Experiment 1, older jays, task 15, search following successive invisible displacement. One mealworm was already hidden under the first screen (left side) before beginning the test. Then, a second mealworm was visibly placed in the palm of the experimenter's hand, which was then closed. The hand passed behind two screens (closed) but the second object was placed inside a glove that the experimenter was wearing on his hand without being seen by the bird. The bird was led to believe that the mealworm was under the third screen (right side). Successful criterion: the jay searched systematically in reverse order, i.e. final screen, second screen and first screen.