There are other indicators of a lack of empathy in monkeys, such as the “exasperating” stories of baboon watchers in the Okavango Delta of Botswana about adults ignoring the fear of youngsters facing a water crossing. Standing panicky at the water’s edge, young baboons risk getting killed by predators, yet their mothers rarely return to retrieve them. They just keep traveling. It’s not that a baboon mother is entirely indifferent:
She appears genuinely concerned by its agitated screams. But she seems to fail to understand the cause of this agitation. She behaves as if she assumes that if she can make the water crossing, everyone can make the water crossing. Other perspectives cannot be entertained.
Another Dickensian observation was made during an exceptional flood, which forced the baboons to swim from island to island. One day the adults crossed to another island, leaving almost all of the young stranded behind. The latter were highly stressed, tightly bunched together in a tree, emitting agitated barks. Fieldworkers following the adult baboons could hear the contact calls of the young in the distance, and the adults themselves occasionally oriented toward them but gave no answering barks. The juveniles later managed to swim across and reunite with the troop.
All of this suggests intact emotional contagion but an inability to adopt another’s point of view. This is a familiar deficit in many animals as well as young children. Sometimes it takes amusing forms. At home, we have a black-and-white tomcat, Loeke, who is scared to death of strange people, especially men with big shoes. He must have suffered trauma before we adopted him. As soon as visitors enter our house, he races upstairs in total panic and wriggles his way under our bedcovers. He can stay there for many hours at a time, but remains of course extremely visible. We see a bed with a conspicuous bulge and know exactly where Loeke is, but I bet he thinks that since he can’t see anybody, nobody can see him. The bulge even purrs if we whisper to it. As soon as we close the front door behind the departing visitors, we look at our watch to see how long it takes Loeke to return to the living. It rarely takes him more than twenty seconds.
But lack of perspective-taking can also take heartbreaking forms, as in the baboons above. I remember visiting a Japanese monkey park where the ranger told me how they needed to keep first-time mothers from entering the hot water springs, since they are likely to drown their babies. Young mothers apparently don’t pay sufficient attention to the situation of a baby clinging to their bellies, perhaps thinking that if their own heads are above the surface no one can possibly be in trouble. I have also seen captive monkeys performing dangerous acrobatics in a large spinning wheel in which infants had been playing, forcing the latter to cling to its frame for dear life. An injured young female macaque followed her mother around with a broken, lifelessly dangling arm, without the mother ever adjusting even a tiny bit to her daughter’s handicap.
How different from a chimpanzee mother I knew, who accommodated every wish of her juvenile son who had a broken wrist, even to the point of letting him nurse, though he had been weaned years earlier. Until his arm had healed, she put him ahead of his younger sibling. Sensitivity to another’s injuries, other than obvious open wounds, requires appreciating how someone’s locomotion is hampered. Apes definitely notice this, as do dolphins and elephants. Examples of elephants helping humans are hard to come by, but Joyce Poole offers the account of a matriarch who had attacked a camel herder, breaking the man’s leg. The same elephant returned later, and with her trunk and front legs moved him to a shady spot under a tree, where she stood protectively over him. She occasionally touched him with her trunk and chased off a herd of buffaloes. She watched over him an entire day and night, and when a search party showed up the next day she was resistant to let them retrieve their colleague.
Monkeys, in contrast, ignore handicaps and seem to have little clue about grief or loss. A typical study is one by Anne Engh, who measured stress levels of baboons who had witnessed a family member being dragged away by a leopard, lion, or hyena. Predation accounts for a high percentage of deaths, and so Engh had many cases to study. Sometimes her baboons literally heard the fearsome predators crunch the bones of their kin. As one might expect, the ones left behind had an elevated stress level, which Engh measured by extracting corticosterone (a stress hormone) from droppings. She also found that bereaved baboons groomed others more, probably as a way to reduce stress and build new relationships to replace lost ones. About one female, she notes: “So great was her need for social bonding that Sylvia began grooming with a female of a much lower status, behavior that would otherwise be beneath her.”
Engh concludes that, like humans, baboons rely on friendly relationships to help them cope with stress. The similarities are indeed obvious, but isn’t there also a glaring contrast? Other baboons never changed their behavior toward those who had just lost friends and family, which is a fundamental difference with our own species. We are plenty aware of another’s loss, keeping it in mind for years. Chimpanzees too seem sensitive, as when the adolescent daughter of one of our females had been sent off to another facility. We were struck by the enormous amount of grooming others directed at the mother in the ensuing weeks. Chimpanzees offer true solace in a way that we humans understand, whereas bereaved baboons are left to regulate their own internal state. They do seem to have the same needs, but can’t expect much consideration from others. No wonder a pioneering baboon watcher characterized this monkey’s life as “one continual nightmare of anxiety.”
The limited sensitivity of monkeys to others seems due more to cognitive than emotional factors. Monkeys do feel the distress of others but have no good grasp of what’s going on with them. They can’t step back from the situation to figure out the other’s needs. Every monkey lives in its own little bubble.
Yellow Snow
Progress in science has often come from attention to exceptions. The co-emergence hypothesis, too, must have a few.
Monkeys do sometimes show glimpses of the understanding that led to the advanced empathy typical of our own branch of the family tree. These incidents are rare, which is why they are exceptions, but show borderline understanding. The owner of a tame capuchin monkey, for example, told me how his pet once bit a visitor when the latter was trying to hand-feed it grapes. The monkey had given only a tiny nip—no blood was visible—but the woman looked hurt and dropped the grapes. The monkey promptly and gently hugged her with both arms around her neck. It reacted to the woman’s distress while ignoring the grapes, which had fallen to the floor. To all present, it looked exactly like human solace. In our own capuchin colony, we have also seen such incidents, but we use such strict criteria to determine if primates have consolation that our capuchins have never satisfied them.
Further incidents in our capuchins concerned females so heavily pregnant that they refused to descend to the ground. Capuchins feel safer higher up. Trays with fruits and vegetables for the colony are put on the floor every evening, however. We have seen close friends and family grab mouth- and handfuls of food (sometimes wrapping food into their tails) and climb up to the gravid female’s platform, where they spread it all out in front of them, after which they happily eat together.
Another example has stuck in my mind for decades, ever since I saw a photograph by Hans Kummer, a much-admired Swiss expert of hamadryas baboons. The photo shows a juvenile monkey using an adult’s back to climb down from some rocks, accompanied by the following caption by Kummer: “After vainly trying to descend over a difficult passage, a one-year-old has started to scream. His mother finally returns and offers him her back as an additional step.” My question here is if such assistance wouldn’t have required the mother to appreciate the juvenile’s need.
Monkeys occasionally assist one another’s climbing efforts, as a baboon mother does here with her infant.
Anindya Sinha, an Indian primatologist, witnessed similar incidents in wild bonnet monkeys. On three separate occasions, a juvenile tried to climb or jump up a parapet but was unsuccessful. After repeated attem
pts, an adult male who had been watching reached down, grasped the arm of the juvenile, and pulled him up. Only in one case was the male’s attention drawn by the juvenile’s calls—in the other two cases, the males were unmoved. The helpers were always alpha males of their troop, but a different individual in every observed instance.
Barbara Smuts relates how adult male baboons sometimes reassure distressed infants by softly grunting at them. By itself, this is already interesting, as it suggests vocal consolation. But Smuts also saw a male do so while, like the monkeys above, he seemed to identify with an infant’s intentions. Enjoying the grooming attention of her mother, the male, Achilles, watched the antics of a female infant who tried to climb a sandy mound. When she almost reached the top, she slipped and slid to the bottom. As soon as this happened, Achilles directed some reassurance grunts at her.
Baboons may even express vocal relief when an awkward situation comes to an end, indicating appreciation of the situation others find themselves in. In his usual entertaining style, Robert Sapolsky tells the story of an infant born to a particularly maladroit mother, whose offspring was often forced to cling to her tail:
One day, as she leapt from one branch to another in a tree with the kid in that precarious position, he lost his grip and dropped ten feet to the ground. We various primates observing proved our close kinship, proved how we probably utilized the exact same number of synapses in our brains in watching and responding to this event, by doing exactly the same thing in unison. Five female baboons in the tree and this one human all gasped as one. And then fell silent, eyes trained on the kid. A moment passed, he righted himself, looked up in the tree at his mother, and then scampered off after some nearby friends. And as a chorus, we all started clucking to each other in relief.
Such observations suggest that baboons do not just react to external signs of distress, such as calls or facial expressions, but that it matters to them that a fallen infant gets up again or that a mother and infant are reunited.
Then there’s the curious case of Ahla, a baboon employed by a goat farmer. Ahla knew every mother-lamb relationship in the herd. When mothers and kids were kept in separate barns, she’d come into action as soon as a kid started bleating. She’d go pick it up and carry it under her arm to the other barn. There she would shove the kid underneath the right female for nursing, never making a mistake. This obviously required knowledge of relationships, but perhaps more. I doubt very much that one could train an animal to perform such a task if it lacked any understanding of why baby goats bleat, and indeed Ahla was said not only to be eager but a “maniac” at putting mothers and offspring together.
We should be careful not to overinterpret, of course, but in all of these cases monkeys give indications of perspective-taking. The fact that they do not do so consistently, and perhaps only in relation to a narrow set of circumstances, may explain why systematic studies of targeted helping or consolation in monkeys typically come up empty-handed. These primates just act like this too sporadically.
The only natural situation that may be common enough for a serious study is so-called bridging behavior. Some South American primates have prehensile tails and create live bridges between trees for their older offspring (younger offspring simply cling to their mother during travel). When moving through the canopy, the mother holds on with her tail to one tree while grasping a branch of another with her hands, hanging suspended like this until her offspring has crossed over. Short of moving over the forest floor, which is too dangerous, the young would be unable to travel without these maternal bridges. It is an intriguing everyday helping act that begs careful observation since it may reveal the degree to which monkeys take another’s abilities into account. When I followed capuchins in the forest, I didn’t see any of it, but this is because these monkeys are such great jumpers. The larger and heavier primates, such as howler and spider monkeys, do produce bridges, sometimes even for unrelated juveniles. Females are said to adjust their behavior to new situations, such as an offspring with a broken arm or a forest with unusually wide gaps between its trees.
Juveniles sometimes cry to solicit their mother’s help, but more often than not she bridges spontaneously. She decides which distances her offspring can or cannot handle, and that obviously changes with age. What a wonderful setup to test perspective-taking, especially since the monkeys’ behavior can be directly compared with that of apes, such as orangutans, who do the same (without tail) by swinging small trees until they can pull them together for their young to cross over. Do orangs do so with greater insight into their offspring’s needs than South American monkeys have? I’d expect so, but someone will need to make sure.
For the moment, the proposed empathy differences between monkeys and apes remain intact, although they seem less absolute than suggested. So, what about the other part of the co-emergence equation: mirror responses? Here we do seem to have a radical difference. Despite many, many attempts to test monkeys with mirrors under all sort of circumstances, they just don’t pass the rouge test. Positive results have been claimed, but none have stood up to scrutiny. It’s widely accepted, therefore, that monkeys don’t pass. This doesn’t mean that they find mirrors totally baffling or that they lack any sense of self. They must have some self-awareness, because no animal can do without it. Every animal needs to set its body apart from the surrounding environment and have a sense of agency. You wouldn’t want to be a monkey up in a tree without awareness of how your own body will impact a lower branch on which you intend to land. Or if you’re engaged in rough-and-tumble fun with another, what would be the point of gnawing on your own foot? Monkeys never make this mistake, happily gnawing on their partner’s foot instead. The self is part of every action an animal—any animal—undertakes.
In a study with the intriguing subtitle “Tales of Displaced Yellow Snow,” Marc Bekoff investigated the reactions of his dog, Jethro, to patches of discolored snow outside Boulder, Colorado. With gloved hands, Bekoff would pick up a patch of urine-soaked snow freshly marked by another dog, out of view of Jethro, and bring it to a place next to a bicycle lane, where Jethro would discover it. Bekoff undertook this experiment—which must have looked positively weird to onlookers—to see if Jethro could tell his own markings from those of other dogs. Of course, he could. He was far less inclined to mark over his own urine than that of other dogs. Self-recognition takes many forms.
When it comes to mirrors, too, things are less clear-cut than they seem. Monkeys, for example, are able to use a mirror to locate food. If you hide food that can be found only by using a mirror to look around a corner, a monkey will have no trouble reaching for it. Many a dog can do the same: Holding up a biscuit behind them while they watch you in a mirror makes them promptly turn around. But even though dogs understand mirror basics, try to mark them surreptitiously, or try to do so with a monkey, and all of a sudden they are at a loss. It is specifically the relation with their own body, their own self, that they fail to grasp.
On the other hand, the standard claim that monkeys see a stranger in the mirror is questionable. To test it, we conducted a simple experiment that, surprisingly, no one had ever tried before. We compared how monkeys react to their mirror image with how they react to strangers, testing capuchins in front of a Plexiglas panel behind which they faced either a familiar monkey, a stranger of their own species, or a mirror. Could they tell the difference?
They treated their mirror image quite differently from real monkeys, and did so within seconds. They didn’t need any time to notice the difference. Apparently, there are many levels of mirror understanding, and our monkeys never confused their reflection with another monkey’s. For example, they reacted to strangers by turning their backs, barely glancing at them, whereas with their own reflections they made prolonged eye contact as if they were thrilled to see themselves. Some of the tested monkeys had young offspring, and since we never separate mothers and infants, the little ones were present during tests. For me, the most telling finding of the whole s
tudy was that when there was a stranger on the other side, mothers held their infants tight, not letting them wander around. During mirror tests, on the other hand, they let their kids roam freely. Given how conservative mother monkeys are when it comes to danger, this convinced me more than anything that their reflection was no stranger to them.
Both with regard to empathy and self-recognition the lines separating species remain intact, yet they are perhaps a bit vaguer than at first appears. It’s always the same story: We start out postulating sharp boundaries, such as between humans and apes, or between apes and monkeys, but are in fact dealing with sand castles that lose much of their structure when the sea of knowledge washes over them. They turn into hills, leveled ever more, until we are back to where evolutionary theory always leads us: a gently sloping beach. I do believe that the co-emergence hypothesis offers useful clues about the steepness of the beach’s slope, but wouldn’t be surprised if this turns out to be a temporary obsession. We’re already facing an avalanche of new studies, not only on monkeys, but also large-brained birds and canids, that address perspective-taking, consolation, and mirror self-recognition. The leveling waves are in full swing.
The Age of Empathy Page 16