"Learning has an evolutionary purpose: Among species, individuals that adapt to their environments will succeed. That's why your brain more easily retains important or surprising information: It takes very little effort to remember that the neighbor's dog likes to bite.
The forgetting curve shows how brains are different. They can learn anything, which means they need to filter out the important from the trivial. Luckily, understanding how the curve works makes it easier to learn things that may not be necessary for survival, but are deeply rewarding. Like a new language, a musical instrument, or the name of Chewbacca’s father (it’s Attichitcuk)."