[two] Alex handed more and more challenging checks measuring irrespective of whether human beings have obtained Piaget's Substage six item permanence. Alex showed surprise and anger when confronted with a nonexistent object or one diverse from what he were brought about think was hidden throughout the tests.[16] Study this https://primarycaremedstore.blogspot.com/2023/09/exploring-macaw-and-grey-parrot-shop.html