PEOPLE may use the expression "birdbrain" in English to talk about someone who is stupid, but crows prove that this is unfair. Now it has been discovered that crows may understand analogies  . To test this ability in animals, scientists do "relational matching-to-sample (RMTS)"tests. If a pair was AA, for example, then picking BB to match it would be correct. An international team led by Edward Wasserman in the US first trained two crows to match things by color1, shape, and number in what is called" identity matching-to-sample (IMTS)" , then moved onto RMTS. For the IMTS test, the birds were put in a cage with a plastic tray that had three cards and two cups in it. The card in the middle was the sample card. The cups on either side were covered with the other two cards. One was the same as the sample, while the other wasn' t. The cup with the card that matched the sample card contained two worms to eat. In the second part of the experiment, the birds were tested with relational matching pairs. A card with two same- sized circles, for example, meant they should pick the test card with two same-sized squares and not two different-sized circles. The birds did well in the more difficult test and picked the correct card more than three quarters of the time. Wasserman was surprised that crows were able to solve the problem without any training in RMTS. He said in a news release: "Honestly, if it was only by force that the crows showed this learning, then it would have been an impressive result. But this was spontaneous." So perhaps it' s time to stop saying " birdbrain" permanently. Which of the following can be the best title for the text?
Crows show cleverness. Crows may understand analogies. Crows did well in RMTS. Apes and monkeys are cleverer than crows.