Copyright © 2007-2017 Russ Dewey
Students studying for an exam do not have the luxury of waiting weeks or months between repetitions. Fortunately, they may not have to.
Nelson and Dunlosky (1991) studied judgments of learning as people's estimates of how well they learned something. Nelson and Dunlosky found that judgments of learning (JOLs) were "extremely accurate" when the JOL was "delayed...rather than being made immediately after study."
Even after a short delay people were good judges of how well they had learned something. But they were not accurate when asked immediately after reading something.
What did Nelson and Dunlosky discover about JOLs? What are the implications for students?
The JOL (judgment of learning) concept definitely is relevant to students studying for college-level coursework. You must be able to judge your own learning to decide when you have studied something enough and can move on.
However, the Nelson and Dunlosky study shows this cannot be determined immediately after reading. If you want to judge your own learning, you must wait for a minute or two after you have studied something.
Turn your attention to something different. After emptying your primary memory, go back to your study material and ask yourself if you remember what you were just studying.
As long as you wait for short-term memory to clear out, you will make accurate judgments about whether you remember what you studied. Then you can take appropriate action, moving on or re-studying the material as appropriate.
How does the JOL study relate to advice in Chapter Zero?
The JOL research explains why I called the study procedure of looking back and forth between study questions and answers "Dead Wrong" in Chapter Zero. That procedure does not allow accurate judgments of learning.
A person can get the impression he or she has learned something because the material lingers in working memory. That feeling can be misleading.
Only by clearing out working memory and then interrogating long-term memory can you determine if you have learned something. After you read, go take a break (like the student in Chapter Zero who always listened to a 30 second Counting Crows song before reviewing his study questions.) Then, and only then, come back and see if you can answer the study questions.
Ebbinghaus, it seems, did not believe some of his own data. His forgetting curve dropped off steadily except for one period of time: between 8 and 14 hours after learning.
During those six hours the curve was completely flat, showing no forgetting. Ebbinghaus wrote, "Such a relation is not credible" and rejected the data, blaming it on accidental errors in his experiment.
Why did Ebbinghaus reject some of his own data?
Jenkins and Dallenbach (1924) thought Ebbinghaus made a mistake by rejecting the idea (which Ebbinghaus briefly considered) that sleep reduced the amount of forgetting. There was no big drop-off in retention between 8 and 14 hours because Ebbinghaus was asleep then.
Jenkins and Dallenbach tested this idea with students. They taught students nonsense syllables around midnight, right before bed, or early in the morning before their classes.
The results were clear. Students remembered more if they slept during the retention interval instead of attending classes. No doubt this led students of the 1920s to make jokes about the virtues of staying in bed and skipping classes.
How did Jenkins and Dallenbach explain the Ebbinghaus observation?
Jenkins and Dallenbach thought their findings for an interference theory of forgetting. They assumed the brain was resting during the night, so there was less interference, and the memory persisted.
We now know the brain is very active during sleep. Something else was happening during sleep to improve memory.
Many students report that, after intense studying right before going to bed, they spend the night dreaming about bits and pieces of the material they studied. In one experiment, subjects played the computer game Tetris. The following night they were awakened during sleep, and most reported dreaming about the images of bricks falling into place.
Such "bits and pieces going through the mind" may be the subjective accompaniment of important memory-enhancing brain processes. Rather than being a blank time, sleep may be a time of helpful information processing.
Why might it be a good idea for students to study right before going to sleep?
In one early experiment on reactivating memories during sleep, Wilson and McNaughton (1984) made recordings from large numbers of hippocampal "place cells" in rats.
Place cells are known to fire in correlation with a rat's location. The cells were monitored while rats learned to find food in a T-shaped maze. Then the rats were allowed to sleep, while the same cells (and many others) continued to be monitored.
Some of the place cells fired together (synchronized) when the animal occupied particular locations in the maze. Those cells also showed synchrony during subsequent slow-wave sleep, while other neurons (not activated during the learning task) did not. The correlations gradually disappeared during following sleep episodes.
Variations of this experiment were repeated many times by other researchers. The cumulative results suggested rats were reliving a successful run through a maze in their non-REM sleep.
Other researchers showed that memory for experimental tasks improved if animals were allowed to sleep or rest during the night instead of being kept up and active. This was true for all species tested, even fruit flies.
When is this advice most likely to work?
The obvious conclusion is that students should study right before going to sleep. But what about adrenaline? Adrenaline aids memory formation. Many people are low in adrenaline before going to sleep.
Perhaps the "study before you sleep" effect is best used during final exam times or before a big test, when all distractions are put aside (or should be) and there is adrenaline due to the stress. In these conditions, the material studied before bedtime is likely to circulate in the mind all night, perhaps growing stronger in the process.
Craik and Lockhart (1972) suggested the term deep processing to describe the type of mental activity that improves memory. The idea was immediately appealing.
Experiments showed that superficial processing such as maintenance rehearsal was ineffective at improving memory. Deep processing was operationally defined, in studies of word list retrieval, by having subjects inspect words for meaningful relationships to other words. That produced excellent recall of word lists.
What was the depth of processing concept and how did it run into trouble?
The concept of deep processing ran into trouble when researchers tried to specify exactly what it meant. As noted in Chapter 1 a psychological construct is validated or given substance by finding independent ways to measure the same thing.
Deep processing was defined as processing that produced better memory. However, it turned out different types of processing produced benefits for different tasks.
If subjects needed to remember the physical appearance of a word, then paying attention to the shape of the letters was important. If subjects needed to recall the sound of a word, then paying attention to sound was most important, and so forth.
This led to another concept: task appropriate processing. That is information processing appropriate to the task at hand, so it is a relative term.
How can students engage in task-appropriate processing?
What if your task is to study for a quiz? What is the deepest or best form of processing? It depends on the quiz and what it asks you to do. If the quiz requires you to answer questions, then you should practice answering questions.
If you are preparing for an essay test, you should practice writing essays. If you are preparing to answer story problems, you should prepare by practicing on story problems.
Students quickly psych out the way a teacher writes tests. This affects how they study.
A similar point was made earlier in the section on recognition memory. If a teacher gives multiple choice tests which require only the recognition of vocabulary words, students learn to familiarize themselves with vocabulary from the chapter and little else.
If questions require deep comprehension of the material, students are more likely to strive for deep comprehension. Once they learn what to expect on a test, most students will adopt a strategy of task appropriate processing.
One way to organize memory for later retrieval is to draw up a summary of it that provides cues for recalling more detailed information. Tulving (1974) explained that forgetting is due to the absence of appropriate retrieval cues.
Tulving's statement is consistent with the idea that retrieval is the weak link in memory. When we forget something, it is not because the memory is gone forever.
Memories are lost when we do not know how to retrieve them. If we are given a reminder (a cue) the memory comes back.
What causes forgetting?
The best way to overcome forgetting is to develop a system for generating your own cues. Clever teachers sometimes facilitate this process by allowing their students to prepare a one-page crib sheet (an old-fashioned term for a "cheat sheet") crammed with information.
Students are allowed to use the crib sheet during a final exam. By the time the students have gone to the trouble of drawing up the crib sheet, they hardly need it, because the information is well organized and accessible to memory.
Bransford, J. (1979). Human Cognition: Learning, Understanding, and Remembering. Belmont, CA: Wadsworth.
Nelson, T. O. & Dunlosky, J. (1991). When people's judgments of learning (JOLs) are extremely accurate at predicting subsequent recall: The 'delayed-JOL effect'. Psychological Science, 2, 267-270.
Write to Dr. Dewey at email@example.com.
Copyright © 2007-2017 Russ Dewey