I’m so tired, so god-darn tired.
— Ernest Hemmingway, The Old Man and the Sea
“What we found was unexpected,” says Abe. The birds reacted to only one of the four jumbled versions, called SEQ2, as if they noticed it violated some rule of grammar, whereas the other three remixes didn’t. Almost 90 per cent of the birds tested responded in this way. “This indicates the existence of a specific rule in the sequential orderings of syllables in their songs, shared within the social community,” Abe told New Scientist.
In subsequent experiments Abe showed that the rules were not innate – they had to be learned. Birds raised in isolation failed to react to SEQ2 until they had spent two weeks with other birds. He also taught birds unnatural grammatical rules by habituating them to one of his jumbled versions, then gauging their reactions to remixed versions that violated the “artificial” rules.