents and their children is a very important one. When children crave their parent’s attention such as in the comment, “’Hey dad, look at this,’” the child is trying to prove something to the parent. Miller says this may have evolved because parents may at one time have had to “choose how much support to invest in a particular child” (216). And contrastingly to Freud’s belief that children would display their fitness indicators to their parents because of a hidden desire to want incest, it instead may simply mean “that they want parental support” (217).
Although Miller makes sure to state that there is definitely nothing “unnatural” about homosexuality, he makes it clear that homosexual behavior is not very important to evolution simply for the reason that it doesn’t lead to offspring, and therefore none of our ancestors could ever have been descendents of “exclusively homosexual hominids” (217).
Mate Choice and Courtship as Social Events
Because we share similar genes with our relatives, it is beneficial for us to meet and interact with the relatives of our mate in order to assess their “fitness.” This was easily done by our ancestors since social life for them highly involved family relations. Miller sates that “if sexual choice paid attention to the fitness of a potential mate’s relatives, then those relatives would have been under sexual selection to display high fitness….Any courtship effort that helps your relatives to find good mates helps your own genes to spread” (219-220). It is our “collective courtship by relatives [that] might explain why humans are so good at producing certain kinds of cooperative display” (220). Instances when we see this in our own culture is the ability for parents to show off their resources and “familial fitness” when children hit puberty, such as having bar mitzvahs, quinceneras, and sweet sixteen parties. Therefore, “cooperative group activities may have evolved as collective courtship displays through sexual selection. However, Miller refutes this by explaining that our use of collective fitness displays may be used for “intimidating rival groups competing for the same territories and resources” (221). Although collective courtship didn’t hold up, collective sexual choice may. The family’s views of the potential mate surely had an influence on the individual’s decision. If a parent was not pleased with a child’s mate, they would vocalize their opinions “because the sexual choices of their children were so important to the number and quality of grandchildren who would carry their genes” (222).
The evolution that shaped human nature all took place in the Pleistocene, and Miller uses Chapter 6 to explain sexual selection in our ancestors and how that now pertains to our own generation of individuals.
I. Pleistocene Life
A. Our ancestors lived a very communal lifestyle in small groups that moved often.
1. Females grouped with other females and their children
2. Males moved to wherever the females where
3. Hunting and gathering was their livelihood
4. Enjoyed much more leisure time than we do
II. Sexual Selection in Primates
A. Pleistocenes practiced monogamy or harem-style living for purposes of food distribution
1. Monogamy: when food is scarce, it is more beneficial for females to find food alone, therefore males will begin to separate and pair off with single females.
a. This pattern is seen in gibbons, lemurs, and some African and South African monkeys
2. Harem-style: When there is an abundance of food, females tend to band together, and a single male can exclude other males from sexual access.
a. This pattern is seen in hamadryas baboons, colobus monkeys, langurs, and gorillas.
3. Complex multi-male/multi-female: if female groups are too large for one male to protect, males will band together to form “coalitions”
a. Sperm compete with other sperm already inside the females
b. This results in sexual selection for good sperm
B. Female primate preferences might follow three types of preferences
1. Preference for high ranking males capable of protecting females and offspring from other males
2. Preference for male friends that have groomed the female a lot and have been kind to her offspring
3. Preference for new males from outside the groups
a. This may help avoid genetic inbreeding
C. Males show choosiness or preference when the costs of sexual competition and courtship are high.
III. Pleistocene Mating
A. The most common practice of mating seemed to be serial monogamy
1. Females had incentive to mate with males of higher fitness than their current partner
2. Males had incentive to mate with as many females as possible.
a. Concealed ovulation reduced male incentive for rape and guarded female power of sexual choice
IV. Pleistocene Flirting Versus Modern Dating
A. Instead of being able to entertain themselves with the modern conveniences that we have such as movies, dinner dates, etc. our ancestors either put up with boredom or moved on to find a new partner.
1. This made lifelong commitment unnecessary
a. Fewer economic incentives to stay together
b. Fewer distracting entertainments to replace lost romance
c. Fewer ways to insulate oneself from new opportunities
V. Were Fathers Important?
A. Human females have inherited many adaptations fully sufficient to care for their offspring with little help from males.
1. Males were unsure of their paternity
2. Females may have had their boyfriends, but they may not have been the father of their offspring
3. It is a myth that males were needed to protect the females and young
a. Females were only 10% shorter than males and were not physically disenfranchised.
b. Female groups served as strong protection groups
c. Males seemed to be burdensome at times –more to feed, etc.
VI. Sexual Selection When Everyone Finds a Partner
A. According to Miller, in a tribe with strict monogamous tradition, every person will want to attract the highest-fitness mate that they can.
1. The highest ranking male with get the highest ranking female
2. The second highest ranking pair will settle for an other and so on
B. Inevitably, due to fitness spreading those with the high-fitness genes with survive and thrive.
VII. Effects Of Our Ancestors Traveling In Bands
A. Brief interaction between bands, or groups
B. Quick judgment needed to sexually assess others
VIII. Three Rules for Sexual Selection
1. “Take the best” rule
a. Use preferential qualities to choose mate
i. For example, one would list the potential mates and use intelligence as the deciding factor. The smartest potential mate would be chosen
2. “37 Percent” rule
a. “Interview” the first 37% of the potential mates, keeping in mind the best one, and pick the next best potential mate
3. “Try a dozen” rule
a. “Interview” the first twelve potential mates, keeping in mind the best one, and pick the next best potential mate. This is quicker than the 37% rule as the interviewing is not as time consuming
IX. Indicators of Non Fitness Qualities
1. Good health
2. Efficient cooperation and coordination
X. Age and Fertility
1. Age and fertility go hand in hand
a. Before puberty females are infertile
b. Females in their 20s are very fertile
c. Fertility declines in 30s
d. After menopause, women are infertile
2. Youth is preferred as it shows more fitness/health indicators
XI. Fitness Indicators for People Other than Mates
1. We look for similar traits in our friends as we do in our mates
2. Children crave parent’s attention
3. They try to prove things to their parents (indicators)
XII. Gay Hominids?
1. Homosexuality is not unnatural
2. Since homosexuality does not lead to offspring, no ancestors could have been descendents of “exclusively homosexual hominids”
XIII. MATE CHOICE AS A SOCIAL EVENT
1. Since we share similar genes with our relatives, we should take interest in the fitness of our mate’s relatives
2. If parents are not pleased with their child’s mate choice, they will tell them because they want their grandchildren to have the best possible genes
n Interesting that fitness-indicators play such an important role in mate selection. Contrary to belief, Miller argues that females select mates based on direct benefits to assess the indirect benefit: having good genes.
n Also contrary to modern thought was that males were not needed for protection, and in fact were even bothersome to be around. This, however, makes one wonder how the females would have enough food without the male since she is taking care of her child and unable to search for food. I suppose the group would support each other’s needs then and everyone helps everyone acquire food.
n I may disagree with Miller’s idea that females didn’t care about the male’s resources themselves but only cared that her offspring would inherit the genes of protection. It seems that if females didn’t get the resources, than she and her baby wouldn’t even survive to reproductive age.
n I also found it interesting how “sneaky” our species are: trying to hide our real age to look fertile, and trying to increase our fitness-indicators by putting all of our effort into making ourselves look like the highest-fitness mate, even when we are not.
n Criticism with the chapter was that it was very choppy. The sub sections did not flow. And he never made a clear argument. He would discuss an argument, and then refute it. It was hard to see his own point of view.