Some urban crows in Japan have learned how to crack nuts in a unique way. They drop the nut from a great height onto a busy road, let the passing cars crush it, and when the light turns green they swoop down onto the road and peck at the contents. The first crow that started this shtick probably did it by chance, and others followed and upgraded the technique. They did it by trial and error (sometimes ending in death for those who had not yet learned that you don’t cross on a red light), and with the encouragement of the positive reinforcement residing at the core of a nut.
Animals are constantly learning. A baby elephant learns how to use its trunk and the 40,000 muscles that activate it by practice methods that last for half a year; a chick learns how to find food by skittering after its mother and pecking where she digs; and a fledgling songbird learns how to trill its courting song by imitating its father. None of these animals received instruction; none of them had a teacher − a parent, another adult or a friend − who taught them what to do, and how. An animal can serve as a role model for those who observe it or if its presence draws attention to a learning opportunity, but it is not a teacher in the sense of actively teaching something. At least, that’s what we believed until recently.
One of those responsible for the change of thinking is Dr. Alex Thornton, from the University of Exeter, southwest England, who was in Israel to take part in a recent workshop about teaching. A few years ago, while researching in the Kalahari Desert, in South Africa, Thornton found what is considered one of the first manifestations of teaching in nature. His teachers and pupils are animals called meerkats.
What is a Brit – a redheaded Brit at that – doing in the Kalahari Desert with animals that seem to have stepped out of a cartoon?
“They really were the inspiration for a cartoon! Timon, one of the characters in ‘The Lion King,’ is a meerkat, and that always helps me explain to people what I am doing. The difference is that in the movie, Timon acts alone, but meerkats in nature are social animals that live in groups. As such, they learn a great deal from one another, so they are an ideal research platform for strategies of social learning. That is precisely where my interest lies: how the young in nature learn from the adults; how the information spreads within the group; and how social traditions are created. It can’t be helped that the natural environment of the meerkat is the Kalahari Desert, or that I study animals in their natural habitat and not in captivity. I live there for six to eight months a year, in heat that sometimes reaches 45 degrees [Celsius], but I am not forlorn. There is a research farm, which is run by Cambridge University, and we have running water, electricity and the Internet.
“The rewards are huge. Meerkats are very friendly animals and it is very convenient to study them. I can sit next to a meerkat just as I am sitting next to you now. With the aid of a brush and a little hair color, I can mark each of them, so I can differentiate among them and conduct observations and experiments.
And is this how you discovered that they have teachers and pupils?
“Yes. It was the second time teaching was discovered among animals, and so far only a few cases have been found.”
It’s quite surprising that there is hardly any teaching among animals, as intuition suggests otherwise. In David Attenborough’s nature films, for example, he describes vividly the devoted parents teaching their offspring how to fly or find food. Is it possible that our consciousness has been shaped by this kind of mistaken narration and by animated films in which the older lion explains the facts of life to his son in the authoritative voice of James Earl Jones?
“Nature films, and certainly animated films, tend to humanize animals for the benefit of the plot, and they do indeed shape our consciousness. But a close examination shows that parents do not teach their young how to build a burrow, and the members of the flock do not instruct their fellow birds about where to fly. Very often, the presence of parents or friends is essential − they serve as models or allow the others to learn more easily − but, generally speaking, there is no teaching.”
Yet in recent years, thanks to scientists like you, animals that make use of teaching have been found. How is it that this wasn’t discovered earlier?
“Until a few years ago, it was thought that teaching could not exist among animals, in principle. The reason was that the classic definition of ‘teaching’ was based on the teacher’s intention and on his awareness of knowledge gaps between him and the pupil: I know something you don’t know, hence I will teach you in order to narrow the gap between us. Because animals apparently lack what is known as ‘theory of mind’ − the ability to understand what is going on in another’s mind − it was inferred that teaching could not take place among them.”
And then the definition was modified?
“Yes, because it ignored the fact that evolution is smart enough to be able to bring about certain results in various mechanisms, including simple ones which do not necessitate theory of mind. The accepted definition of teaching among biologists today does not include the teacher’s consciousness, but several other traits. First, the individual who is considered the teacher is supposed to change his regular behavior in the presence of the pupil. That is, while teaching, the teacher does not do what he generally does, but acts in a distinctive way that is appropriate to the lesson. Second, the teacher invests in the pupil. It can be time or energy, but in any event he invests resources without obtaining a gain from it, or at least no immediate gain. And finally, it has to be shown that as a result of the teacher’s behavior, the pupil learned something he did not know before. Using these parameters, we can separate the teaching process from the other forms of learning in animals, and then it becomes possible to find teaching processes in nature.”
What do meerkats teach?
“They teach their pups to hunt. Meerkats are carnivores and have a wide range of food: snakes, lizards, small mammals, spiders and scorpions.”
“Fast, and therefore hard to get. And when it’s a scorpion, it’s also a dangerous food.”
How does the lesson proceed?
“Actually, it’s a series of lessons, which progress by degrees. For the first lesson about scorpions, the adult meerkat catches and kills a scorpion and brings the corpse to the young pup. The pup checks it out, fiddles with it and gets a sense of the prey. When the pup is a little older, the adult brings it a live scorpion after removing its stinger. The scorpion is still alive and puts up a fight, but it is not dangerous. When the pup has grown some more, the adult presents it with the whole living prey until, finally, the pup is ready to hunt on its own.”
“It is adapted to the pups’ developmental level − they are all the same age, because they were all born at the same time to the dominant female of the group − and it is also adapted to skill. During the whole time that the pup is trying to catch the scorpion, the teacher stands behind him and observes what he is doing. If, for example, the pup does not manage to catch the prey and the scorpion escapes, the adult brings it back to the pup and gives it another go. If the pup still has difficulty, the adult can bite the scorpion and weaken it, and thus facilitate things for the pup.”
How does the teacher know when it’s time to raise the bar?
“That is exactly what we asked, too: How does the adult know he must give the younger ones a dead scorpion; give the older ones a live scorpion without a stinger; and give the most highly developed ones a full-scale prey? Given, let us recall, that he has no theory of mind of the pups.
“To understand this, we recorded the calls the pups make when they ask for food, and which prompt the adults to bring them prey. We recorded the calls at different ages − the pups’ voices change with age, as with human children − and then played them back in the wrong context. For example, we played the recording of the calls made by older pups when younger pups were present, and that prompted the parents to bring the little ones live prey, which had not been tampered with. The inexperienced pups, unable to cope with the overly difficult lesson, just stood still and watched the prey escape. In contrast, when we played calls of young pups in the presence of older pups, the adults brought them a dead scorpion, even though at that age they were already capable of handling live prey. So the teaching mechanism is very simple − no more than stimulus and response − yet it achieves a complex result: teaching that is adapted to the learner’s needs.”
Are particular adults the teachers?
“Because this is a society in which all the adults look after all the pups, they are all teachers.”
Meerkats are mammals, meaning they have a relatively complex nervous system. Are there also simpler animals that engage in teaching?
“Yes. In fact, the first time teaching was discovered in animals, it was in ants. Scientists from Bristol made that discovery. In species of ants that live in large groups, a few individuals, the scouts, embark on a mission of looking for food or locating a site to build a new nest. After finding the site, they return to the existing nest and engage others to follow them. While on the road they secrete pheromones, which create an aromatic trail, and the other ants follow it. There is no need to teach the route. Those who follow the trail secrete their own pheromones, and thus the marked trail remains intact. But in ant species that live in small groups, there are not enough ants to preserve the trail before the aroma evaporates, and then the route needs to be memorized.
“This is where teaching comes in. Every scout ant that returns to the nest teams up with another ant, and a navigation lesson called ‘tandem running’ begins. The scout, now a teacher, runs first, followed by the pupil. During the run − to a new nest or a food source − the pupil uses its antenna to tap on the legs of the teacher ahead of it, thus signaling that it is still following. When the teacher speeds up, so does the pupil, and when the former moves more slowly, the latter also goes into lower gear. Occasionally the pupil stops, and then the teacher also comes to a halt and waits. The pupil embarks on a round of learning in the stoppage area, learning the local trail markers, and afterward returns to the patient teacher and the joint run continues.”
You’re describing a communications protocol. Why do you call this teaching?
“It is the teaching of knowledge, in which communication plays a major role. The tandem running is comparatively slow for the teacher, because it is delayed and does not progress directly to the food source. In fact, most of the time the teacher waits until the pupil completes its rounds. It could do the run alone four times as fast, meaning that time is invested in the pupil.
“One could say that the teacher modifies its regular behavior for the purpose of the lesson and adapts itself to the pupil. As I would do if I took you to a restaurant in an unfamiliar city, so that in the future you would know how to get there on your own. In that case, I will walk more slowly and stop along the way so that you can look around and memorize signposts that will help you navigate by yourself the next time.
“In the wake of the lesson, the pupil-ant learns the way far better than by doing it alone. Sometimes the pupil becomes a teacher afterward, and so the knowledge spreads in the colony.”
So it’s the pupil who sets the pace of the lesson?
“Precisely. The teacher supplies the knowledge, but the pupil determines the pace at which they will run and how many times they will stop. The communication enables feedback between teacher and pupil in both directions. There is a dialogue between them, not a monologue by the teacher.”
It’s almost a paean to teaching: private, experiential, adaptive and based on a system of feedback between teacher and pupil. Does the teacher behave differently with good and bad pupils?
“Yes, and this is perhaps less like what happens, or what ought to happen, among humans. You see it when the teacher waits for the pupil while the latter is making its learning patrol. If the wait becomes too long and the pupil does not return, the teacher gives up and leaves. So the question is, how long is the teacher willing to wait for the pupil? Researchers found that the better the pupils were − that is, the quicker they were − the more willing the teacher was to wait longer. If the pupils were poor, meaning very slow, the teacher did not waste time on them, and left. It was also found that the more value a lesson had − if the food source was richer, or the site of the new nest was better − the more the teacher was willing to wait. In other words, the teacher does an evaluation of the pupil and the lesson’s value, and behaves accordingly.”
As with the meerkats, the ants’ teaching mechanism is also very simple: a few rules of thumb and it works. If it’s all so good and simple, why isn’t it more widespread? Why did evolution not develop more animals that practice teaching?
“To begin with, I think there are far more teaching processes in nature than we think. This is a relatively new field. It was bogged down in human concepts of teaching, but I believe research will discover more and more examples. Besides that, in thinking about evolutionary processes we need to examine the conditions in which evolution will prefer learning by means of teaching over other learning mechanisms. Primates, for example − the various types of apes and monkeys − are very good at imitation, and they learn excellently by observing others and imitating them. In that situation, natural selection is unlikely to favor the evolution of teaching, and that is why you will never find teaching in monkeys.
“I can think of two conditions in which there is an advantage to teaching. First, when the individual needs to learn something that is critical for survival, but which is difficult to learn alone or is dangerous. Another condition involves learning motor behavior. You can’t learn how to play tennis by watching, it has to be an active experience – and if the teacher can enable that, it’s an advantage. These two conditions are met in the case of the meerkat pups.
“If we look at different species of felines as opposed to species of canines, we will find that teaching takes place with cats − house cats, cheetahs, caracals, etc. − whereas with dogs there is none. The reason is that dogs hunt in a pack, so as a pup you can acquire the experience you need simply by joining the pack. You observe and imitate the behaviors and the responses. Felines, in contrast, are solitary animals that do not live in a society (with the exception of lions, which do not teach), and therefore for them the task of hunting requires teaching. It’s known, for example, that house cats do something similar to what the meerkats do: the mother cat brings a live mouse and releases it next to its kittens, so they will chase and hunt it.”
Have your studies taught you anything about humans?
“As a species whose behavior is extremely complex, we of course need to learn thousands of things which are difficult or impossible to learn alone. So, the existence of human teaching is not surprising. We are a cooperative species, so that if I invest in teaching you something, I increase your fitness and thereby increase our advantage as a group − so I too gain.
“At the same time, I think we do not always acknowledge the fact that among humans the teaching and learning mechanisms are sometimes based on very simple forms of stimulus and response, just like among other animals. In other words, not only the complex content which the teacher or the parent transmits is learned, but also the small things he does without being aware of them.”
A natural skill
“Teaching is a natural cognitive ability,” says Prof. Sidney Strauss, formerly chief scientist at the Education Ministry and presently a lecturer and researcher at the College for Academic Studies, Or Yehuda. “In one form or another, teaching is found in all cultures and all societies − West and East, modern and ancient, among hunter-gatherers, farmers and in the industrial age,” he says. “In one of the oldest human texts – a Sumerian document dating from 4,000 years ago – students complain about their teacher and about the difficulty of his class. So, apparently complaints about teaching are also natural.
“The cognitive ability that makes teaching possible develops very early. By the age of 3, toddlers are able to teach their friends the rules of a simple game they have just learned. Even infants are equipped with a basic mechanism which is needed for teaching – for example, when they correct someone who did not insert a particular object into the right slot.
“That was why, when I met one of the world’s leading experts on the subject of learning in monkeys a few years ago, I was astonished to discover that among the chimpanzees − the closest species to us − teaching does not exist at all. Learning among them is based primarily on imitation. The big question, then, is how teaching, which is so crucial for humans, emerged. I am not talking about teaching in school, of course, but in life itself.
“For some years, I have been trying to promote research into teaching and extend it beyond the currently recognized discipline, which refers only to human beings and the modern period. I want to examine teaching also in cognitive, anthropological and biological terms, and to hold workshops with leading experts, like the one to which I invited Dr. Alex Thornton. I believe that a multidisciplinary discussion can help us formulate new and fruitful insights about the essence of teaching.”