The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature (55 page)

inferences about personality from social behavior, so what they see in mate choice is pretty much all they get. Language lets us learn about potential mates much more efficiently and interactively than any other species can.

Are these life stories reliable as indicators of anything? Who has not been tempted, when sitting next to a stranger on an airplane, to make up an utterly fictional account of oneself, inventing a new name, origin, and occupation? But, as every undercover police officer knows, false autobiography is vulnerable to logical inconsistency, to claims being proven wrong, to insufficient background knowledge, and to accidental revelation of true identity by one's actual acquaintances. The life stories that we reveal over days and weeks of courtship are kept reasonably reliable by logical, empirical, and social pressures.

Of course, we present our lives in the best possible light. We mention our successes rather than our failures, impressive relatives more than wastrels, dramatic trips more than solitary depressions, and palatable beliefs more than secret bigotries. Our life stories present us as the heroes of the grand adventures that are our lives, rather than the Rosencrantz or Guildenstern to someone else's Hamlet. Nevertheless, because most people distort their life stories to more or less the same degree, they remain a valid basis for mate choice. Initially at least, our life stories will be compared not to the truth, but to the equally distorted life stories of our sexual competitors. You might effuse about your package holidays to Bermuda, while your rival reminisces about his or her space shuttle flights as mission commander. Even if you both hide your tendency to periods of indigence and self-doubt, a potential mate can still judge that flying a billion-dollar spaceship at 17,000 miles per hour is a better fitness indicator than a weekend of immoderate drinking at Club Med.

Our ancestors could not brag of orbiting the Earth, but neither can most of us. Our lives are generally safe and sedentary compared to theirs, so our life stories are probably less dramatic, and less informative about our ability to handle challenges and emergencies. By the time they reached sexual maturity, our

ancestors would have had plenty of close encounters with dangerous wild animals, some experience of physical violence, a great many travel stories concerning diverse places, and encounters with potentially hostile members of other tribes. By middle age, they would have seen death and injury, lost many relatives, and experienced sickness and starvation. Surviving males would have killed very dangerous animals, and perhaps killed another human. Surviving females would have suffered miscarriages, difficult births, the death of infants, sexual harassment, stalking by unwanted men, and perhaps rape. Our ancestors had plenty of life to fill their stories.

When life stories became important in verbal courtship, our ancestors began to judge one another's past experiences, not just their present appearance. Language made each individual's entire history a part of their "extended phenotype" in courtship. Like our body ornaments, our pasts became part of our sexual displays. We dragged them around after us, into every new relationship. As a result, sexual selection could favor any mental trait that tended to produce an attractive past. It sounds like a time-travel paradox, but it is not. It just means that sexual selection could have favored genes for a good autobiographical memory, a tendency to have risky adventures, or a credibly restrained sex life without too many infidelities. The handicap principle suggests that sexual selection could even have favored a masochistic taste for memorable discomfort, since the ability to survive hardship reveals fitness. Even in the carnage of mechanized warfare or the intellectual bloodbath of an academic job interview, one can always think, "This will make a hell of a story someday." Through memory and language, we can transform a pure fitness cost in the past (such as a physical wound or a social rejection) into a reliable fitness indicator in the present (a story about our ability to heal without disability, or to overcome depression).

Introspective, Articulate Ape Seeks Same

of our mental processes. Before language evolved, there may have been little reason for animals to introspect about their thoughts and feelings. If introspection does not lead to adaptive behavior, it cannot be favored by evolution. However, once verbal courtship became important, sexual selection pressures could have increased the incentives for being able to consciously experience more of the thoughts and feelings that guide our behavior, and being able to report those experiences verbally.

Lovers sometimes say, "Words cannot express what I feel about you," but this attention-getting device usually precedes hours of impassioned chatter or lovemaking. Articulate people can articulate anything that they consciously experience. Insofar as sexual choice favored verbal self-disclosure, it may have favored an expansion of conscious experience itself. The result is the effortless, fluid way we can translate from perceived objects through consciously attended qualities into spoken observations. We can walk with a lover through Kew Gardens, notice a rose, describe its distinctive color and fragrance, and perhaps even whisper a relevant quote from Shakespeare's sonnet fifteen, observing

Where wasteful Time debateth with Decay, To change your day of youth to sullied night; And all in war with Time for love of you, As he takes from you, I engraft you new.

This high-bandwidth channel, from perception through consciousness and memory to articulate communication, seems unique to humans. Only when sexual choice favored the report-ability of our subjective experiences—with the emergence of the mental clearing-house we call consciousness—did our strangely promiscuous introspection abilities emerge, such that we seem to have instant conscious access to such a range of impressions, ideas, and feelings. This may explain why philosophical writing about consciousness so often sounds like love poetry— philosophers of mind, like lovesick teenagers, dwell upon the

redness of the rose, the emotional urgency of music, the soft warmth of skin, and the existential loneliness of the self. The philosophers wonder why such subjective experiences exist, given that they seem irrelevant to our survival prospects, while the lovesick teenagers know perfectly well that their romantic success depends, in part, on making a credible show of aesthetic sensitivity to their own conscious pleasures.

Such evolutionary pressures to report our conscious experiences may have even influenced how we perceive and categorize things. Psychologist Jennifer Freyd has argued that some of our cognitive processes have become adapted to the demands of verbal "shareability." For example, we may tend to perceive some naturally continuous phenomena in discrete ways, just because it is easier to give verbal labels to discrete categories than to points on fuzzy continua. Applied to verbal courtship, Freyd's shareability idea suggests that sexual selection may have made human mental processes well adapted for producing romantically attractive language, not just effective survival behavior.

Gossip: Social Information,
Entertainment, or Indicator?

Apart from ourselves, we mostly talk about other people— language is mostly gossip. Evolutionary psychologist Robin Dunbar has proposed that gossip helped our ancestors to keep track of a larger number of social relationships than they could by direct observation and direct interaction. Talking proved more efficient than grooming as a way of servicing our friendships. This view of gossip as "social grooming" explains why gossip includes so many sympathy displays. The idea that gossip helps to manage large numbers of relationships clarifies why gossip sometimes sounds like a fairly methodical review of the state of every social relationship known to both speakers.

However, gossip has other features that may be better explained as status displays, and sometimes even courtship displays. Jean-Louis Dessalles has pointed out that a speaker's

utterance must seem relevant to listeners if it is to attract their attention. If language's content was shaped by the psychological biases of our ancestors, what subject matter would seem most relevant to a highly social primate? The answer, of course, is social content. If our ancestors were already spending most of their conscious lives thinking about one another, and worrying about their relationships, they would have a psychological bias to favor social content in their conversations. Gossip would fill their hunger for social information. If we had evolved from solitary spiders, our language would be as dominated by webs and flies as were our spidery minds. The social content of human speech may have no direct social function: it may simply reflect the optimal way to excite a mind already geared to social information, as a form of socially and sexually attractive entertainment. The better entertainers benefit by attracting better friends and mates. Gossip may exploit the social obsessions of the human mind as much as soap operas and romantic films do.

Yet there may be more to gossip than the passive appeal of soap operas with fictional characters. Beyond the psychological bias view of sexual selection, there is indicator theory. As with all courtship displays, we can ask what information about the displayer might be revealed in their display. To be worth listening to, gossip must be novel, but credible and interesting, which generally means that it must be new, verifiable information about mutual acquaintances. We have little interest in old information about old friends, or new information about total strangers. It is not easy to consistently produce new, verifiable information about mutual acquaintances. Since the object of gossip is a mutual acquaintance, then, all else being equal, the listener is as likely to know the news as the gossiper. If the gossiper usually knows some news that the listener does not know, the gossiper may have privileged access to secrets, or a wider social network, or a better social memory, or friends who themselves have privileged access to social information. That is, the gossiper must have high social status, and high social intelligence. This is how gossip can function as a reliable

indicator of social status and social skills. Gossip may have evolved as a status display, favored by sexual selection and other forms of social selection.

Dunbar tested his gossip theory in a 1997 paper by analyzing the content of ordinary human conversations between British adults. His results appear to support a mixture of his gossip-as-grooming theory, and my gossip-ascourtship theory. Across all conversations analyzed, social topics such as personal relationships accounted for about 55 percent of male conversation time and about 67 percent of female time. That high proportion is generally consistent with both theories. Of the time spent discussing any kind of social relationship, talking about one's own relationships accounted for 65 percent of male speech and only 42 percent of female speech. Males appeared more motivated to display the quality and number of their relationships. Also, males tend to talk more about intellectual topics such as cultural, political, or academic matters, particularly when females are present. Dunbar observed that:

Female conversations can be seen to be directed mainly towards social networking (ensuring the smooth running of a social group), whereas males' conversations are more concerned with self-promotion in what has all the characteristics of a mating lek. This is particularly striking in the two university samples where academic matters and culture/politics, respectively, suddenly become topics of intense interest to males when females are present.

For males, verbal self-advertisement appears to be a fairly constant function of speech, while for females, it may be an occasional function, more limited to one-on-one conversations with desired mates. A complete theory of the evolution of language will probably have to combine sexual selection and social selection, integrating the gossip-as-courtship theory with the gossip-asgrooming theory.

Supercalifragilisticexpialidocious

Given that the word "blue" exists, why does the word "azure" exist? They are nearly identical in meaning. It is hard to envision a situation in which natural selection would favor the hominid who could say "The sky on the other side of that mountain was azure" over one who could say "It was blue." Perhaps poetic words like "azure" were invented for some special ritual or religious function. But why then do we also need "cobalt," "sapphire," "ultramarine," "cerulean," and "indigo"?

Human vocabulary sizes seem to have rocketed out of control. The average adult human English-speaker knows 60,000 words. The average primate knows only about 5 to 20 distinct calls. The largest bird song repertoires are estimated at about a thousand, though their songs do not have distinct symbolic meanings. Unusually intelligent bonobos such as Kanzi can be taught about 200 visual symbols in ape language experiments. No other animal has a signal repertoire with distinct meanings that comes anywhere near the human vocabulary size.

In this section I look at vocabulary size as an example of how sexual selection may have shaped language evolution. If language evolved in part through sexual choice as an ornament or indicator, it should be costly, excessive, luxuriant beyond the demands of pragmatic communication. How could we measure whether language is excessive? Vocabulary is convenient to study because we can count how many words people know, whereas we do not yet know how to measure the complexity of grammar or the social strategies of conversation. More importantly, we can count how many words people would need to know for pragmatic purposes, and see whether our vocabularies are excessive.

We acquire our vocabularies with such speed that we must have evolved special adaptations for learning word meanings. To build an adult vocabulary of 60,000 words, children must learn an average of 10 to 20 words per day between the ages of 18 months and 18 years. Often these words are learned through a single exposure: an adult points to a bassoon and says "that's a bassoon" just once, and the child knows the word forever after. Human