Trenton was playing in a sandbox. He was pouring sand from a short and wide container into a tall and narrow container. When he poured the sand into the tall and narrow container, it appeared as if it had more sand in it. Trenton could not figure out where the extra sand came from and how it got into his container. As Trenton continued to try to solve this puzzle, he experienced considerable movement between states of cognitive ________ and ________ to produce cognitive change.