People remember things that are important to them, and are used often. I still remember five phone numbers from when I was a kid--my own, and friends-- even though I haven’t used them since then. I used them many times per week then, though.

Today, we carry around a “little black book” of numbers in our pocket along with our computer-phone. No one remembers birthdays, anniversaries, store hours, or even how to get to the doctor’s office, because we’ve off-loaded all of that to our computer-phones. It’s no wonder most people feel panic when they realize they’ve left their phone at home, or the battery dies because they didn’t charge it. That really should be worrisome, but everyone does it now, and it’s normal. It’s normal that no one bothers to remember anything they can find on their phone. What would you do without your phone for a week?

Since Hal can just look on the back of the box he has in his hand for the directions, he has no motivation to attempt to memorize them. He could memorize them, he just hasn’t made the effort, since it’s not important.