Because ravens typically do not use tools in the wild, and bartering is not one of their known natural behaviors, the findings provide evidence that these birds possess complex cognitive skills that can be flexibly applied to novel situations. Their brain power includes reasoning, drawing from both long and short-term memory and, at times, exhibiting restraint.
Great apes, such as chimps and gorillas, possess similar skills, but monkeys previously flunked tests that ravens could ace. Even human kids must be at least 4 years old in order to achieve certain cognition and behavior feats, with control of impulsiveness being particularly challenging, as many parents with youngsters in the “terrible twos” might observe.
Kids, as well as ravens, require time to learn that restraint can often be beneficial. Considering that the average lifespan of a raven in the wild is just 10–15 years, their cognitive achievements are all the more remarkable.
Regarding raven memory, prior research found that a “raven can remember a single encounter with a human for at least a month,” so “they can remember information for a very long time,” Osvath said.
For the new series of experiments, Osvath and Kabadayi first trained the ravens to use a tool, which again was a stone, to open the puzzle box in order to access a food reward. The ravens were then presented with the box, but not the tool. The box was subsequently removed.
RELATED: The Number of Bird Species Could Be Double What We Thought
One hour later, the ravens were presented with the tool, as well as several toy “distractors” that were too large to fit into the slot of the vending machine-like puzzle box. The distractors included a wooden wheel, a wooden ball, a T-shaped metal pipe and a plastic toy car. Nearly every raven chose the correct, apparatus-opening tool, with a success rate of 86%.
A high success rate (78 percent) was also seen in similar experiments where ravens used a token — a blue plastic bottle cap — to later barter for a food reward. The ravens planned for bartering more accurately than apes have done in earlier studies, the researchers reported. The birds even began to store their tokens, like saving money, for future trades.
Finally, the ravens were presented with the correct, apparatus-opening tool, distractor tools, and an immediate food reward, but were only permitted to select one item. The ravens demonstrated self-control on par with great apes by opting for the tool, which eventually earned them a better food reward than the immediate treat.
The study only looked at ravens, but it is possible that other corvids, such as crows and scrub jays, possess similar — if not equally impressive — smarts.