In line with this misconception, the American philosopher Philip Kitcher labeled chimpanzees “wantons,” creatures vulnerable to whichever impulse hits them. The maliciousness and lasciviousness usually associated with this term was not part of his definition, which focused on a disregard of behavioral consequences. Kitcher went on to speculate that somewhere during our evolution we overcame this wantonness, which is what made us human. This process started with “awareness that certain forms of projected behavior might have troublesome results.”25 This awareness is key indeed but is obviously present in lots of animals, otherwise they’d run into all sorts of problems. Why do migrating wildebeest hesitate so long before jumping into the river they seek to cross? Why do juvenile monkeys wait until their playmate’s mother has moved out of sight before starting a fight? Why does your cat jump onto the kitchen counter only when you aren’t looking? Awareness of troublesome results is all around us.
Behavioral inhibitions have rich ramifications, which extend to the origins of human morality and free will. Without impulse control, what would be the point of distinguishing right from wrong? The philosopher Harry Frankfurt defines a “person” as someone who does not just follow his desires but is aware of them and capable of wishing them to be different. As soon as an individual considers the “desirability of his desires,” he becomes a person with freedom of will.26 But while Frankfurt believes that animals and young children don’t monitor or judge their own desires, science is increasingly testing out this very capacity. Experiments on delayed gratification present apes and children with a temptation that they need to actively resist for the sake of future gain. Emotional control and future orientation are key, with free will not far behind.
Most of us have seen the hilarious videos of children sitting alone behind a table desperately trying not to eat a marshmallow—secretly licking it, taking tiny bites from it, or looking the other way so as to avoid temptation. It is one of the most explicit tests of impulse control. The children have been promised a second marshmallow if they leave the first one alone while the experimenter is away. All they have to do is postpone gratification. But in order to do so, they have to go against the general rule that an immediate reward is more appealing than a delayed one. This is why we find it hard to save money for a rainy day, and why smokers find a cigarette more appealing than the prospect of lasting health. The marshmallow test measures how much weight children assign to the future. Children vary greatly on how well they do on the test, and their success predicts how they will fare later in life. Impulse control and future orientation are a major part of success in society.
Many animals have trouble with a similar task and don’t hesitate to eat food right away, probably because in their natural habitat they might otherwise lose it. For other species, delay of gratification is very modest, such as in a recent experiment with capuchin monkeys. The monkeys saw a large rotating plate, like a lazy Susan, featuring one piece of carrot and one piece of banana. Capuchins favor the second food. They first saw one and a little later the second item move by, while sitting behind a window through which they were allowed to reach only once. The majority of monkeys ignored the carrot, letting it pass right in front of them, to hold out for the better reward. Even though the delay between the two was a mere fifteen seconds, they showed enough restraint to consume considerably more banana than carrot.27 Some species, however, show dramatic control that is more in line with that of our own. For example, a chimpanzee patiently stares at a container into which falls a candy every thirty seconds. He knows he can disconnect the container at any moment to swallow its contents but also that this will stop the candy flow. The longer he waits, the more candies he will gather. Apes do about as well as children on this task, delaying gratification for up to eighteen minutes.28
Similar tests have been conducted with large-brained birds. We may not consider birds to need self-restraint, but think again. Many birds pick up food for their young that they could easily swallow themselves. In some species, males feed their mates during courtship while going hungry themselves. Birds that cache food inhibit immediate gratification for the sake of future need. There are many reasons to expect self-restraint in birds, therefore. The test results bear this out. Crows and ravens were given beans—a food they’d normally eat right away—after being taught that they could trade the beans later for a piece of sausage, which they liked better. The birds hung on to the beans for up to ten minutes.29 When Griffin, the African gray of Irene Pepperberg, was tested on a similar paradigm, he managed even longer waiting times. The parrot had the advantage that he understood the instruction “Wait!” So while Griffin was sitting on his perch, a cup with a less preferred food, such as cereal, was put in front of him, and he was asked to wait. Griffin knew that if he waited long enough, he might get cashew nuts or even candies. If the cereal was still in the cup after a random time interval—anywhere from ten seconds to fifteen minutes—Griffin would receive the better food. He was successful 90 percent of the time, including on the longest delays.30
Most fascinating are the many ways in which children and animals cope with temptation. They are not passively sitting and staring at the object of desire but try to occupy themselves by creating distractions. Children avoid looking at the marshmallow, sometimes covering their eyes with their hands or putting their head into their arms. They talk to themselves, they sing, they invent games using their hands and feet, and they even fall asleep so as not to have to endure the terribly long wait.31 The behavior of apes is not so different, and one study found that if given toys, apes are able to hold out longer. Toys help them take their attention off the candy machine. Or take Griffin, who about one-third through one of his longest waits threw the cup with cereal across the room. This way he didn’t have to look at it. On other occasions, he moved the cup just out of reach, talked to himself, preened himself, shook his feathers, yawned extensively, or fell asleep (or at least closed his eyes). He also sometimes licked the treat without eating it, or shouted “Wanna nut!”
Some of these behaviors don’t fit the situation at hand and fall under what ethologists call displacement activities, which occur when a drive is thwarted. This happens when two conflicting drives, such as fight and flight, arise at the same time. Since they cannot both be expressed, irrelevant behavior takes the pressure off. A fish spreading its fins to intimidate a rival may all of a sudden swim to the bottom to dig into the sand, or a rooster may interrupt a fight only to start pecking at some imaginary grains. In humans, a typical displacement activity is to scratch one’s head when asked a tough question. Scratching is also common in other primates during cognitive tests, especially challenging ones.32 Displacement activity occurs when motivational energy seeks an outlet and “sparks over” into extraneous behavior. The discoverer of this mechanism, the Dutch ethologist Adriaan Kortlandt, is still honored at the zoo in Amsterdam where he used to watch a colony of free-ranging cormorants. The wooden bench on which he spent hours following his birds is known as the “displacement bench.” I recently sat on it and obviously couldn’t resist yawning, fiddling, and scratching myself.