Interference with other tasks in practice helps long-term retention of skills: implications for classroom teaching and training in many professions and sports
WASHINGTON - To learn a skill well enough to excel in a job or sport, practice must be structured in certain ways to ensure long-term retention.
A new study confirms earlier research on both verbal and motor learning that practicing several different skills in separate, concentrated blocks leads to better performance during practice but not during the actual task.
For long-term retention, say researchers, contextual-interference practice (practicing skills that are mixed with other tasks) results in better learning than does blocked practice. These results are reported on in the current issue of Journal of Experimental Psychology: Learning, Memory and Cognition.
A temporary boost that blocked practice provides allows people to overestimate how well they have learned the skills they practiced, according to study authors Dominic A. Simon, Ph.D., of McMaster University in Hamilton, Ontario and Robert A. Bjork, Ph.D., of the University of California in Los Angeles, California. "People are often poor assessors of what they have learned. They often base their expectations of future performance on their performance now," said lead author Simon.
The assumption that a person is prepared to do something but really isn't could have devastating consequences, said the authors. "If the person is a surgeon and is tying off a suture during surgery and hasn't mastered the skill, the outcome could be tragic."
The fact that blocked practice leads to better short-term performance but poorer long-term learning "has great potential to fool teachers, trainers and instructors as well as students and trainees themselves," adds Dr. Bjork. "It's natural to think that progress means we are learning and struggling and making mistakes means we are not learning as well. Those who train others may lean toward training conditions that are far from helping someone really retain what they are learning."
To find out how people's learning fits with their sense of how well they have learned - "their metacognition" - the authors assigned 48 participants to practice typing three different five-key sequences on the number pad of a computer keyboard. The participants were asked to complete each of the three sequences as closely as possible to a specified goal movement time, which was different for each sequence.
Half the participants were assigned to a "blocked practice" condition, in which they practiced the three key sequences, each in a separate block until they correctly completed each sequence 30 times. The remaining participants were assigned to a "random practice" condition, in which the three patterns were randomly interleaved. In both conditions, participants received feedback about their performance accuracy and speed after each trial.
During the practice, the participants were asked to indicate how well they thought they had learned the key sequences by predicting how well they would perform the same sequences on a retention test the next day. They took a pencil and paper test the next day, which measured how well they remembered the three keystroke sequences and their associated goal movement times. Then, they predicted how well they would perform on each of the patterns. Finally, the participants took a retention test, performing each of the key sequences six times - half in a blocked condition and half in a random condition.
Participants in the blocked practice condition performed better than did those in the random practice condition, especially early in the practice session. And as the authors expected, those participants in the blocked practice condition expected to perform better on the retention test than the participants in the random practice condition. The opposite happened.
"Those in the blocked condition performed substantially worse than did those in the random condition on both the paper and pencil test of their recall of the motor sequences and the timed performance test," said the authors. "But those in the random condition were quite accurate in predicting how well they would retain what they had learned."
Why blocked practices only lead to short-term gains and random practices were better at long-term learning may be because random practice required people to repeatedly "reload" the motor program corresponding to each task, which aids the later retrieval of that program, explain the authors. Another explanation for random practice being superior to long-term learning than block practice is that it requires that several skills be differentiated in terms of their similarities and differences resulting in a better mental conceptualization that supports retention of those skills.
"Blocked practice encourages people to make trial-by-trial adjustments, which enhance current performance," said Dr. Bjork, "but do not induce retrieval processes and conceptual categorization of the types that enhance learning. The problem is that if people confuse the current sense of ease with learning, they'll prefer training conditions over real-life conditions."
Article: "Metacognition in Motor Learning," Dominic A. Simon, Ph.D., McMaster University and Robert A. Bjork, Ph.D., University of California, Los Angeles; Journal of Experimental Psychology: Learning, Memory and Cognition, 2001, Vol. 27, No. 4.
Full text of the article is available from the APA Public Affairs Office. Dominic A. Simon can be reached by phone at 905-525-9140 or by email at email@example.com
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