In their experiment, this exchange window was covered up and closed on one bird's cage, making it impossible for that bird to trade. The bird had a pile of tokens in its cage but no way to use them. Meanwhile, its neighbor in an adjacent cage had an open exchange window — but no tokens for food.
After sizing up the situation, the token-rich bird would help out its pal by passing tokens through an opening between the two bird enclosures. And the bird shared even though it didn't partake in the walnut payoff.
"The African greys gave the token beak-to-beak with their partner," Brucks says. "It was not just one token. Many of them transferred all 10 tokens, one after the other, always watching how their partner got the food for it, whereas they themselves did not get anything."
Later, scientists reversed birds' roles to see if the recipient of this generosity would pay back those favors. And the birds did.
"In the very first trial, they could not have known that the roles would be reversed afterward," says Brucks, who notes that the parrots seemed to have an intrinsic desire to help out their partner. The eight birds tested all knew each other and lived in the same social group.
It seems that the birds weren't just being playful with the tokens, but really understood when and why the token was needed. That's because the birds would rarely pass a token over if the neighbor bird's exchange window was closed up.
This study is a starting point to explore what exactly is going on in the birds' minds, Brucks says.
A similar study in ravens did not find this effect. And when Brucks tested blue-headed macaws, they weren't helpful either. The macaws tried to bring the tokens as close as possible to the experimenter but did not transfer the token to the partner, Brucks says.
"We are really interested in this topic, and it's an important topic. The problem is it's very, very hard to design an experiment to truly demonstrate what is truly going on with these animals," says Irene Pepperberg, a Harvard researcher whose work with a famous African grey parrot named Alex helped reveal the sophisticated cognitive abilities of these birds.
Pepperberg has also done experiments to test African greys' willingness to help, using a different setup, and found that one parrot appeared to have some understanding of sharing — but it didn't seem like the parrots were spontaneously super-altruistic.
Still, Peggy Mason of the University of Chicago believes that this new study in parrots is striking.
"When they gave the token, the other bird was getting the food and they were not," Mason says. "I think they had the sense that this was a useful token, and that this token would turn into food for the other bird. It's very shocking. It's surprisingly giving, just because the only thing the bird doing it gets is that warm glow of helping."
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