You’ve spent the day at a leadership conference learning all sorts of great things: how to coach your team, how to build engagement, how to run effective meetings, how to encourage career development, and more. You go back to work the next day with good intentions—but quickly lapse into your old habits. Within a few weeks, you try to recall what you learned, but even with your notes, you have a hard time. What on Earth happened? If he were still alive, 19th-century psychologist Hermann Ebbinghaus would have the answer: You just experienced the “forgetting curve.” We’ve known for 126 years