The explanation:
This tells Japanese scholar Tetsuro Matsuzawa "that he has an actual picture memory, an eidetic memory. ... He takes a picture with his mind and holds it." Even if he turns away from the screen to do something else, the information stays in Ayumu's head. "You and I," says Matsuzawa, "we cannot do this. ... It is something special for the chimpanzee mind. It is not a matter of training for them. It is their way of seeing the world."