The first such study was conducted in Germany by Nicholas Mulcahy and Josep Call, who let orangutans and bonobos select a tool that they couldn’t use right away even though the rewards were visible. The apes were moved away to a waiting room to see if they would hold on to their tool for later use even if the right occasion would arise only fourteen hours later. The apes did so, yet it could be (and has been) argued that they might have developed positive associations with certain tools, hence valued them regardless of what they knew about the future.14
This issue was addressed by a similar experiment in which apes selected tools, but this time the rewards were kept out of sight. The apes preferred a tool they could use in the future over a grape placed right next to it. They suppressed their desire for an immediate benefit to gamble on a future one. Once they had the right tool in hand, however, and got a second presentation of the same set of tools, they did pick the grape. Clearly, they didn’t value the tool over anything else, because if they did, their second choice should have replicated the first. The apes must have realized that once they had the right tool in hand, there was no point having a second one of the same kind, and that the grape was a better choice.15
These clever experiments were foreshadowed by Tulving’s proposal as well as by K?hler, who was the first to speculate about future planning in animals. There is now even a test in which, instead of presenting apes with actual tools, they are given an opportunity to fabricate them in advance. Apes learned to break a board of soft wood into smaller pieces to produce sticks with which they could reach grapes. Anticipating the need for sticks, they worked hard on having them ready in time.16 Their preparations resembled the behavior of wild apes, which travel long distances with raw materials that they turn on the spot into tools by modifying, sharpening, or fraying them. They sometimes bring more than one type of tool to a task in the forest. Chimps carry toolkits of up to five different sticks and twigs to hunt for underground ants or raid bee nests for honey. It is hard to imagine an ape searching for and traveling with multiple instruments without a plan. Just so, Lisala picked up a heavy rock that by itself was useless and that could serve its purpose only in combination with nuts that she had yet to collect as well as a hard surface located far away. Attempts to explain this kind of behavior without foresight invariably sound cumbersome and far-fetched.
The question now is whether similar evidence can be produced without reliance on tools such as spoons, umbrellas, or sticks. What if we consider a wider spectrum of behavior? How this might be done was again demonstrated by Clayton’s scrub jays. These birds routinely cache food, and although some scientists complain that this behavior offers a rather narrow window on cognition, it is a window nonetheless and one that differs radically from the one used for primates. It exploits an activity that corvids are particularly good at, just as tool studies exploit specialized primate skills. The outcome has been most remarkable.
Caroline Raby offered jays an opportunity to store food in two compartments of their cage that would be closed off during the night. The next morning they would get a chance to visit only one of the two compartments. One compartment had become associated with hunger, since the birds had spent mornings there without breakfast. The second compartment, on the other hand, was known as the “breakfast room” because it was stocked with food every morning. Given a chance in the evening to cache pine nuts, the birds put three times as many nuts in the first room as in the second, thus anticipating the hunger they might suffer there. In another experiment, the birds had learned to associate both compartments with different kinds of food. Once they knew what kind to expect, they tended to store a different food in each compartment in the evening. This guaranteed a more varied breakfast if they ended up in one of those compartments next morning. All in all, when scrub jays stash away food, they do not seem guided by their present needs and desires but rather by the ones they anticipate in the future.17
In thinking of primate examples without tools, the ones that come to mind are social situations in which it helps to be diplomatic. For example, chimpanzees sometimes arrange a secret rendezvous with the opposite sex. Bonobos don’t need to do so, since others rarely interrupt their sexual escapades, but chimpanzees are far less tolerant. High-ranking males don’t allow rivals near females with an attractive genital swelling. Nevertheless, the alpha male cannot always be awake and alert, hence occasions do arise for young males to invite a female to get away to a quiet spot. Typically, the young male spreads his legs to show his erection—a sexual invitation—making sure that his back is turned to the other males or that, with his underarm leaning on his knee, one of his hands loosely dangles right next to his penis so that only the wooed female can see it. After this display, the male nonchalantly wanders off in a given direction and sits down out of view of dominant males. Now it is up to the female, who may or may not follow. So as to give nothing away, she usually takes off in a different direction, only to arrive, via a detour, at the same spot as the young male. What a coincidence! The two of them then engage in a quick copulation, making sure to stay silent. It all gives the impression of a well-planned arrangement.
Even more striking are the tactics of adult males challenging each other for status. Given that confrontations are almost never decided between two rivals on their own but involve support for one or the other by third parties, it is to their advantage to influence public opinion beforehand. The males commonly groom high-ranking females or one of their male buddies before launching into a display, with all their hair on end, to provoke a rival. The grooming gives the impression of them currying favors in advance, knowing full well what the next step will be. In fact, there has been a systematic study on this issue. At Chester Zoo in the United Kingdom, Nicola Koyama recorded for over two thousand hours who groomed whom in a large chimpanzee colony. She also noted what kinds of conflicts arose among the males, and who allied with whom. When she compared records on both behaviors—grooming and alliances—from one day to the next, she discovered that males received more support from the individuals they had groomed the day before. This is the sort of tit-for-tat that we are used to in chimpanzees. But since this connection held only for the aggressors, and not for their victims, the explanation was not simply that grooming promotes support. Koyama viewed the connection as part of an active strategy. Males know beforehand which confrontations they are going to incite, and they pave the way for them by grooming their friends a day in advance. This way they make sure to have their backing.18 It reminds me of the politics at university departments, where colleagues come to my office in the days leading up to an important faculty meeting to influence my vote.
Observations are suggestive yet rarely conclusive. They do, however, give an idea under what circumstances future planning might be useful. If naturalistic observations and experiments point in the same direction, we must be on the right track. For example, a recent study suggested that wild orangutans communicate future travel routes. Orangutans are such loners that their encounters in the canopy have been described as ships passing in the night. They often travel on their own, accompanied only by their dependent offspring, and remain visually isolated for long stretches of time. Auditory information about one another’s whereabouts is often all they have.