The counterpunch came in 1953, when Daniel Lehrman, an American comparative psychologist, sharply attacked ethology.39 Lehrman objected to simplistic definitions of innate, saying that even species-typical behavior develops from a history of interaction with the environment. Since nothing is purely inborn, the term instinct is in fact misleading and should be avoided. Ethologists were stung and dismayed by his unexpected critique, but once they got over their “adrenaline attack” (Tinbergen’s words), they discovered that Lehrman hardly fit the behaviorist bogeyman stereotype. He was an enthusiastic bird-watcher, for example, who knew his animals. This impressed the ethologists, and Baerends recalled that while meeting the “enemy” in person, they managed to resolve most misunderstandings, found common ground, and became “very good friends.”40 Once Tinbergen became acquainted with Danny, as they now knew Lehrman, he went so far as to call him more of a zoologist than a psychologist, which the latter took as a compliment.41
Their bonding over birds went way beyond the way John F. Kennedy and Nikita Khrushchev bonded over Pushinka, a little dog that the Soviet leader sent to the White House. Despite this gesture, the Cold War continued unabated. In contrast, Lehrman’s harsh critique and the subsequent meeting of minds between comparative psychologists and ethologists set in motion a process of mutual respect and understanding. Tinbergen, in particular, acknowledged Lehrman’s influence on his later thinking. Apparently, they had needed a big spat to start a rapprochement, which was hastened by ongoing criticism within each camp of its own tenets. Within ethology, the younger generation grumbled about the rigid Lorenzian drive and instinct concepts, whereas comparative psychology had an even longer tradition of challenges to its own dominant paradigm.42 Cognitive approaches had been tried off and on, even as early as the 1930s.43 But ironically, the biggest blow to behaviorism came from within. It all started with a simple learning experiment conducted on rats.
Anyone who has tried to punish a dog or cat for problematic behavior knows that it is best to do so quickly, while the offense is still visible or at least fresh in the animal’s mind. If you wait too long, your pet doesn’t connect your scolding with the stolen meat or the droppings behind the couch. Since short intervals between behavior and consequence have always been regarded as essential, no one was prepared when, in 1955, the American psychologist John Garcia claimed he had found a case that broke all the rules: rats learn to refuse poisoned foods after just a single bad experience even if the resulting nausea takes hours to set in.44 Moreover, the negative outcome had to be nausea—electric shock didn’t have the same effect. Since toxic nutrition works slowly and makes you sick, none of this was particularly surprising from a biological standpoint. Avoiding bad food seems a highly adaptive mechanism. For standard learning theory, however, these findings came like a bolt out of the blue, due to the assumption that time intervals should be short while the kind of punishment is irrelevant. The findings were in fact devastating, and Garcia’s conclusions were so unwelcome that he had trouble getting them published. One imaginative reviewer contended that his data were less likely than finding bird shit in a cuckoo clock! The Garcia Effect is now well established, though. In our own lives, we remember food that has poisoned us so well that we gag at the mere thought of it or never set foot in a certain restaurant again.
American psychologist Frank Beach lamented the narrow focus of behavioral science on the albino rat. His incisive critique featured a cartoon in which a Pied Piper rat is followed by a happy mass of white-coated experimental psychologists. Carrying their favorite tools—mazes and Skinner boxes—they are being led into a deep river. After S. J. Tatz in Beach (1950).
For readers who wonder about the fierce resistance to Garcia’s discovery despite the fact that most of us have firsthand experience with the power of nausea, it is good to realize that human behavior was (and still is) often seen as the product of reflection, such as an analysis of cause and effect, whereas animal behavior was supposedly free of such processes. Scientists were not ready to equate the two. Human reflection is chronically overrated, though, and we now suspect that our own reaction to food poisoning is in fact similar to that of rats. Garcia’s findings forced comparative psychology to admit that evolution pushes cognition around, adapting it to the organism’s needs. This became known as biologically prepared learning: each organism is driven to learn those things it needs to know in order to survive. This realization obviously helped the rapprochement with ethology. Moreover, the geographic distance between both schools fell away. Once comparative psychology took hold in Europe—which is how I briefly ended up in a behaviorist lab—and ethology was being taught in North American zoology departments, students on both sides of the Atlantic could absorb the entire range of views and begin to integrate them. The synthesis between the two approaches did not take place just at international meetings or in the literature, therefore, but also in the classrooms.
We entered a period of crossover scholars, which I’ll illustrate with just two examples. The first is the American psychologist Sara Shettleworth, who for most of her career taught at the University of Toronto, and who has been influential through her textbooks on animal cognition. She started out in the behaviorist corner but ended up advocating a biological approach to cognition that is sensitive to the ecological needs of each species. She remains as cautious in her interpretations of cognition as one would expect from someone of her background, yet her work gained a clear ethological flavor, which she attributes to certain professors when she was a student as well as involvement with her husband’s fieldwork on sea turtles. In an interview about her career, Shettleworth explicitly mentions Garcia’s work as a turning point that opened the eyes of her field to the evolutionary forces shaping learning and cognition.45
At the other end of the scale is one of my heroes, Hans Kummer, a Swiss primatologist and ethologist. As a student, I avidly devoured every paper he wrote, mostly his field studies on hamadryas baboons in Ethiopia. Kummer did not just observe social behavior and relate it to ecology; he always puzzled about the cognition behind it and conducted field experiments on (temporarily) captured baboons. He later moved to captive work on long-tailed macaques at the University of Zürich. Kummer felt that the only way to test cognitive theories was by means of controlled experiments. Observation alone was not going to cut it, so primatologists should become more like comparative psychologists if they ever wished to unravel the puzzle of cognition.46
I went through a similar transition from observation to experimentation and was greatly inspired by Kummer’s macaque lab when I set up my own lab for capuchin monkeys. The trick is to house the animals socially, hence build large indoor and outdoor areas, where the monkeys can spend most of the day playing, grooming, fighting, catching insects, and so on. We trained them to enter a test chamber where they could work on a touchscreen or a social task before we’d return them to the group. This arrangement had two advantages over traditional labs, which keep monkeys, rather like Skinner’s pigeons, in single cages. First of all, there is the quality of life issue. It is my personal feeling that if we are going to keep highly social animals in captivity, the very least we can do for them is permit them a group life. This is the best and most ethical way to enrich their lives and make them thrive.