WHEN AI PRESSES the touch-sensitive computer screen, the Arabic numerals 1, 3, 5, 7 and 9 pop up in random order. She correctly taps the numbers in ascending order, earning a handful of raisins as a reward. Ai, a chimpanzee, also reveals a lightning-fast short-term memory for numbers. When white boxes mask the numerals right after each is displayed, she still strikes the boxes accurately—unlike some of the human volunteers who take the test.