Some animals, such as chimpanzees and bumblebees, are capable of acquiring new skills that they cannot learn by doing research on their own. They do this by copying the modus operandi of members of their social group who do master the skill. Two European studies published this Wednesday in journals from the Nature group have described, for the first time, this phenomenon in species other than humans.
Cultural accumulation—the name given to this capacity for learning that is impossible from individuality—had been proposed as an exclusive characteristic of human beings. It was something that, supposedly, made us unique. Today, it is added to the list of abilities that, in a more or less complex way, we share with other species, such as communication or memory.
“30 years ago it was not known if [chimpanzees] learned from each other,” explains Josep Call, a Catalan researcher at the University of St. Andrews, in the United Kingdom, and author of one of the works, in conversation with La Vanguardia. . “Now we know that yes, and that it is something that lasts generations, so we can say that they have culture, understood as a socially learned behavior and transmitted to different generations. The debate has moved to whether they have cultural accumulation,” he develops.
What Call, a psychologist who is an expert in primate cognition, says can be extended to other mammals, but also to insects, fish and birds. The point is that, until now, the cultural transmission of skills had been observed in the animal kingdom, but all of them were simple enough for an individual to acquire them on their own. Instead, cultural accumulation remained an exclusively human characteristic.
To test how true this idea is, the Catalan researcher has studied two groups of chimpanzees that live in semi-freedom in Zambia, and has published his results in the journal Nature Human Behavior. Call and his group left a ball and a box full of food for three months in the facilities where these animals live. To get food from the box, the chimpanzees had to take the ball, put it in a box and close it. Although they tried, they were unable to solve the puzzle, and after a few weeks they lost interest in the device.
After three months, the researchers taught the necessary steps to one individual from each of the groups of chimpanzees. When returned to their respective communities, these individuals acted as teachers and showed the steps to their peers. In the end, 14 of the 66 individuals studied were able to learn them and obtain the food.
The second work, published in Nature, did something similar with three colonies of bumblebees, a species whose brain is 0.0005% that of chimpanzees. In this case, the specimens had to move two levers to access a prize, something they were unable to learn by themselves after trying three hours a day for 24 days. Again, when the scientists taught the process to nine bumblebees, five of the 15 that did not yet know it learned to solve it.
In both cases, chimpanzees and bumblebees were able to copy a partner to acquire a skill that had been impossible for them to develop on their own. Consequently, the experiments demonstrate that cultural accumulation is not an exclusively human characteristic, a hypothesis that, in fact, was proposed by Josep Call himself, together with other colleagues, in 2009.
In the expert’s opinion, however, the findings do not completely refute this idea, but rather qualify it. On the one hand, because they do not evaluate specimens in the wild, which tend to be more cautious and less curious than captive ones, so it remains to be seen if the findings reflect natural behavior.
On the other hand, Call points out, “do we want to reduce the cumulative culture that humans have to what chimpanzees do? “A fundamental aspect of cumulative culture in humans is that there is more than one individual involved.” That is, we can learn skills from two different people and combine them. “Our disciples are better positioned than us, there is progress,” and this has not yet been seen in chimpanzees or any other animal, she explains.
Captivity, together with the small samples of both experiments, constitutes the main limitation of the work. Also the limited—albeit long—time that the researchers gave the animals to investigate on their own.
“How can a researcher be satisfied that a task is too difficult for [a species] to solve alone?” asks Alex Thornton of the University of Exeter, in an analysis of the articles also published in Nature. The researcher focuses on the fact that “cognitive abilities, skill, and knowledge vary widely among individuals of a species,” which makes it difficult for him to generalize that a behavior is impossible to acquire individually from a sample of individuals.
These generalization difficulties, in fact, are an example of the criticism that Call has faced since he proposed his hypothesis in 2009. “Detractors of the hypothesis had said that it was impossible to prove. I had always defended that it is evidently testable,” she concludes.
With all the nuances, the findings reopen the debate of whether there is a single ability that makes us human, or if it is the combination of various factors that has allowed us to build the complex culture on which we depend.
Call does not doubt that there are unique abilities of human beings, which are combined with a greater development of other common ones such as language or culture. “The fun part is seeing what the similarities are, and what the differences are,” she concludes. To solve this puzzle, there is still a lot of research to be done.
