Key concepts
Psychology
Learning
Memory
Brain

Introduction
If someone tells you to remember a phone number or address, it can feel like an easy task at first. You repeat the numbers to yourself, either aloud or in your mind. But after just a few seconds you might find yourself starting to doubt your own memory. Was it 5-7-3 or 3-7-5? Our brain is always seeking new and useful information, and as a result it will try to throw away information that seems old or irrelevant, such as a random string of numbers or an address. There are ways of helping our minds retain information, however, and in this activity you will explore ways that we lose and keep memories.

Background
Short-term, or working memory, is a way of describing most people’s abilities to store a small amount of information for a brief period of time in a readily accessible form. Short-term memory has a short duration (thought to be on the order of seconds or minutes) but is quickly and easily accessed. People don’t have to stop and think to remember something in short term memory—they can access it quickly and easily.

There are many techniques for improving memory retention (capacity to store information over time). Such techniques include visualizing the information in a surprising way or linking pieces of information together so that one reminds you of the other. In the case of visualizing information this could be as simple as remembering you parked your car on the fifth floor in the D section by picturing five dogs sitting in your car! In addition, linking information could help you remember your grocery list. If you need to purchase cereal, milk, fruit, cheese and eggs, you could imagine the cereal in a bowl, with milk pouring over it and pieces of fruit on top. Then imagine cracking an egg over everything, and it’s full of melted cheese! These may seem simple or even silly, but they are time- and scientist-tested for improving memory retention. In this activity you’ll test the recall of a few friends or family members, and learn a few tricks for improving memory!
 

Materials

  • Piece of paper
  • Pen or pencil
  • At least four volunteers
  • Quiet place to test your volunteers
  • Clock or timer
     

Preparation

  • Use your pen and paper to create a table with five columns and five rows. Label the columns’ top boxes accordingly:
  • first column: “Volunteer Name”
  • second: “Single Digit 1 Minute”
  • third: “Single Digit 2 Minute”
  • fourth: “Multiple Digit 1 Minute”
  • fifth: “Multiple Digit 2 Minute”


Procedure

  • Test each of your volunteers individually, following the steps below. Make sure they don’t hear each other’s tests!
  • Start with Volunteer 1. Take them into the quiet space you’ve chosen for testing.
  • Write Volunteer 1’s name in the second row of your table, in the column “Volunteer Name.”
  • Tell Volunteer 1 that you’re going to be asking them to memorize four different sets of numbers. You will tell them the number sequence once, then wait a designated amount of time before testing how well they remember the number sequence.
  • When your volunteer is ready, read the 1 Minute Single Digit Number Sequence aloud to your volunteer: “4, 9, 1, 7, 2, 2, 6, 5, 8, 3.” As soon as you finish reading the sequence, start your timer. How many numbers do you think your volunteer will be able to correctly remember in the right order?
  • Make sure to stay quiet so you don’t distract your volunteer. After one minute has gone by on your timer ask your volunteer to repeat the sequence back to you. As they recite the numbers aloud, write down the numbers as they say them in the “Single Digit 1 Minute” column.
  • Tell your volunteer you’re going to read another set of numbers, and ask them to memorize and repeat them after a certain amount of time.
  • Read the next Single Digit Number Sequence aloud to your volunteer: “5, 0, 2, 8, 8, 3, 7, 6, 9, 4.” As soon as you finish reading the sequence, start your timer. Do you think your volunteer will be able to remember the same amount of numbers as in the one-minute test? Why or why not?
  • After two minutes have gone by, ask your volunteer to repeat the sequence back to you. As they say the numbers aloud, write them down as they repeat them in the “Single Digit 2 Minute” column.
  • Tell your volunteer you’re going to read a third set of numbers, and ask them to memorize and repeat them after a certain amount of time.
  • When your volunteer is ready, read the Multiple Digit 1 Minute Sequence aloud to your volunteer: “49, 17, 22, 65, 83.” As soon as you finish reading the sequence, start your timer. Do think your volunteer will have a more difficult or an easier time remembering these 10 digits?
  • After one minute has gone by, ask your volunteer to repeat the sequence back to you. As they say the numbers aloud, write them down as they recite them in the “Multiple Digit 1 Minute” column.
  • Tell your volunteer you’re going to read a final set of numbers, and ask them to memorize and repeat them after a certain amount of time.
  • When your volunteer is ready, read the Multiple Digit 2 Minute Sequence aloud to your volunteer: “50, 28, 83, 76, 94.” As soon as you finish reading the sequence, start your timer. How do you think your volunteer will do trying to remember these numbers in order?
  • After two minutes have gone by, ask your volunteer to repeat the sequence back to you. As they call out the numbers aloud, write them down as they say them in the “Multiple Digit 2 Minute" column.
  • Circle the mistakes your volunteer made in each column.
  • Repeat these steps with your remaining volunteers. (Make sure your next volunteers can’t see the numbers from previous volunteers on the paper.)
  • Add up the number of mistakes made in each column. Which column has the highest number of mistakes made? Which column has the lowest? Why do think that might be?
  • Extra: Try repeating the test, but instead of remaining quiet while your timer is going, ask the volunteer to sing a common song. Test what effect this has on their ability to repeat the number sequence.
     

Observations and results
You might have noticed the digits you read for the Single Digit and Multiple Digit number sequences were the same. For the Single Digit Number Sequence, however, you read 10 individual numbers whereas for the Multiple Digit Number Sequence you read five double-digit numbers. Although they contain the same number sequence each time, you might have noticed your volunteers found it easier to memorize the Multiple Digit Number Sequence. Your volunteers were able to remember the number “49” as one number whereas when you said it as “4, 9” they had to remember the numbers 4 and 9 as distinct numbers. To remember information such as number sequences, your brain uses its short-term memory storage. Your short-term memory has a limited amount of space to store information. As you fill it, there is less room to hold additional content. The number “49” takes up less space in your memory than the numbers “4” and “9” do separately. This is a memory technique known as “chunking,” and it can help you memorize longer sequences of numbers (and letters) by chunking them together.

You might have also noticed that more errors were made when the volunteer had to wait longer to repeat the number sequence back to you. Attention and time are extremely important to short-term memory function. As more time goes by, it’s more difficult to control our attention. Even when we try to focus on a piece of information such as a number sequence, retaining that information over longer periods of time becomes more difficult. This is sometimes referred to as the recency effect, where the more recently something was discussed, the easier it is to remember.

More to explore
Sentient Skills Science: What Makes Some Memories So Memorable?, from Scientific American
Study Skills Science: Investigating Memory Mnemonics, from Scientific American
Do the Eyes Have It?, from Science Buddies
Science Activities for All Ages!, from Science Buddies

This activity brought to you in partnership with Science Buddies

Science Buddies