Dog Sense

by John Bradshaw

  Dogs do better in another aspect of “folk physics”: the ability to count. Because this ability is regarded as an indicator of intelligence, scientists have examined it in a wide variety of animals, including dogs. It’s clear that dogs can tell the difference between a half-full bowl of biscuits and one that’s a quarter full, but do they actually count the biscuits or just judge the size of the pile? Researchers have attempted to answer this question by using a technique first developed for the study of human infants.9 When babies as young as five months are shown one doll and then another, and then, after a brief gap, three dolls in the place where there logically ought to be two, they look at the three dolls for longer than expected—they seem surprised that the third doll has come from nowhere. Their reaction suggests that they had added together one doll plus one doll and were therefore expecting only two. It seems logical that dogs should also be able to do this: A mother dog who sees two of her puppies go momentarily out of sight should presumably be surprised (and get up to investigate) if, say, only one reappears.

  In the means-end test, dogs usually pull on the string that’s nearest to the food, not the one that’s actually connected to it.

  To test dogs’ ability to count, the researchers in this study used food treats rather than dolls. The dogs were shown first one treat being placed in front of them and then a second. Next, a screen was placed between them and the treats. When the screen was removed and either one treat or three were revealed, they stared at the treats for a long time, as if in disbelief. If there were two, as there should have been, they just glanced at them only briefly.

  Although rather few studies have been conducted on this topic, it seems that dogs have little intuitive grasp of how the world around them works. This was Thorndike’s conclusion from his puzzle-box experiments, and one that has been confirmed by all of his subsequent experiments. Of course, dogs can easily learn how to manipulate some specific aspect of their surroundings in order to get what they want—but they appear not to understand why the manipulation works, just that it does.

  Dogs, as the descendants of social animals, are likely to be much more attuned to one another than they are to the physics of their surroundings. Accumulated experience evidently plays a big part in enabling canids such as dogs to exploit their environment and find enough to eat; indeed, it would seem inefficient if each animal had to learn everything from scratch. Evolution should favor the transfer of skills from parent to offspring, and the longer the young are dependent on the parents, as in the canid “family pack,” the more frequent are the opportunities for this to occur. Thus there is good reason to conclude that dogs should have inherited some potential for learning from one another.

  This is not to say that one dog deliberately teaches another in the way that we teach our children. Biologists who study how one animal learns from another usually try to use simple explanations rather than those requiring the presence of complex mental processes. Start digging your garden, and your dog may try to “help” by digging alongside you. Is the dog really imitating what you’re doing? If so, why doesn’t she try to pick the spade up in her paws? More likely, your digging has simply drawn her attention to the soft earth—and, indeed, digging is a normal thing for a dog to do in soft earth. Biologists refer to this process as stimulus enhancement : It’s sensible for an animal to keep an eye on what other animals are up to, in case it sees something useful. But the observant animal’s subsequent behavior is more likely dictated by what it would normally do than by an urge to imitate the others’ actions precisely.

  Some studies have found no evidence for copying. Thorndike himself researched the question of whether his dogs could learn to escape from puzzle-boxes by watching other dogs that had already learned the trick, but he concluded that there was no evidence that they learned anything from observing the other dogs’ behavior. In another study,10 pet dogs watched through a Plexiglass gate as a trained German shepherd cross called Mora performed one of two tricks: lying down on her belly and lying down on one side, or “playing dead.” Both are tricks that many dogs can do and, indeed, might have been trained to do. The twist was that the trainers issuing the commands to Mora used arbitrary words as the cues (their own first names), which the observer dogs had presumably never heard before—“tennie” for lying on the belly and “josep” for playing dead. Each observer dog was allowed to watch (and hear) the demonstration five times. The researchers then tested to see if the observer dogs had learned the commands from watching Mora. Apparently not: When tested with the commands, none of them seemed to know what to do. A few lay down on their bellies, but not in response to “tennie” (perhaps they were merely tired), and none “played dead,” with or without the “josep” command. Children gain the ability to learn through imitation at about eighteen months of age, so the dogs did not do very well at this task, if judged by human standards.

  However, other research11 has shown not only that dogs can copy other dogs but also that they are selective and logical about what they copy. In one study, dogs between twelve months and twelve years old were trained to obtain food from a box that opened when a wooden handle was pulled down. Most dogs would naturally do this by grabbing the handle in their teeth and pulling it, but these particular dogs were trained to pull it down with their paws. Next, other dogs were allowed to watch the dogs performing their new trick. If all the trick did was draw attention to the handle and the food, then most of the dogs should simply have pulled the handle using their mouths. But some of the dogs started using their paws, as the demonstrator dogs had done, suggesting that they were copying the action itself.

  A dog demonstrating pulling a handle with its paw while holding a ball in its mouth

  The experimenters added a twist to this test that seems to show why the dogs sometimes copied the action of the demonstrator. Each of the dogs who were demonstrating the handle-pawing action had been trained to hold a ball in their mouth while doing so (as shown in the illustration). When actually demonstrating, they were sometimes given the ball to hold while at other times they weren’t. When the demonstrator was holding a ball, the other dogs often used their mouths; it was as though they were thinking “That dog is using its paw only because its mouth is full—I’ll use my mouth, it’s easier.” In contrast, when the demonstrator wasn’t holding a ball in its mouth, most of the observers used their paws, as if thinking “That dog is using its paw, not its mouth, so that must be the only way to get the food.” This experiment, if understood correctly, suggests that dogs are capable of quite sophisticated reasoning. (Human children can make deductions of this type when they’re as young as fourteen months.)12 Additional experiments like this one may lead to more insight into what dogs are capable of thinking. Perhaps we’ll find out that dogs are better at imitating when they’re trying to get hold of something they can see than when doing something simply to please their owners, such as lying on their bellies or playing dead.

  In any case, dogs’ abilities to solve problems and to learn from observing other dogs should not be explained glibly in terms of the emergence of similar abilities during the development of human infants. Dogs develop skills and insights that are appropriate for their own species; we do likewise. For example, human infants begin to acquire language skills at an early age (something dogs never achieve) but are older than dogs when they acquire the ability to imitate selectively. Dogs, in turn, have inherited a set of learning skills from their canid ancestors that evolved over millions of years to allow cooperative hunting and rearing of young. Hunting as a pack can be only as efficient as the least experienced member of the pack, since it will be the weakest link that allows the prey to escape. Young canids must therefore pick up skills from their parents as quickly as possible if they are not to jeopardize the hunting success of the pack. Biologists are only just beginning to understand dogs’ ability to learn from each other: The necessary experiments are difficult to design and the results are often open to more than one interpretation.

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p; Unlike the other canids, domestic dogs have the opportunity to also learn from people. Indeed, the close cooperation that can occur between man and dog suggests that domestication is likely to have enhanced this aspect of dogs’ intelligence. Most of the abilities I’ve discussed so far in this chapter are probably held in common with wolves and other canids—it’s just that we know more about domestic dogs because they’re easier to study. Yet the fact remains that dogs are domesticated and other canids aren’t, so the question arises: Is there anything about the dog’s intelligence that is a unique product of the domestication process, one that has enabled dogs to interact with us at a level of sophistication no other animal can match? In proportion to body size, the dog’s brain is somewhat smaller than that of its ancestor, the wolf, so it’s unlikely that dogs are simply smarter than wolves. Nevertheless, dogs can outperform even chimpanzees, probably the most intelligent mammals apart from man, in certain selected tasks. Nowadays biologists tend to think of animals not in terms of whether they’re more or less intelligent than one another but, rather, in terms of how their mental processes match the demands of their lifestyles. The lifestyle of dogs is so intimately connected with our own that it’s reasonable to look for special intellectual capacities that they may have gained during the long process of their domestication.

  One area in which dogs especially outdo chimpanzees is in their ability to extract information from what humans are doing—in particular, their ability to read human faces and gestures. Even hand-reared chimpanzees take a long time to learn this. And they can become confused when, for example, the person who first trained them is replaced, even if that person does his or her best to behave in exactly the same way as the original person. In contrast, dogs trained by one person can quickly learn another person’s version of the same commands. Dogs are particularly good at following pointing gestures, outperforming even chimpanzees. There is currently some argument among scientists about whether or not this ability is a unique product of domestication, but what seems most likely is that it was present to begin with, pre-domestication, and has been refined and developed since (though what its function might have been for wild wolves is unclear).

  Dogs’ ability to follow pointing gestures (and, by inference, other human gestures as well) is not quite what we would expect intuitively. Like humans, dogs can follow not only pointing with the arm that’s nearest to the target (in the tests, usually a pot covering a food treat) but also cross-pointing, with the opposite arm. They prefer to follow a pointing arm even when the person pointing is nearer to, or moving toward, the “wrong” target. However, dogs do have their limitations. They take much less notice of a pointing finger than a pointing arm (children are happy with either)—but they do follow a pointing leg! The rule seems to be “Take the direction indicated by whatever whole limb is obviously pointing somewhere.”

  There is also some argument about whether dogs are born with the ability to follow pointing gestures or, conversely, have to learn it. Sixweek-old puppies seem to know what pointing means but are less good at following it than adult dogs are—the puppies may just be too easily distracted. There’s little doubt that this ability can be refined by training; for example, gundogs that are highly attentive to their handlers test better than other types of dog. It’s also possible that domestication has prepared dogs to learn the significance of pointing very quickly, without giving them an instinctive ability that they can use the very first time they need it. But the response to pointing is clearly not universal: In some studies of pet dogs, over half did not respond spontaneously to pointing. Clearly, a strong learning component is involved. Some dogs seem to find it difficult to learn to follow pointing even when rewarded for doing so, but many of these are dogs from shelters who may have become fearful of outstretched hands due to physical punishment that they received in the past. The unanswered question is (a) whether the underlying ability is universal but some dogs learn not to respond to hands because they deliver punishment or (b) whether all dogs have to learn the significance of pointing and some simply find the task easier than others.

  Following a cross-point

  Although pointing has become the scientists’ favorite experimental tool, it is by no means the only activity to which dogs are particularly attentive. They also follow gestures such as nodding and hand movements much more attentively than most other animals do. In addition, dogs seem fascinated by people’s eyes and faces: They will follow the direction of their owner’s gaze almost as reliably as they will follow pointing.

  Domestication’s main effect on dogs seems to be that it has rendered humans their most relevant source of information. For example, most dogs faced with the impossible problem of getting a tasty food treat out of a locked box turn to the nearest person for help within a few seconds, whereas even hand-raised wolves just keep scrabbling at the box. However, wolves outscore dogs when quick decisions have to be made, whereas dogs will tend to repeat what they’ve learned from people, even when it’s obviously the wrong thing to do.

  In one experiment that supports the idea that dogs are hyperdependent on people,13 a comparison was made between dogs, ten-month-old human infants, and wolves in terms of their ability to follow the progress of a ball between two screens. The experimenter first hid the ball behind one of the screens four times, each time talking to and maintaining eye contact with the dogs. Each time, the dogs were then allowed to retrieve the ball from behind the screen and play with it. Next, the experimenter walked behind the first screen but quite obviously left the ball behind the other screen, finally showing the dogs her empty hands. The dogs nonetheless continued to look for the ball behind the first screen, even though they had seen it disappear behind the second one. Clearly, the attention they had received from the experimenter on the first four occasions had marked the first screen as the best place to try first. The ten-month-old infants made exactly the same mistake, again apparently prioritizing social cues. The wolves, however, believed their eyes and went straight to the second screen. Giving a low priority to cues given by humans, they instead relied on their interpretation of the physical world—in this case, presumably a skill that would enable them to guess where a prey animal was most likely to be hiding.

  Interestingly, however, the dogs weren’t incapable of understanding where the ball had gone. They did get the right answer when the ball was moved from one screen to another by an invisible string rather than by a person. Evidently, their first priority was always to do what a human had encouraged them to do in the past. Even hand-raised wolves maintain a sufficient degree of independence from people to keep their minds on the problem as presented to them; dogs are just too easily distracted, too eager to please a human.

  Just because they can follow a human’s gaze or hand gesture doesn’t necessarily mean that dogs understand what that person is thinking. They might simply be using the person’s eyes as a convenient but otherwise arbitrary pointer as to what they should attend to next. Two remarkable studies done in France14 have exposed some of the dog’s limitations. Detailed comparisons were made between guide dogs, owned by blind people for several years, and ordinary pet dogs living with sighted owners. First, the researcher studied how the dogs tried to get food from their owners. They all used the standard doggie routine of looking forlornly at their owner, then at their bowl, and then back again: The guide dogs gave no indication that they knew their owners were blind. The only difference was that the guide dogs made louder slurping noises, which their blind owners could and did attend to. This tactic can be accounted for by simple associative learning—the dogs had learned that food followed when they made the noises—and doesn’t prove that the dogs understood anything about blindness. Next, the study examined how dogs draw the attention of their owners when they are trying to get at a toy made inaccessible behind a heavy wooden box. Here, too, the pantomime of looking back and forth between the owner and the toy went on, irrespective of whether the owner could see it or not. Other scenarios produced simil
ar results, such as the owner offering the dog a different toy instead of the one it wanted: Again, no difference. There was no indication that the guide dogs knew that their owners were blind and that they thus had to rely on other cues, such as sounds, to tell them which way to point their heads.