Authors: Daniel Bor
The Ravenous Brain: How the New Science of Consciousness Explains Our Insatiable Search for Meaning (37 page)
BOOK: The Ravenous Brain: How the New Science of Consciousness Explains Our Insatiable Search for Meaning
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ANIMAL CHUNKING
So far, these behavioral studies have attempted to show that other animals are conscious in some form or other, but what these experiments have largely avoided is the question of the quality of consciousness—What can these animals actually do with their awareness? One interesting question along these lines, based on the main arguments in this book, is how well other animals can use chunking strategies. Humans are certainly not the only animals that can learn in a structured way. Rats, for instance, have been shown to apply simple forms of chunking. If you present a rat with 12 hidden openings, comprising 4 sets of 3 different types of food, they will learn to group the openings together according to the food group and head straight for the 4 openings that are sources of their favorite food. Even pigeons have been shown to apply a rudimentary form of chunking in their learning. For example, Herbert Terrace trained pigeons to peck either a sequence of colors or a mix of colors and plain white shapes. In order to obtain food, the pigeon had to get the entire sequence right. The pigeons were painstakingly trained for up to 120 sessions to get a sequence of 5 in a row correct in order to get food—probably the equivalent human task of completing a degree. The pigeons struggled terribly if the sequence was all 5 colors, but they did far better if they could break the sequence down into 2—for instance, if the first 3 were colors and the last 2 were shapes. It wasn’t just that there were 2 different kinds of stimuli to remember: If the colors were interspersed with shapes—for instance, a shape, then a color, then a shape, then a color, and finally a shape again—then the pigeons were back to being terrible at the task. This grouping of parts of a sequence could well be analogous to human forms of chunking.
But there is a world of difference between being able to chunk at all, on the one hand, and being able to discover and use chunks in a powerful, hierarchical way, on the other. Other animals may be able to recognize themselves in a mirror, plan for future events, remember many past ones, or even be aware of their own awareness, but one key factor where humans—even toddlers—leave animals in the shade is the extent of our ability to chunk. Specifically, it seems that the number of levels of chunking on which we can operate, the height of our pyramid of meaning, easily outstrips even our closest relative, the chimpanzee.
One way of demonstrating this is to observe different species at play. In one experiment, a group of chimps from 15 months to adulthood, one adolescent bonobo, and human babies between 6 months and 2 years of age were all given a random collection of 6 objects, such as cups, rings, and sticks that could be red, blue, or yellow. The experimenters simply watched them play and recorded how they moved the objects about, combined them, and so on. Various levels of information and behavior are available here: On a basic level, these are all separate objects and can be manipulated one at a time. But far more meaning than this can potentially be extracted. For instance, the objects can be grouped by type, size, or color alone, but two categories can also be combined—for instance, by placing all the red rings together. A higher level still is even available, if all the large red rings, say, are separated from their smaller equivalent. Then there are the relations between different items. For instance, sticks and rings can be placed
inside
cups, and sticks can pass
through
rings.
inside
cups, and sticks can pass
through
rings.
When it comes to the basic skills of manipulating single objects, there is little to separate human babies from their primate cousins of the same age. As soon as you move up the information pyramid, though, developmental differences become increasingly apparent. Chimps and bonobos can learn to group items according to categories, such as color or shape, but they learn such concepts considerably later than humans do, and the complexity, or levels, of meaning they can learn are terribly limited compared to human babies. It is not uncommon, for instance, for a human baby, by the age of two, to use one hand to turn upright and then hold a cup, and use her second hand to clasp a few small spoons together out of a set of random cutlery, which includes larger spoons, forks, and so on, before finally placing the small spoons in the cup. By grouping the small spoons together, she is demonstrating at least two conceptual levels above individual items because she is picking objects based on two combined categorical features. She is then demonstrating knowledge of another level again when she puts the spoons in the cup, by linking a group with another item. These seemingly simple acts appear largely beyond any other primate, at any stage of development. But, of course, humans rapidly learn far more complex, hierarchical concepts and actions than this relatively straightforward example.
In a more formal series of experiments exploring this issue, humans between the ages of 11 and 36 months and mature chimpanzees, bonobos, and capuchin monkeys were all compared on the same simple task. All subjects were given three nesting cups, a standard children’s toy (see
Figure 7
). The experimenter repeatedly demonstrated what was required of the subjects: To place the smallest cup inside the middle cup, and then put both cups together inside the largest one. The cups were then dismantled and the subjects were encouraged to copy the experimenter exactly. This is a useful developmental test for human babies. When they are around a year old, all that most children can do is place one of the three cups inside another, leaving the third untouched—in other words, they can’t complete the task. By around 16 months, they can complete the task, putting the middle cup inside the large one and then the smaller one inside the other two. This isn’t quite what the experimenter showed them. Critically, these toddlers haven’t yet grasped the complex, hierarchical idea that you can move two cups at once (the middle one with the smaller one inside), as if they were a single compound item, and in addition that this group of cups can still be placed in any cup larger than the outside one. (I’ve watched my daughter at this age play with the same kind of toy, and even if I place the smallest cup inside the middle one to help her to solve the puzzle, she will deliberately take the smallest cup out before stacking the cups one by one [middle into largest and then smallest into middle]. For her, it seems as if the concept of groups of nesting cups is seemingly impossible. The group simply has to be dismantled for progress to be made.) Finally, many children from around the age of 20 months or so can exactly copy the experimenter. This shows that they have grasped the idea of hierarchies, so that two objects put together can in some sense be seen as one single object.
27
You might suspect that part of their mastery of this progression arises simply from infants and toddlers having ample time outside of the lab to know how to manipulate these or similar items. But although that’s true of most babies in Western culture, this and a related experiment were also carried out in Zinacantecos babies and toddlers in southern Mexico, and they also exhibited mastery of hierarchy. This Mayan group has few materials in its environment on which to practice these kinds of manipulations, and the children have no toys, but the Zinacantecos children showed exactly the same pattern of development, suggesting that this stepwise acquisition of the mental machinery of hierarchical chunking is universal.
Figure 7
). The experimenter repeatedly demonstrated what was required of the subjects: To place the smallest cup inside the middle cup, and then put both cups together inside the largest one. The cups were then dismantled and the subjects were encouraged to copy the experimenter exactly. This is a useful developmental test for human babies. When they are around a year old, all that most children can do is place one of the three cups inside another, leaving the third untouched—in other words, they can’t complete the task. By around 16 months, they can complete the task, putting the middle cup inside the large one and then the smaller one inside the other two. This isn’t quite what the experimenter showed them. Critically, these toddlers haven’t yet grasped the complex, hierarchical idea that you can move two cups at once (the middle one with the smaller one inside), as if they were a single compound item, and in addition that this group of cups can still be placed in any cup larger than the outside one. (I’ve watched my daughter at this age play with the same kind of toy, and even if I place the smallest cup inside the middle one to help her to solve the puzzle, she will deliberately take the smallest cup out before stacking the cups one by one [middle into largest and then smallest into middle]. For her, it seems as if the concept of groups of nesting cups is seemingly impossible. The group simply has to be dismantled for progress to be made.) Finally, many children from around the age of 20 months or so can exactly copy the experimenter. This shows that they have grasped the idea of hierarchies, so that two objects put together can in some sense be seen as one single object.
27
You might suspect that part of their mastery of this progression arises simply from infants and toddlers having ample time outside of the lab to know how to manipulate these or similar items. But although that’s true of most babies in Western culture, this and a related experiment were also carried out in Zinacantecos babies and toddlers in southern Mexico, and they also exhibited mastery of hierarchy. This Mayan group has few materials in its environment on which to practice these kinds of manipulations, and the children have no toys, but the Zinacantecos children showed exactly the same pattern of development, suggesting that this stepwise acquisition of the mental machinery of hierarchical chunking is universal.
What happens when the chimps, bonobos, and monkeys try this task? Much of the time, even with extra, guided training, they only reach the first developmental stage that the children reach. A minority of the bonobos can at least reach the intermediate, nonhierarchical stage of stacking all three cups correctly, like the human sixteen-month-olds. But virtually none of the animals can grasp the idea of combining two objects together and then moving them, even though the experimenter had just that moment shown them exactly this.
Therefore, young children can outperform adult chimps, bonobos, and monkeys on tasks requiring that they chunk in this hierarchical way. Although these other animals may well be highly conscious, the exceptional richness of human awareness may critically be reflected in our superior ability to find and combine structured information.
Of course, stacking cups, while surprisingly complex, is nevertheless one of the simplest tasks human children perform. As children grow up, the toys they play with rely on an increasing number of levels of meaning as well as more sophisticated relationships between items. And each stage of human play reflects the widening gap in cognition and consciousness between children and primates of the same age.
I described in Chapter 5 how there is nothing exceptional in the quantity of items humans can place in consciousness: Humans, like a wide variety of other species, are limited to only three or four working memory objects. However, human consciousness is so rich, so powerful, because of the extent to which we can manipulate and combine this handful of online items, especially in hierarchical ways. The above experiments demonstrate how this seemingly trivial difference between humans and other species starts conceptually to explode after only a couple of years of life.
INFANT AWARENESSDoes this mean that human infants aren’t conscious until they are around twenty months old and are able hierarchically to combine objects and actions together? Almost certainly not. This milestone merely signifies that a critical stage in a growing consciousness has been reached—a stage where experiences will be far more varied and complex, and where learning can skyrocket.
When, then, do the first seeds of infant awareness start reaching up from the soft soil? Does this occur before birth? A fetus can be remarkably active, kicking and punching away on a regular basis, from surprisingly early in pregnancy—usually by about seven or eight weeks, although the mother won’t feel these movements until a few months later, when the fetus has sufficiently grown. Toward the end of pregnancy, the fetus can also be highly responsive to the outside world, either via pressure on the uterus or muffled sounds filtering in from outside. Does all this signify consciousness? This is unlikely, because both the mother’s placenta and the fetus itself work actively and in concert to keep the fetus under safe sedation while inside the uterus. Effectively, the fetus lives its prebirth existence in a kind of dream state—though with few stimuli so far absorbed, such dreams would be unlike ours, with little, if any, detail. Instead, the fetus only really wakes up in the sudden, shocking moment of birth.
Is this the moment of first consciousness? This is where the behavioral approach fails us, as there are few clues early on that clearly demonstrate awareness. My personal intuition, from watching my own baby daughter develop, is that you can’t help assuming that there is a strong sense of awareness from soon after birth. If consciousness cares about novelty and unexpected events, then my daughter’s profound surprise for much of her first two months whenever she developed the strange sensation of hiccups is one intriguing piece of evidence in support of early consciousness. Then, just shy of her third month, she started laughing at my silly antics. Admittedly, with little science to back this up, I felt that this humorous reaction was the signature sound of conscious surprise, and it gave me little doubt that my daughter was indeed now aware of the world.
Still, another approach that ignores behavior entirely might provide more definitive answers to such questions where they otherwise cannot be found.
MEASURING CONSCIOUSNESS IN ANIMAL BRAINSAssessing consciousness in other beings via these roundabout behavioral measures is a fascinating thing to do, but there are problems with this approach. The first, which I have already mentioned, is that it is difficult to interpret a positive result. Because the animal cannot tell you that it is conscious, any pass in a test has to be taken with caution as to its implications for the exact nature of the animal’s inner mental world. This is more readily true in artificial intelligence, where a robot could be programmed to pass any of the tests I mentioned above, from the mirror-recognition test to the gambling tasks. This signifies very little. The robot would probably fail any other task of awareness, passing only the one it was programmed for, and of course a few lines of code does not equal consciousness.
The second problem is that we cannot rely on a negative result in these tests either. In the novel
The Girl with the Dragon Tattoo
by Stieg Larsson, the title character, Lisbeth Salander, is quite a wild child. The teachers and authorities investigate her unruly behavior by subjecting her to every psychological and educational test in the book, but her response is to refuse even to lift up her pencil to write her name. Because she effectively fails each of these tests, the authorities assume with surprising dogmatism that she must therefore be mentally retarded, and she is consequently officially classed as such well into adulthood. The truth, it increasingly transpires, is that she is in fact fiercely intelligent, and she is quite capable, when the need arises, of twisting these prominent authority figures around her highly independent finger. What the authorities should have understood when testing this girl was that if someone fails a test, an inability to carry out the required attribute is only one of a range of possible explanations.
The Girl with the Dragon Tattoo
by Stieg Larsson, the title character, Lisbeth Salander, is quite a wild child. The teachers and authorities investigate her unruly behavior by subjecting her to every psychological and educational test in the book, but her response is to refuse even to lift up her pencil to write her name. Because she effectively fails each of these tests, the authorities assume with surprising dogmatism that she must therefore be mentally retarded, and she is consequently officially classed as such well into adulthood. The truth, it increasingly transpires, is that she is in fact fiercely intelligent, and she is quite capable, when the need arises, of twisting these prominent authority figures around her highly independent finger. What the authorities should have understood when testing this girl was that if someone fails a test, an inability to carry out the required attribute is only one of a range of possible explanations.
Similarly, if an animal is not interested in playing along, you have no way of knowing if it is capable of passing the test. Maybe it could easily pass it, but stubbornly refuses to try. In other words, as with so many tests in psychology, a negative result simply cannot be interpreted as an inability of the animal to perform a given skill. Another problem with the behavioral approach is that there is no clear way to gauge
how
conscious an animal is. Only a few very distinct stages are explored, and there is little scope for a continuum of conscious level, which is probably a more appealing idea than the more ugly assumption that you either have consciousness or you don’t.
how
conscious an animal is. Only a few very distinct stages are explored, and there is little scope for a continuum of conscious level, which is probably a more appealing idea than the more ugly assumption that you either have consciousness or you don’t.
BOOK: The Ravenous Brain: How the New Science of Consciousness Explains Our Insatiable Search for Meaning
5.04Mb size Format: txt, pdf, ePub
ads
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