Natural History Magazine 9/97, pages 42-45
For more than 99 percent of our evolutionary history, we lived as foragers, and our recent ancestors must have lived much as foraging tribes do today, without any of the trappings of modern civilization. Observing their seemingly simple life, many people have wondered what nonliterate foragers do with their capacity for abstract intelligence. The foragers would have better grounds for asking that question about modern couch potatoes. A foraging life is a camping trip that never ends, but one without Swiss Army knives and freeze-dried pasta.
All foraging peoples use fire and shelters and manufacture many kinds of tools. Their engineering is often ingenious, involving poisons, smokeouts, glue traps, nets, baits, snares, corrals, concealed pits and clifftops, blowguns, and bows and arrows. Animal prey may thus be flushed out, cracked open, trapped, ambushed, or done in by weapons. Plants are cut down or unearthed, shelled and skinned, and detoxified by cooking, soaking, fermenting, and other tricks of the kitchen magician.
How do they accomplish these feats? With the help of language, foragers pool their knowledge and coordinate their actions. Their words offer a window to the kinds of knowledge they possess. All documented human cultures (and by extrapolation, ancestral foraging ones) have words for space, time, motion, number, mental states, tools, flora, fauna, and weather; they make logical distinctions between general and particular, apparent and real, possible and actual. People use these words and concepts to reason about invisible entities such as disease, meteorological forces, and absent animals. They also possess knowledge that is not easily expressed in words. Their mental maps may contain thousands of noteworthy sites, and their mental calendars record cycles of weather, animal migrations, and the life histories of plants....
...A third way of knowing is intuitive engineering, the understanding of tools and other artifacts. Artifacts are defined not by their shape or constitution but by what they are intended to do. A store selling chairs might be stocked with anything from stools and dining room sets to beanbags, hammocks, and wooden cubes. A stump or elephant's foot becomes a chair if someone decides to use it as one. The only thing that chairs have in common is that someone intends them to hold up a human behind.
Tools appear in the fossil record millions of years before modern skulls do and must have been a major selection pressure for the expansion of the brains that make them. Today's one-year-old hominids tinker with sticks for pushing, strings for pulling, and supports for holding things up. Before they enter first grade, children have different intuitions about artifacts and living things. It you make a lion look like a tiger with a dye shave, children say it is not a tiger but still a lion. But if, with some snipping and gluing, you make a coffeepot look like a birdfeeder, they say it just is a birdfeeder.
No law of intuitive physics, biology, or engineering, however, can explain the actions of human beings, who clearly don't behave like rocks, animals, or wind-up dolls. To predict the deeds of others, we need intuitive pyschology - the conviction that people are driven by invisible, weightless mental states, such as beliefs and desires. We mortals can't literally read other people's minds, but we can make good guesses by listening carefully to what they say, watching their faces and eves, and trying to make sense of their behavior. Like the other core intuitions the rudiments of mind reading are first exercised in the crib. Infants make eye contact and track their parents' gaze, especially when they are uncertain why a parent is doing something. Three-year-olds show that they understand the nature of beliefs and desires and where they come fromfor example, that a looker of en wants what he is looking at, that you can't eat the memory of an apple, and that a person can tell what's in a box only by looking in it.
A child's precocious understanding of these domainspsychology, biology, physics, and engineeringsuggests that the brain is prepared for them. Indeed, some patients with brain damage cannot name living things but can name artifacts, or vice versa, implying that artifacts and living things are stored in differ ....s in.. And some kinds of mental disorders seem to impair some domains and spare others. People with autism, for example, seem to lack an intuitive psychology, whereas those with Williams syndrome are competent intuitive psychologists but are spatially and mechanically challenged.
Our mental tools are sometimes most conspicuous when we apply them in ways they were not designed for. Slapstick humor comes from a sudden shift away from thinking of a person in the usual way, as a living locus of beliefs and desires, to seeing him as a material object ignominiously obeying the laws of physics (such as slipping on a banana peel). Religious beliefs in souls, angels, and gods come from divorcing our intuitive psychology from our intuitive biology and physics so that we can think about minds that have no bodies. Animistic beliefs do the oppositethey marry intuitive psychology to intuitive biology, physics, or engineering and impute minds to trees, mountains, or idols.
And this brings us back to how our Stone Age minds grasp modern science. Formal sciences grew out of their intuitive counterparts. The conviction that living things have an essence, for example, is what impelled the first biologists to try to understand the nature of plants and animals by cutting them open and putting bits of them under a microscope. Anyone who announced he was trying to understand the nature of chairs by bringing them into a laboratory and putting bits of them under a microscope would be dismissed as mad, not given a grant.
Natural History Magazine 9/97 pages 45-47
"Socially assisted" learning is a vital part of human culture, too, but with a subtle and it turns out, crucial difference. This difference may help explain why the chimpanzee toolbox is currently limited to some modified twigs for termite fishing, rocks for bashing nuts open, and leaves to sop up water, while even a modestly equipped human household generally contains many toolsin Western culture, such things as screwdrivers, pliers, and hammers, not to mention toasters and toilet plungers.
To investigate differences in social learning in humans and chimpanzees, my colleagues and I performed experiments with human children and captive chimpanzees. In one experiment, chimps and two-year-old children watched as a human demonstrator used a rakelike tool to drag some food (usually fruit) or toys (Nerf balls or jacks, for example) closer to them. One side of the rake had several widely spaced prongs; the other was solid and flat. We divided the chimps and children into groups so that some observed an inefficient method, in which the desired object slipped through the prongs, while others watched as demonstrators flipped the rake over and dragged the object in.
Overall, humans and chimpanzees proved equally skillful at getting what they wanted with the rake. What differed was how they made use of what they had observed. The children concentrated on imitating the demonstrator's techniques, even when that meant frustration and failure as the desired object slipped through the prongs time and time again; they only flipped the rake over if they had seen the demonstrator do it. The chimps, in contrast, tended to ignore the technique of the demonstrator (whether human or chimpanzee). Once they grasped the idea that the rake could be used to move the food around, they devised their own strategy. We call this type of learning emulation because it is aimed at reproducing results, not methods.
Emulation is a perfectly good way of maintaining many cultural traditions, such as chimp termite fishing or some types of human tool use. But paradoxically, imitation is more likely to lead to the steady accumulation of newand often more complex and efficienttools, ideas, and traditions. It is this accumulation that characterizes human culture. The tendency to imitate (or at least pay close enough attention to a technique so that one could duplicate it) means that innovations made by one individual are likely to be studied closely and faithfully copied by others, who are now in a position to discover further modifications. As a result, new and improved forms have the potential to spread widely. For example, to hammer one thing into another, human beings began with stones, proceeded to stones tied onto sticks with string, and now use a range of tools from ball peen hammers to steam-driven pile drivers.