In a second experiment, we tested peripheral males, outsiders shifting between groups. Of 26 outsider males who were shown food, not one called out. They beelined to the food and either consumed it on the spot or gobbled a few pieces and then moved to a new location with a stash. Even if other monkeys discovered them with the food, the outsiders were never attacked. Thus, it seemed that members of an established rhesus community abide by a rule that says: Attack members that find food and don’t share it. And the corollary seems to be: Why bother risking harm by assaulting onetime transgressors?
Thus research indicates that animals can inhibit their impulses and punish those who violate community rules. But what about empathy? What about Binti? Unless we can establish that animals understand the thoughts and feelings of others, we cannot assume that their behavior is moral as humans understand the word. Codes of moral behavior are founded on beliefs of right and wrong. How we form those beliefs is based on an idea of justice, a consideration of how particular actions affect others. And to understand how our behavior affects others requires empathy.
Ethologist Frans de Waal has offered several observations of apparent empathy among nonhuman primates in his 1996 book Good Natured: The Origins of Right and Wrong in Humans and Other Animals, but richer insights come from a series of studies published about 40 years ago, when standards for animal welfare were minimal. Today the experiments would be deemed unethical, but they do provide a window on animal emotion that has yet to be opened by more recent observations.
The experiments were designed by psychologist Robert Miller and his colleagues to see if a monkey could interpret another monkey’s facial expression, a presumed indicator of emotion. First, a researcher trained rhesus monkeys to pull a lever to avoid electroshock after hearing a specific sound. Then one of the monkeys, the actor, was put in a room with a lever and a live television image of a second animal, the receiver, which was out of sight and earshot. The receiver was exposed to the sound that indicated a shock was coming but lacked a lever to avoid it.
The assumption underlying this experiment was that the receiver would hear the sound, anticipate the shock, and show fear on its face. If the actor understood the receiver’s facial expressions, then he would use this information to pull his lever. If the actor failed, both animals received a shock. Because shock trials were presented randomly, and neither animal could hear the other, there was no way to predict the timing of a response except by using the receiver’s image in the monitor. As it turned out, the actor pulled the lever significantly more when the receiver heard the sound. Miller concluded that the actor was able to read the receiver’s facial expressions. Moreover, he and his colleagues suggested that the animals behaved cooperatively: to avoid the shock, the receiver gave a signal and the actor read the receiver’s signal.
Did the receiver intend to provide information to the actor? Was this a cooperative effort? The receiver, to be sure, must have felt helpless and afraid. But to establish that he was signaling the actor, one would have to demonstrate that he knew about the actor’s presence. And, given the experimental design, he certainly did not. Rather, the receiver’s response was elicited by the sound, perhaps as reflexively as we kick out our foot in response to the doctor’s tiny mallet. It seems likely that the actor picked up on a change in the receiver’s activity, one that was consistent enough to predict the shock. Using an expression to predict a response is not the same as seeing the expression as an indication of another’s emotions.
This experiment leaves many loose ends. Although it is clear that rhesus monkeys can learn to avoid shock by attending to a facial expression, we don’t know if this response is motivated by empathy, and empathy is necessary for altruism. One has to feel what it would be like to be someone else, to feel fear, pain, or joy. We don’t know whether the actor was even aware of the receiver’s feeling. There is no reason for the actor to care. From the actor’s perspective, all that matters is that the image displayed on the video monitor functions as a reliable predictor of shock. A better experiment would allow the actor to see what was happening to the receiver but would restrict the shock to the receiver.
In a 1964 study, Jules Masserman and his colleagues ran a different experiment, again with rhesus monkeys. An actor was trained to pull one of two chains to receive its food in response to a brief flash of blue or red light. Next, a receiver was put into cage nearby, where the first could see it. The experimenter then changed the consequences of responding to the color of the flash. Pulling in response to one delivered food; pulling in response to the other delivered both food to the actor and a severe shock to the receiver. Most actors tested pulled the chain delivering the shock far less often than the chain delivering food. Two of the 15 actors even stopped pulling both chains for between 5 to 12 days; interestingly, these two had both experienced being shocked. When the actors were paired with new receivers, most continued to refrain from pulling the chain that delivered the shock. There was a tendency for pairs that knew each other well to show more altruistic behavior than pairs that were unfamiliar.
What is most remarkable about this last experiment is the possibility that some monkeys refrained from eating to avoid injuring another. Perhaps the actors empathized, feeling what it would be like to receive the shock. Alternatively, perhaps seeing another monkey grimace in pain is unpleasant or threatening, and rhesus monkeys will do whatever they can to avoid unpleasant conditions. Or perhaps the actor worried that one day it might be the recipient of a shock. Although refraining from eating appears to be a response of empathy or sympathy, it may actually be a selfish response.
As the experiments show, animals are by no means robots driven solely by instinctual responses. They are sensitive to their social and ecological environments, and under certain conditions they can inhibit one response and favor another. Moreover, they can punish others and sometimes alleviate another’s pain. But no experiment to date has provided evidence that animals are aware of others’ beliefs or intentions. And without such awareness, there can be no ethical judgment.
Asking what it means to be moral challenges us to think about how our own capacity for moral agency came about. Monkeys demonstrate rulelike strategies for promoting the welfare of a group, including maintaining peace, observing boundaries, and sharing food. And they can abide by these rules without necessarily understanding them. Humans are a different kind of animal: We can consciously evaluate whether behavior is right or wrong, but we tend to do so depending on the conventions of our society. In that regard, the roots of our moral intuition are entwined with the self-interest shown by other animals. What we don’t know is exactly when the uniquely human capacity for empathy and justice emerged in our ancestors and how cultures build on a universal moral sense. What is certain is that our moral potential is still far from fully realized. As Agesilaus, a Spartan king, said, “If all men were just, there would be no need of valor.”