Not only humans and many mammals develop cultural traditions, birds also learn from each other. Now, an experiment with great tits shows that they can change and adapt their behavior once they have been established. This cultural progress is driven in a special way by immigrants – animals who still have a fresh eye for possible solutions to problems.
Our culture is formed by learning social behavior from our fellow human beings. And animals can do that too: for example, the chimpanzees that are related to us display human-like rituals that differ between groups living separately. Behaviors are also known in whales and dolphins, rodents and birds that are passed on from generation to generation within a population.
This is also the case with great tits in a British city, for example, who learned to open the sealing film on milk bottles in order to get to the layer of cream underneath. Over the course of 20 years, this “trick” spread among great tits across the UK. Other experiments confirmed that great tits pick up on cultural traditions and then maintain them: When individual animals were taught a new behavior, it was picked up by other, untrained birds and gradually spread within the populations studied.
Can tits change their cultural behavior?
However, it was previously unknown whether animals can change and develop such cultural traditions afterwards. That is why scientists working with Michael Chimento from the Max Planck Institute for Animal Behavior have now tested this in an experiment with great tits. The researchers tested whether and how great tit populations kept in the laboratory change socially learned foraging behavior when wild animals migrate. Since wild great tits live in variable social associations in harsh environmental conditions in winter, the researchers suspected that immigration could play a role in changing behavior. “Due to their lack of experience with the cultural traditions of the group, immigrant conspecifics could have a more unbiased view of possible solutions to existing problems and thereby influence cultural change within the group,” explains Chimento.
For their experiment, the team formed 18 bird groups with six animals each, each of which had access to a puzzle box with food reward. As soon as a bird pushed a door and thus got to the food, the identity of the animal, the type of solution and the required solution time were recorded with the help of an RFID transmitter and infrared technology as well as computer-aided image processing. Each group of birds had a “tutor” who was trained in a comparatively inefficient solution to the riddle, which then spread throughout the group. Over a period of four weeks, the researchers in half of the groups gradually exchanged two group members for new wild-caught animals from forests around Constance and then observed how and how quickly the bird groups solved the puzzle in contrast to the comparison animals .
Customized solutions
It turned out: In the bird groups, there actually seems to have been a cultural advancement through the immigrating great tits. In the course of the experiment, 17 of the 18 groups developed a more efficient solution for the puzzle than the one previously learned. However, the likelihood of adopting the more effective method as the preferred behavior in the longer term was significantly higher in the populations with the new great tits. The research team observed that the original group members, who were already familiar with the puzzle task, usually developed the improved solution for the task, but did not accept it as their preferred solution. Instead, it was mainly the inexperienced newcomers who picked them up as new behavior.
“The immigrants chose new, efficient behaviors disproportionately in relation to the available social information,” said the research team. As a result, the immigrants spread the more effective behavior and their group was able to solve the puzzle faster than the comparison groups in the end, although they had less experience overall. The latter only used the efficient solution around 1,500 times, the groups with the immigrants, on the other hand, around 40,000 times and needed 30 milliseconds less for the puzzle.
Immigration as a driving force
The change in the composition of the population, the so-called “population turnover”, seems to be decisive for a change in existing traditions in animals, conclude Chimento and his colleagues. According to the scientists, the immigration of the wild great tits is the driving force behind cultural development. “Experimental evidence of cultural change in animals is very rare,” says Chimento. “We were therefore surprised and enthusiastic about the results of our study.” And the cultural change of the tits obviously brings a survival advantage: “Compared to other species, great tits seem to get along well in human-made habitats”, the lead author sums up. “Our study shows how their changing social dynamics could be part of their secret of success and contribute to their adaptability.”
Presumably, the “population turnover” could be a general mechanism for the evolution of culture in the animal world and is possibly also a forerunner of the human cultural system, the researchers suspect. In future studies, they want to investigate whether immigrant individuals can also be innovative themselves and can pass on more efficient behaviors to the existing group.
Source: University of Konstanz, Article: Current Biology, doi: 10.1016 / j.cub.2021.03.057