Entrepreneur and author Ben Casnocha tells the story of a speech given by Mark Zuckerberg. With a legion of young entrepreneurs packed into the auditorium, the Facebook CEO shared lessons from his journey and offered his perspective on the state of the internet industry.

Among those in attendance were John Doerr and Ron Conway, two of the most successful investors in Silicon Valley. But they didn’t stand out because they were several decades older than the average attendee. They stood out because they were the only people in the audience taking notes.

“Isn’t it funny,” Casnoscha says, “that arguably the two most successful people in the room after Zuckerberg were also the only two people taking notes?”

It’s been said that the faintest ink is more powerful than the strongest memory. And most of us, when we do take notes, do so for that exact reason—we don’t want to forget critical information.

But there’s another important, less prevalent reason for taking notes. One that I learned while reading Charles Duhigg’s book, Smarter Faster Better: “Sometimes the best way to learn is to make information harder to absorb. This is known in psychology as “disfluency.” The harder we have to work to understand an idea or to process a piece of data, the stickier it becomes in our brain.”

Duhigg goes on to tell the story of researchers from Princeton and UCLA who looked at the difference between students who took notes by hand and those who used a laptop.

When the researchers looked at the test scores of those two groups… they found that the hand writers scored twice as well as the typists in remembering what a lecturer said. The scientists, at first, were skeptical. Maybe the hand writers were spending more time studying after class?

They conducted a second experiment, but this time they put the laptop users and the hand writers in the same lecture and then took away their notes as soon as it was over, so students couldn’t study on their own. A week later, they brought everyone back. Once again, those who took notes by hand scored better on a test of the lecture’s content.”

No matter what constraints were placed on the groups, the students who forced themselves to use a more cumbersome note-taking method—who forced disfluency into how they processed information—learned more.

I recently attended a two-hour training at work. A few minutes into the presentation, the facilitator told us we didn’t need to take notes; she would send out the slide deck. The few who were taking notes immediately put their notebook away. I normally would have done the same, but I kept writing.

I had just finished reading Duhigg’s book, and had made a commitment to bring a notebook to every meeting I attended, regardless of the content. Over the last few months I’ve kept up with this habit. My notebook comes with me from meeting to meeting, and I make the effort to jot down what’s being discussed. This practice both increases my learning and helps me stay engaged. More importantly, I better retain the information I’ve learned.

If you aren’t regularly taking notes, I challenge you to give it a try. Like the Silicon Valley investors during Zuckerberg’s address, you may be the only one in the room taking notes. But the process of putting pen to paper, because it requires effort, will lead to greater comprehension and knowledge.