Overview: Examine some factors that affect short-term memory
Learning Goal: Understand that short-term memory decreases quickly over time and that certain factors can increase or decrease recall
Video Link: Understanding the Brain, A New Synthesis
Advances in technology have enabled scientists to explore questions about the brain that were unanswerable a century ago. PET scans, for example, help researchers identify regions of the brain that are active during specific cognitive tasks, such as memory recall. Students can investigate short-term memory in this activity to examine some factors that increase and decrease recall.
1. Announce to students that it's time for a test -- of short-term memory! Their challenge is to recall items from a list they will hear twice.
2. Divide the class into four numbered groups. Have each student write his or her group number on a sheet of paper.
3. Read aloud each item from the list. Read slowly and clearly, pausing for several seconds after each item. For nonsense syllables, pronounce each one and then spell it (e.g., "tig: t-i-g"). Shout the word NAV as loud as you can; then spell it in a normal speaking tone. Read the list the same way a second time.
4. Immediately after the second reading, ask students in Group 1 only to write down every item they can remember. Each student should do this independently.
5. Conduct class as usual. Five minutes after the second reading, ask Group 2 students to record all the items they remember. About 15 minutes after the second reading, ask Group 3 to do the same. At the end of class, have Group 4 write down all the items they recall. Collect the lists.
6. At the next class, assemble students into their groups. Return each group's word lists along with the actual list. Ask students to analyze their performance as a group. Have each group find the average number of items recalled and rank the words in order of the frequency of recall. Ask each team to brainstorm factors that might have affected recall.
7. As a class, graph the average number of words recalled by each group against the length of time between reading and recall. Discuss the resulting curve. What does this "forgetting" curve imply about the capacity and persistence of short-term memory?
8. Ask students to compare the groups' rankings of items most frequently remembered or forgotten, and compile a classwide ranking. Why were some items recalled more frequently than others? Consider, for example, the sequence of items on the list. Were items near the beginning, middle, or end more likely to be remembered?
9. Based on this activity, have students develop at least two hypotheses about short-term memory and cite evidence that supports them.
Meaning enhances memory. One way to make information meaningful is to put it in context. Divide the class in half, and tell only one half the context for the sentences they will all hear: fishing. Read the sentences (see below) aloud. When you're done, ask students to write down each one they remember. Then, read the sentences again. Have them check the number they recall accurately (not necessarily word-for-word). Compare responses. How did having a way to mentally organize information affect memory? Why is it so hard to remember a series of unrelated statements? How could students use this principle to improve study habits?
Rainy days are better than sunny days. It's hard to find a good place in the city. You'd be surprised what a nuisance seagulls can be. The earlier you get up, the better. Books can't teach you everything. Cleaning is usually pretty messy. If you can't swim, wear a lifejacket. A good book or a radio helps to pass the time. Some people like worms; some like bugs. Lemon juice takes away the smell.
Mapping the Mind
Neurologist Wilder Penfield was one of many scientists to try to pinpoint mental functions such as memory to certain parts of the brain. In this photo he has just drawn the brain map simultaneously with both hands!