Object permanence
Marc Hauser uses the metaphor of an inborn mental toolkit, part of which is “a basic set of principles for recognizing objects and predicting their behavior.” Many of these principles, such as object permanence and size constancy, were first identified by Jean Piaget, a pioneering developmental psychologist who described the intellectual stages human babies pass through.
Object permanence is the notion that things continue to exist even if you can’t see them. If you take attractive food and show it to an animal and then, while it watches, put it under a cup, does the animal still think it’s there under the cup, or has it ceased to exist?
In Irene Pepperberg’s laboratory, they looked at object permanence with African grey parrots. By the time Griffin was 33 weeks old, his food preferences were clear. He was not wild about pellets of bird chow, but he loved cashews.* Under Griffin’s watchful gray eyes, Pepperberg took a cashew, put it under a box, moved the box behind a screen, and then moved the box out again. Allowed to investigate, Griffin looked under the box, found no cashew, and accordingly checked behind the screen, where he found a cashew, which he ate. Pepperberg repeated this test, but this time secretly substituted a pellet of bird chow for the cashew. When Griffin looked behind the screen and found a pellet instead of a cashew, he stared at the pellet. He overturned every box in sight. He ran to Pepperberg in distress. The object wasn’t permanent!
They tried this on Alex, who was older and more familiar with tests. “After upending the box and finding a pellet, Alex turned from the apparatus to the experimenters, narrowing his eyes to slits, a behavior we have come to interpret as ‘anger.’” They gave him a trial in which the cashew stayed a cashew and then once again substituted bird chow. This time, in addition to giving Pepperberg the nasty slit-eyed look, he banged on the table with his beak. I suggest that Alex has learned that if things are weird, it’s Irene’s fault.
I can see it, but I can’t get my hands on it
Psychologist Adele Diamond worked with human babies to find out at what age they could inhibit one action in favor of another. She presented them with a clear plastic box containing an enchanting toy. The box was only open on one side. If the open side faced the babies, they could reach in and grab the toy, but if the open side was on the far side, they had to reach around to get it. Babies under nine months old could not figure this out and kept reaching straight ahead. “Like insects and birds banging into windows, they appeared to have in mind a simple yet rigidly fixed rule for reaching: if a desired object is in front of you, reach straight ahead,” writes Marc Hauser.
Baby rhesus monkeys start out baffled, too, and can’t comprehend reaching around until they’re over four months old.* In Hauser’s lab, they tried the clear box test on adult cotton-topped tamarins, who failed miserably, to the researchers’ surprise. They tried again, with an opaque box. The tamarins knew that the food was there, even though they couldn’t see it. But because they couldn’t see it, the powerful impulse to reach straight ahead didn’t kick in, and they could reach around to the side and get the food. In a clever follow-up, they gave the tamarins who had solved the opaque-box puzzle the same task with a clear box, and this time they passed. “Having learned about alternative reaching responses with the opaque box, the tamarins applied their knowledge to the transparent box. Moreover, they inhibited a seemingly potent tendency to reach straight ahead for food lying directly in front of them.”
Psychologist Margaret Redshaw compared “4 hand-reared, lowland gorilla infants…resident in Jersey Zoo, and 2 mother-reared, male human infants, resident in London” for the first 18 months of their lives, looking at their achievement of the various Piagetian stages of the sensorimotor period. They passed through stages in the same order, but in general the gorilla babies started sooner and finished sooner. During the first year the little gorillas were 4 to 16 weeks ahead of the little humans. For example, being able to get a toy that is too far to reach by pulling on a cloth the toy is resting on is something that the gorillas could do at 18 to 30 weeks and people couldn’t do until 34 weeks.
Before you go trading your kid for a gorilla, the gorillas later showed some ghastly deficits, such as (1) not making towers of two blocks and (2) not learning English. Also, “only one gorilla placed a wheeled toy on an incline, while the other ran away with the experimental apparatus.” After the first year their behavior becomes more divergent. Redshaw writes, “The human infant learns to talk, play symbolically and to walk bipedally, while the gorilla knuckle-walks, chest-beats, wrestles, climbs and builds nests.” The one thing on which gorilla and human babies were perfectly synchronized was the systematic dropping of objects, which enchanted both species from 34 weeks on.
Numbers and nature
In addition to checking animals for vocabulary and grammar abilities, it’s also possible to look at their math apititude. Researchers have looked at whether apes, in particular, can display numerousness, ordination, counting, and subitization. Numerousness is the ability to judge quantities—a little, a lot, more. Ordination is putting things in a linear sequence. Some people think counting is the most sophisticated of these abilities, and others vote for subitization, the ability to rapidly label small quantities of things, usually fewer than six.
Sarah, Sheba, and the gumdrops
Sarah Boysen, looking at the numerical skills of chimpanzees, set up a task situation for two apes, Sarah and Sheba. Previous experiments had left Boysen marveling at their grasp of number concepts. She was now looking at their ability to make quantitative judgments. In such tasks animals usually are asked to point to the larger of two groups of items (here, gumdrops), which they then get as a reward. Instead, Boysen set out the task of pointing to the one of two groups of items which would be given to the other chimpanzee. Since Sarah and Sheba liked gumdrops and weren’t particularly generous, they should have pointed to the dish with less candy. Then the other chimp would get the smaller amount and they would get the larger amount.
Neither chimpanzee could do it. Time after time the chimpanzee would point to the dish that held more gumdrops, and then, to their obvious frustration and distress, watch as it was given to the other chimpanzee. They would cry out in dismay and strike the apparatus. They simply could not learn to point to the smaller amount of candy. Like the tamarins, or babies under nine months, they couldn’t inhibit the impulse to reach toward what they wanted.
Sheba had been taught Arabic numerals up to 6, and Boysen now tested to see if Sheba could indicate the smaller of two numerals, printed on cards, to decide how many gumdrops would be given to Sarah. Here Sheba had no difficulty. If the numbers were 2 and 6, she would point to the 2 and watch as two gumdrops were given to Sarah and then six gumdrops were given to her. But when they went back to pointing at actual candy, Sheba’s performance fell apart. She understood the problem. She could do it with abstract numbers. But when she saw gumdrops, passion trumped reason.
Robert Shumaker repeated this experiment with Azy and Indah, orangutans at the National Zoo. Since they had not been taught Arabic numerals, and since zoos disapprove of gumdrops, he used grapes. At first they didn’t know what Shumaker wanted. Azy just pointed to whichever bowl of grapes was on the right. This strategy resulted in Azy getting the larger amount of grapes only about 40 percent of the time. Then his performance suddenly jumped, and he was getting the larger amount almost 100 percent of the time. The jump happened overnight, Shumaker notes. “The only way I can explain it is that he was thinking about it overnight in his nest.” Indah’s performance went to 95 percent. The orangutans could do what the chimpanzees could not.
Shumaker does not argue that orangutans are smarter than chimpanzees, but that they are less impulsive. Chimps, who are intensely social, may have been selected for impulsive food grabbing. If they don’t instantly snatch the biggest portion, another chimp will. Orangutans, who are far more solitary, can sit and ponder what to eat without worrying about another ape grabbing it. Thus social d
ifference can lead to cognitive differences—or to apparent cognitive differences.
Another way to think of social-cognitive differences is in terms of personality. Primatologist Junichiro Itani was a pioneer in the study of animal personality (a subject only beginning to be considered respectable in English-language animal behavior research). Itani proposed that there is more variation in personality in primate groups as they become more complex. As P. J. Asquith summarizes, “In prosimians, the individual variability is very small. In Japanese macaques it becomes wider, in Pan [chimpanzee species] even wider, and in man the individuality is even larger.” Curiously, recent studies show wide personality variation in octopuses.
Attempts to persuade a raccoon to reveal whether it could tell an array of three objects from arrays of one, two, four, or five objects were impeded by raccoon personality. Although at the beginning the raccoon was delighted to open a Plexiglas box and extract three grapes, Rocky soon became bored with grapes and would only play for raisins. Then he held out for chocolate-covered raisins, and then he demanded little metal bells. When he correctly opened the box with three bells in it, he was allowed to play with them, which involved batting and chasing them, and washing them in water. Rocky eventually paid enough attention often enough for the experimenter to conclude that Rocky was reliably selecting the number 3, whether through counting or subitizing. In the report the experimenter wonders why more people don’t do research with raccoons, despite their reputation of being problem solvers “perhaps to a fault,” and concludes that it has to do with lack of docility rather than lack of brainpower. “Rocky’s attention span was less than ideal, and he became extremely difficult to manage during the early spring, when more salient motivational states than ‘concern with number’ were aroused.”
Cognitive maps
Another area in cognitive research is the mental map. While the ability to form a cognitive map of the world around you may be innate, the actual details must be learned. Constellations, magnetic fields, the scent of water currents, the position of the sun, and other things some animals are predisposed to notice must be aligned with individual landmarks if the animal is to be able to find its way around when it grows up.
Frillfin gobies often live in tide pools. If, at low tide, you try to net, grab, or otherwise irk a frillfin goby that appears to be trapped in its small pool, the goby will simply leap out of the pool into the next pool and, as you follow, will by a series of up to six jumps bound, by a zigzag path if necessary, to open water. It seems that a goby learns the topography of the area at high tide, and maps it mentally, so at low tide it can calculate where to leap so that it lands in the next pool and not on the rocks or in your jaws.
Classic experiments with indigo buntings who grew up in a planetarium showed that while in the nest, the baby buntings learned to know the stars, and used them to orient themselves later when they migrated. They didn’t need to see the whole sky, just a patch.* If biologist Steve Emlen showed them the wrong constellations in their youth, they would try to migrate in the wrong direction as adults. They learn this during a sensitive period. “Importantly…the way a bunting acquires song and the way it acquires spatial knowledge are different, involving different brain structures and developmental timetables,” writes Marc Hauser. “If the organism depended on a domain-general learning system, one that was blind to the kind of experience or knowledge to be acquired, it would often learn the wrong things, or learn the right things too slowly, and thus decrease its chances of surviving.”
The inquiring mind
While it is possible to be curious and stupid, curiosity is linked to knowledge, in that curiosity drives learning. An incurious animal won’t learn much. Stephen Glickman and Richard Sroges did a classic study of curiosity by presenting objects to zoo animals and analyzing their reactions. The study was done in the 1960s, when enrichment was not a popular concept among zookeepers, and the introduction of blocks of wood, dowels, pieces of rubber tubing or chain, or a crumpled ball of paper was an earthshaking event for most zoo denizens. Some were too frightened to go near the objects. Some attacked the objects. A few found them erotic.
Lemurs sniffed the objects, rodents chewed on them, colobus monkeys surveyed them from a distance, baboons handled them extensively, and the big cats caught and subdued them like prey. The baboons and the cats were particularly averse to having the objects removed, and in the case of the baboons, a fire hose had to be used. A wily chacma baboon was up to this challenge, and as soon as the hose was directed into the cage would rush to the front and divert the water with “a well-placed forepaw.”
Reptiles did not care about the objects, except for a rather manic Orinoco crocodile who attacked them and a water monitor who administered a prolonged death grip to a block of wood. There was individual variation, so that one hedgehog ignored the objects and the other went wild for the blocks and tubing, chewing and toting them all over the place. Young animals displayed more curiosity than adults. In general, primates and predators showed the most curiosity.
Curious pigs
British scientists raised two groups of pigs in “modern intensive farming” conditions, with one difference. One group, the “substrate-impoverished” pigs, were kept on plain concrete floors. The “substrate-enriched” pigs had pens carpeted with straw and bark, each pen furnished with two tree branches.* The pigs were scored on their reactions to novel objects, which included a plastic toy tractor, a bicycle tire, a watering can, a bucket, a rubber boot, a three-legged stool, and a steering wheel. “These objects are of considerable interest to pigs,” the authors assure us.
The impoverished pigs were apt to fear the novel objects. When interest conquered fear, they just chewed on the object relentlessly. In comparison, the enriched pigs spent more time scampering about, rooting the object with their noses, and if they were in a test pen rather than their home pen, examining its panels, bars, drain, and flooring. In other words, the plain flooring provided to the impoverished pigs had helped create unimaginative pigs.
Curiosity can benefit even a captive pig. At a commercial pig farm, sows wore collars with transponders. When the pig walked into the sow-feeder, the transponder told the feeder whether that pig had been fed that day. If not, the feeder dispensed a meal. One sow found a collar that had fallen off another pig, and in the process of playing with it, discovered that if she carried it into the sow-feeder, she got fed again. Every day she’d use it as a meal ticket.
Curiosity carries risk. At a Kansas farm, 200 restless pigs lived in a field where nothing ever happened. They were thrilled one day when a teenager carrying an aluminum ladder entered their pen, and they were rapt at the spectacle of the teenager going to the concrete housing that held the irrigation pump, taking the heavy trapdoor off, lowering the ladder into the 20-foot-deep shaft, and descending into the shaft. The teenager was greasing the bearings of the pump when he was struck by a falling pig. Looking up with his lap full of pig, he beheld a ring of interested faces studying him. By the way the snouts jostled, he could tell that the pigs viewing him were being pushed by pigs behind them who also wanted a look, and that if he wanted to avoid being crushed by a pig avalanche, he needed to get out of the shaft. Clasping the pig in his arms, he slowly ascended the ladder, shouting to keep his fascinated porcine audience back.*
Memory
In 1964, the late psychologist Leslie Squier constructed a giant, rugged operant-conditioning test apparatus and tested some elephants at the zoo in Portland, Oregon, to see if their performance on such tests was like that of other animals. It was a simple enough task, and the elephants did well, pressing lit disks with their trunks, causing delightful sugar cubes to tumble into a steel hopper. The research was cut short after the elephants mastered the task. Eight years later, Squier and colleagues, wondering if it’s true that elephants never forget, located the equipment on a scrap heap, buffed it up, and set out to repeat the tests on three elephants that had been tested in the 1960s: Rosy, Belle, and Tuy Hoa
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Tuy Hoa, a 20-year-old elephant from Saigon, did so well that it was clear she remembered all about it. (Hey! Sugar cubes are back in style!) It took her only six minutes to rattle off 20 correct choices in a row and scarf up 20 sugar cubes. Rosy and Belle did so badly that it seemed they must have terrible memories, but then it was discovered that they had been quietly going blind in the intervening eight years and had a hard time seeing the disks light up. Veterinary help was called in.
Shorter-term memory is also valuable. Early in the morning, wild hamadryas baboons in Ethiopia were walking along a dry riverbed in Stink Wadi. The other baboons took their usual route under the railway bridge, but the elderly female Narba went directly up on to the bridge and drank water from a shallow dent in an iron plate. She seemed certain that the water was there, even though water evaporates within a few hours in the desert. Apparently she remembered that it had rained the night before in this area. Narba hadn’t been rained on, since it didn’t rain at the sleeping cliffs where she was at the time, but she would have been able to see that it was raining over by the wadi.
Becoming a Tiger: The Education of an Animal Child Page 39