![]() She and her colleagues suspect that ravens’ cognitive development must be fast-tracked because they begin interacting more with their ecological and social environment at about four months of age. “We didn’t expect that they’d master these tasks so quickly,” Pika says. They were surprised to find that by just four months old, the birds had mastered most tasks-to the point that, almost across the board, the young ravens’ results compared similarly to those of adult chimpanzees and orangutans that Herrmann had previously tested. The authors repeated the same 33 tasks for each raven at four, eight, 12 and 16 months of age. That task was an easy one for the raven it quickly found the cup with the bait and its just reward was forthcoming. Here, the experimenter switched the position of the cup that contained bait with an empty cup. Ravens understand that objects can change their locations. The human signaled which cup contained a reward by looking or pointing at it, for instance, or showed the ravens how to access a reward and then observed whether they were able to apply what they observed. ![]() Under the social test umbrella, the researchers measured how well the birds could follow cues given by an experimenter. For example, researchers placed a reward under a certain cup and then moved that cup around with several others to see if the ravens could track which one contained the reward. Physical tests measured the birds’ abilities to track objects in space and to understand numbers. “We tried to have many tasks in many domains to have a comprehensive understanding of what ravens can do,” Pika says. The assays consisted of nine physical categories and six social ones, which were individually comprised of up to four different tasks repeated multiple times each. Pika, Herrmann and their colleagues adapted and administered the same suite of tests to eight hand-raised ravens. Herrmann and other scientists have used her now well-established technique to make additional cross-species comparisons in monkeys, dogs and parrots. Herrmann’s method measures general performance across a range of social and physical tasks rather than just one specific aspect of cognitive reasoning, as most prior approaches did. ![]() In their new work, Pika and her colleagues turned to a large group of tests that study co-author Esther Herrmann of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, originally developed in 2007 to investigate cognitive performance in great apes and human children. “Across a whole spectrum of cognitive skills, their intelligence is really quite amazing.” The findings, published in Scientific Reports, add to a growing body of evidence indicating that impressive cognitive skills are not solely the domain of primates but occur in certain species across the animal kingdom. “We now have very strong evidence to say that, at least in the tasks we used, ravens are very similar to great apes,” says Pika, lead author of the study. The brainy birds performed just as well as chimpanzees and orangutans across a broad array of tasks designed to measure intelligence. “Quite often, in single tasks, you’re just testing whether the bird can understand that you’re hiding something,” says Simone Pika, a cognitive scientist at Osnabrück University in Germany.Ī new study that that tries to address that deficit provides some of the best proof yet that ravens, including young birds of just four months of age, have certain types of smarts that are on par with those of adult great apes. But most studies use single experiments that provide a limited view of their overall intelligence. Scientists and casual observers alike have known for years that ravens and their corvid relatives are extremely smart. ![]()
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