Memory is reconstructive, not photographic—you'll remember the Apple logo wrong despite seeing it thousands of times. Dr. Alan Castel reveals how retrieval failure, curiosity, and deliberate practice stamp memories into long-term storage, and why some people maintain sharp cognition into their 90s while others decline earlier. Errorful learning through retrieval failure followed by correction produces better long-term memory than passive repetition, even when people don't get the answer right initially.