Which decision has more chance of success? If we do not know something for certain, we use probabilities as a basis for such questions. Surprisingly, New Zealand’s mountain parrots are also capable of this wise calculation, a study shows: The clever birds understand whether something is more or less likely and adjust their behavior accordingly. In their calculation, they can include quantitative relationships and even social information. So far, such high cognitive performance was only known by humans and great apes, the researchers say.
Eight blue and two yellow balls – if someone blindly reaches for one of them, what color are they most likely to catch? It will probably be a blue ball, the mind tells us. This may seem banal, but from a cognitive research perspective, capturing statistical probabilities is a complex feat of our brain. This calculating mind is very important for human behavior: Despite uncertainty, we can make decisions that have comparatively high chances of success. This ability to detect and use probabilities develops comparatively early in humans: Studies have shown that even small children calculate. In animals, however, this ability is only known from our closest relatives – the great apes.
Feathered “smarties” in the test
Amalia Bastos and Alex Taylor from the University of Auckland have now explored whether Keas is also capable of this intelligence achievement. These parrot birds from the mountain regions of New Zealand were promising because they have already demonstrated their amazingly sharp minds in various behavioral studies: they can solve complex problems, use tools and there is even evidence that they recognize themselves in the mirror. “It is a lot of fun to work with these animals because they have such distinctive personalities,” says Bastos.
As part of their study, the researchers first taught some keas to use a kind of currency: if they give the experimenter a black wooden stick, they will get a treat in exchange. Objects of a different color, on the other hand, have no “purchasing power”, the birds quickly learned. In one of the experiments, the scientists presented the animals with two transparent vessels containing mixtures of black and orange sticks. In one, the orange sticks were represented in the mix, in the other hand the black sticks were more common. The experimenter now reached into both vessels at the same time and invisibly gripped a staff with his fist. Then the bird should decide by pecking which fist it wants to get the object from.
It turned out that the Keas chose the hand that reached into the vessel, which contained more black than orange sticks. The animals had apparently understood that this choice made them more likely to get one of the coveted black exchange items. In a further experiment, the researchers increased the complexity of the challenge: there was a clearly visible separating layer in the vessels. As it turned out, the birds now based their decision on whether the section accessible when gripping contained more black than orange objects.
Statistical probabilities in your head
In another experiment, the researchers investigated whether the keas could also include social information in their calculations. They first learned that there are certain people who have a preference for black sticks: some investigators deliberately took a black exchange object from the mixtures a little more often than others and gave it to the birds. In subsequent experiments, the researchers were able to show that the animals selected the closed fists of these people more often than those of others who had not shown this tendency. According to the scientists, the keas can also link probabilities with the behavior of certain individuals.
There are thus astonishing parallels in the cognitive abilities between these intelligent birds and humans or apes. From an evolutionary biological point of view, too, this is an interesting finding, the researchers say. It is estimated that human and kea lines of development separated 312 million years ago. This is also reflected in the significantly different structure of the brains of birds and mammals. Nevertheless, both versions of the nerve organs were ultimately able to produce similarly complex skills, as the current study shows.
The researchers now want to continue exploring the level of understanding the keas are still capable of. “The Keas can always surprise us. I’m excited to see what else they can do, ”says Bastos.
Source: Nature Communications, doi: 10.1038 / s41467-020-14695-1