How Do We Retain What We Learn?

The best answer to any question.
April 14 2014 11:09 AM

How Do We Retain What We Learn?

Students in Brooklyn, N.Y., build robust neural networks in April 2014.

Photo by Spencer Platt/Getty Images

This question originally appeared on Quora.

Answer by Robert Frost, engineer and instructor at NASA:


Retention means being able to easily access the information later. To do that, one wants to have that information in a neural network that is robust and well indexed. To do that, one needs to ensure the following during learning and after:

    1) Repetition
    2) Connection of new information to old information

When we repeatedly think about something, the related neurons grow tentaclelike structures called dendrites that reach out to connect to other neurons. If we continue to think about that item, those dendrites can acquire redundant dendrites that grow alongside them, and the receptor sites on those dendrites can acquire greater throughput.

We can analogize this to a road system. If we build six-lane highways to a destination, it's easier and faster to get there than if we have dirt trails.

Our brain organizes the information it acquires and continues to reorganize to optimize storage and recovery of that information. By connecting new information to older information, we make it easier to find that information later.

We can analogize that to having a road map. If we have a map, it's easier to get there than if we don't—or remembering that the new shoe store is next door to the old bookstore that we've repeatedly visited.

We rarely lose information within our brain; we just make it harder to find when we need it. Good retention of learning means making robust pathways to find that information and organize it well.

When things have been well-indexed and repeated sufficiently, they become automatic, meaning we can recall them without conscious effort. The alphabet is an example. We have repeatedly used that information so often that it is so easy to access that we don't have to think about it.

Stop thinking about something and those dendrites can shrivel up, becoming less effective, like an unmaintained road. So, even after we think we've fully learned something, we still need to periodically use that information if we want it to remain easy to access.

More questions on Human Memory:



The Irritating Confidante

John Dickerson on Ben Bradlee’s fascinating relationship with John F. Kennedy.

My Father Invented Social Networking at a Girls’ Reform School in the 1930s

Renée Zellweger’s New Face Is Too Real

Sleater-Kinney Was Once America’s Best Rock Band

Can it be again?

The All The President’s Men Scene That Captured Ben Bradlee

Medical Examiner

Is It Better to Be a Hero Like Batman?

Or an altruist like Bruce Wayne?


Driving in Circles

The autonomous Google car may never actually happen.

The World’s Human Rights Violators Are Signatories on the World’s Human Rights Treaties

How Punctual Are Germans?

  News & Politics
Oct. 22 2014 12:44 AM We Need More Ben Bradlees His relationship with John F. Kennedy shows what’s missing from today’s Washington journalism.
Oct. 21 2014 5:57 PM Soda and Fries Have Lost Their Charm for Both Consumers and Investors
The Vault
Oct. 21 2014 2:23 PM A Data-Packed Map of American Immigration in 1903
  Double X
The XX Factor
Oct. 21 2014 3:03 PM Renée Zellweger’s New Face Is Too Real
  Slate Plus
Behind the Scenes
Oct. 21 2014 1:02 PM Where Are Slate Plus Members From? This Weird Cartogram Explains. A weird-looking cartogram of Slate Plus memberships by state.
Brow Beat
Oct. 21 2014 9:42 PM The All The President’s Men Scene That Perfectly Captured Ben Bradlee’s Genius
Oct. 21 2014 11:44 PM Driving in Circles The autonomous Google car may never actually happen.
  Health & Science
Climate Desk
Oct. 21 2014 11:53 AM Taking Research for Granted Texas Republican Lamar Smith continues his crusade against independence in science.
Sports Nut
Oct. 20 2014 5:09 PM Keepaway, on Three. Ready—Break! On his record-breaking touchdown pass, Peyton Manning couldn’t even leave the celebration to chance.