Human development of mental scenario building explodes after age two, however, while great apes’ capacities do not. Children spend a considerable amount of their waking life in fantasy play. They conjure up and untiringly repeat scenarios with props such as dolls and toys. Thinking, in a fundamental way, is imagining actions and perceptions, and it has been argued that in play children test hypotheses, consider probabilities, and make causal inferences not entirely unlike (adult) scientists. Play certainly provides opportunity to practice, to build up expectations, and to test them. Children take on roles and act out narratives of what happens in certain situations. Gradually, they learn to deliberately imagine scenarios and their consequences without having to act them out. They learn to simulate mentally. They learn to think.
Eventually, children can imagine an almost limitless array of events. They begin to deploy counterfactual reasoning in which they contrast what did happen with scenarios of what did not happen. They increasingly consider what might happen in the future. A key to our open-ended, generative capacity is our ability to recursively embed one thing in another, as it enables us to combine and recombine basic elements such as people, objects, and actions into novel scenarios. Such nesting is also essential for reflection: our capacity to think about our own thinking. Nested thinking allows us to reason about the mental scenarios we entertain (just as we can draw pictures of ourselves drawing a picture).
We can connect diverse scenarios into larger plots. Narratives provide us with explanations for why things are the way they are and with opportunities for prediction or scheming how they will be. We can reflect on the relationships between past experiences and construct complex plans with embedded if-then steps. Even our closest animal relatives have not demonstrated this open-ended nesting ability. One explanation for this lack is that they do not have the necessary working memory capacity to embed information recursively. Michael Corballis has championed the idea that recursion is uniquely human. We came across evidence for this repeatedly, and it is easy to see its relevance in other contexts such as architecture, cooking, and music. You can apply your own recursive thought to come up with more domains.
Children also learn how thought can control action. For nested scenario building to provide adaptive advantages, one needs to gain some executive control, for instance, to inhibit present desires in the name of more prudent long-term goals. More generally, natural selection could not have gotten its teeth into private daydreaming; our scenario building must have had outward consequences for survival and reproduction. Our minds matter. Crucial here is the audience of our mental plays, to stick with the theater metaphor. The neurobiologist Bernard Baars suggests that consciousness is a broadcasting system: it disseminates single momentary messages throughout the brain to achieve coordination and control. The information we are aware of is made available to all subsystems.1 Consciousness provides cohesion and allows a complex nervous system to pull in one direction. Conscious simulation of scenarios may therefore allow us to pursue complex plans. As long as we can manage our more immediate urges, our mental simulations and reflections can gain control over actions. To a significant extent, we can become masters of our own destiny.
Individual simulation is flexible and powerful but also a risky way of making decisions that can lead us fatally astray. In the heat of Australia’s north a river may appear inviting for a swim—until you note the sign about the crocodiles. Individually, we often miscalculate, harbor false expectations, and become confused as to which option to pursue. Nested mental scenario building is not a crystal ball, nor is it a logical supercomputer. For flexible scenario building to really take off as the ultimate survival strategy, it required a second leg to stand on.
Our ancestors discovered that they could dramatically improve the accuracy of their mental scenarios by increasingly connecting their minds to others. We give each other advice—for instance, by posting signs about the possible presence of crocodiles. We can broadcast our imaginary play not only throughout our own system but to others around us. We exchange our ideas and give feedback. We ask others, and we inform them—for instance, by recounting what it was like when we were in a similar situation. We take an interest even without knowing whether anything important or useful comes of it. There are individual differences in how much an interest people display in what certain others have to say, but we are generally driven to wire our minds to those around us. Our expectations and plans are subsequently a lot better than they could have been if we didn’t listen. It is generally good advice to consider advice—preferably from a variety of sources—before making up your own mind.
We saw that nested scenario builders can benefit from cooperating with other scenario builders in many other ways. For instance, our audience can be recruited for common goals. We can hatch complex plans, divide labor, and pledge cooperation. We can accumulate our achievements and pass them on to the next generation. To ensure all this happens, we appear to be hardwired with an insatiable urge to connect our minds.
Primates are social creatures, and evidence that social pressures have driven the evolution of primate intelligence is mounting. Humans have taken this sociality to another level. Unlike other primates, children sob to attract attention and sympathy. We ask what’s wrong and try to make things better. We look each other in the eye, share what’s on our minds, and absorb what is on the other’s. This urge to connect must have been crucial to the establishment of signs and words that allow us to effectively read others’ minds and express our own. We are driven to wire our mental scenario builders into large systems of scenario builders. We can learn from others’ experience, even second- or thirdhand. Our drive ultimately led to today’s networks of mobile phones and social media that let us exchange our minds across the globe.
As Michael Tomasello and colleagues have demonstrated, we make and pursue shared goals where our closest relatives do not. Even two-year-old children outperform great apes on tasks of social learning, communication, and intention reading. Other animals may give alarm calls and food calls but otherwise do not show many signs of a drive to share their experience and knowledge with others. Again, in all six domains this cooperative drive is evident and plays a significant role. Language is the primary means by which we exchange our minds. We talk to each other about the past and make plans about the future. We read and tell each other what is on our minds. We reason and solve problems collectively. We build social narratives that explain the world around us. We teach, and we learn from each other. And we argue about what is right and what is wrong. These examples serve to remind us how pervasive the urge to connect is. Those who lack this drive have severe social difficulties (and may be diagnosed as autistic). Our urge to connect was essential for the creation of cumulative cultures that shape our minds and endow us with our awesome powers.
Our capacity for nested scenario building even allows us, drawing on past experiences, to imagine others’ advice internally.2 So you might ask yourself what your mother would have said about the situation you find yourself in. We care about whether our parents, friends, heroes, or gods would be proud of what we do, even if they no longer exist (or never did). We can consider what others might remember us for. These thoughts can be important drivers motivating us to go beyond satisfying immediate personal self-interests in pursuit of “higher” notions of honor, valor, and glory.
We might aspire to nobility in character and virtue in action. We can invest heavily in unselfish actions, such as fighting oppression or pollution or helping a club, a person, or an animal. When we take on a cause, we seem to become part of something bigger and from such endeavors may derive some of the deepest feeling of meaning. One of the most remarkable things about humans is that we can strive to make some kind of difference. We may deliberately practice random acts of kindness, spread the word, fight injustice, teach the next generation, or start a revolution. Without the urge to connect our minds, such traits could not exist.
In sum, nested scenario building and t
he drive to link our scenario-building minds turned ape qualities into human qualities. They created powerful feedback loops that dynamically changed much of the human condition. They carried us where other animals could not go.
THE GAP, THEN, MAY IN one sense be much smaller than we might have anticipated. Only a couple of basic differences appear to have evolved between ape and human over the last six million years. In another sense, the gap clearly is vast. The two qualities represent profound differences that have had countless cognitive, emotional, and motivational consequences.
Children’s play shows how the two legs work in lockstep to open dramatic new possibilities. Children often play together by acting out imaginary scenarios. They coordinate roles, such as doctor and patient, and play out how events might unfold. These social constructions teach children about particular situations and how to negotiate their scenario-building minds. Children learn from each other through imitation and instruction, adopting and enforcing socially inherited rules. They love playing games. They usually are desperate to win, even if no concrete rewards are involved.
We already saw how play gives children opportunities to practice thinking. They begin to select skills they want to get better at, typically with encouragement from their parents, and playfully rehearse. As we saw in Chapter 5, our scenario-building minds even allow us to practice just mentally rather than physically, and we can improve as a result. We provide our own feedback, or imagine the feedback we think others might give, without actual reward or punishment. Our capacity to create future scenarios and to consult others with expertise allows us to gradually become experts in our own right. Much of the human diversity of expertise is a function of the fact that different people expend effort in learning and perfecting particular skills. Just think of the Olympics. Even within each area of expertise we differ vastly from each other. Each of us is unique. Our extensive cooperation and division of labor means that groups, and the individuals within it, benefit less from everyone being good at the same thing than from being good at a host of complementary skills. Groups composed of individuals with high polyvalence may have had a particular advantage. Perhaps we have evolved to be so individually different because our species is extraordinarily social and cooperative.
In addition to play, children love stories. Stories contain lessons learned by others, and even entirely fictional narratives give the listener potentially useful information. Most stories involve a hero overcoming obstacles and enable listeners to learn how to solve problems—and what virtues are worth pursuing. In short, stories allow us to acquire experiences without having to leave the house or risking life and limb. The desire to listen to stories, to be entertained by them, is therefore a powerful facilitator of cultural transmission.
These days we can watch or listen to stories anytime, anywhere, at the press of a button. Virtual theaters beam other people’s scenarios into our minds at extraordinary rates. Although we may enjoy such narratives alone, the sharing of stories used to be entirely social events. At a minimum one person shows or tells another. When stories are told to an audience of several people, everyone tunes in to one and the same scenario. Members of the audience have similar thoughts, emotions, and learning experiences. Stories, whether told or enacted, thereby help synchronize values, moral norms, and expectations in the group. Human cultures and belief systems are to a large extent defined by their stories. Stories of ancestors and origins shape our social identity: who we are and where we come from. Stories provide meaning and explanation.3 Stories create bonds between people.
Whereas chimpanzees groom each other to bond and keep the peace, human cultural groups bond through sharing mental experiences. People gather at festivals to reaffirm their cultural identity through rituals and celebrations. They wear specific clothes, engage in traditional ceremonies, perform and act, tell stories of legends and ancestors. We sing and dance together, and we enjoy watching others perform. We hold concerts, parades, and shows. We celebrate birthdays and weddings, commemorations, and seasons. Animals do not appear to care about any of this. Contrary to how animals are depicted in children’s cartoons, such as the film Madagascar 2, they do not seem to like to party.
Interestingly, humans who entertain others tend to have a sexual selection advantage. Artists, actors, and musicians typically have more partners than less entertaining types. Such a benefit is a powerful incentive for engaging in creative endeavors. As with other expertise, to improve their capacities entertainers practice their performances. And as we do with mental scenarios, tools, or sentences, we combine and recombine basic elements to create novel entertainment in acts, dance, and music.
Moreover, in many cultures, entertainment, parties, and ceremonies are fueled by mind-altering substances or practices, such as meditation or hypnotically repetitive dance. Psychoactive drugs, in particular alcohol (though the list spans all the way from coffee to cocaine), are powerful lubricants in many social exchanges. Animals have the capacity to form drug addictions—which is why they are often used in drug research—but drugs play a peculiar role in human societies. Sages, oracles, witches, and shamans have long used drugs for the express purpose of expanding their minds in quests for wisdom and access to worlds of spirits, gods, and fortunes. We know little about how far back such activities go, nor how much of a lasting influence they have had on the evolution of our minds. Obviously some drugs are dangerous and can lead to all sorts of problems. Nonetheless, many people go to great lengths and are willing to take great risks to manipulate their mental states through drugs. Whether socially sanctioned or not, our stories, rituals, and entertainers are full of them.
The difference between human and ape is clearly not only intellectual or rational in nature. Our scenario-building and -sharing capacities are also essential for our desire to let go of our worries and indulge in intoxication, celebration, passion, and excess. These facets of the human mind drive some of our most peculiar behavior. In ancient Greek mythology Zeus’s son Dionysus represented these tendencies, whereas Apollo stood for harmony, order, and reason. The struggle between such opposites is a topic of much of our popular culture, from the fights between the Freudian id and the superego to those between Dr. McCoy and Spock. Trying to balance these forces is the decision-making ego, or Captain Kirk if you prefer. Our mind is a complex beast, and I won’t pretend to be able to do all of it justice here. I have tried to focus on the basics that separate our minds from those of our closest animal relatives.
Our interconnected scenario-building minds have created virtual worlds of kaleidoscopic variety. Together we agree on shared immaterial ideas, ideals, and other make-believe. For instance, we invent social roles, institutions, and symbols, which we collectively imbue with specific authorities and powers. Referees, idols, CEOs, officers, priests, banks, and national symbols serve important functions in our communities and are critical for regulating our extremely complicated webs of cooperation. But their reputations, powers, and responsibilities only exist in our collective minds. Animals cannot perceive them. We merely imagine them together and act as if they are real. And so, for us, they are.
We have evolved a cultural world. Our collectively imagined ideas and concepts shape the very fabric of our reality. As children grow up, they face selection pressures within this artificial environment. Human cultural evolution and the evolution of human minds are inextricably intertwined. We shape the environment in which our children develop, what they learn, what they value and believe. Biologically oriented scientists sometimes underestimate the power of socialization and culture.4 We should not. To a large extent we socially construct our minds. It is easy to see why one may be tempted to conclude that the gap, then, is the result of our cultural nurturing of growing minds. However, it is also the case that no amount of this same socialization can turn a goldfish, cat, or horse mind into a human mind, so far as we know. There is some evidence that great apes raised by humans, and so “enculturated,” perform slightly better than their kin in the zoo on a f
ew measures.5 Still, we cannot turn them into anything like the reflective chimpanzee Kafka imagined. Humans are uniquely prepared to cross the gap and acquire our cultures. Therefore, I conclude with a discussion of how we appear to be biologically adapted to the cultural world our ancestors created.
No other animal passes so large a portion of its existence in a state of absolute helplessness, or falls in old age into such protracted and lamentable imbecility.
—JOHN HERSCHEL
OUR PREPAREDNESS FOR CULTURE COMES at a price. As Herschel observed, humans are extraordinarily weak and dependent in infancy and often also in old age. A newborn human must indeed be one of the most defenseless beings on the planet: it takes many weeks before it can even hold up its head and a year for it to walk. Yet brain growth outside the womb is crucial for our mental plasticity and hence our capacity to inherit culture from our social environment. Human brains grow more outside the womb than their closest relatives’ brains do—both in absolute terms as well as proportionally (human newborns have only about 28 percent of their adult brain size, whereas chimpanzee newborns have an average of some 40 percent).
Stephen Jay Gould has argued that humans, in a sense, avoid growing up altogether. We continue to learn and remain playful and curious into old age—characteristics that for most mammals are found only in the young. The retention of juvenile traits into adulthood is called neoteny. And it is a great trick that with a few genetic changes can bring about vast consequences. Consider the axolotl, or Mexican walking fish. This common inhabitant of many aquaria has legs, can walk, and looks most peculiar for a fish. The reason for this is that it is not a fish at all but a neotenous amphibian. It is a salamander that has failed to grow up, remaining in the larvae stage without undergoing the metamorphosis into an adult. The flat face of a chimpanzee infant resembles that of a human. However, as they grow up, chimpanzees look ever less like us. Perhaps Gould was right when he argued we are a neotenous ape.
The Gap Page 27
