Distributed Practice in Verbal Recall Tasks: A Review and

Quantitative SynthesisBy Nicholas J. Cepeda, Harold Pashler, Edward Vul, John

Wixted, Doug Rohrer

Psychological Bulletin, 2006, Vol. 132, No. 3, 354-380

Overview

• A meta-meta study looking at how memorization pacing affects retention.

Vocabulary• Distributed Practice Effect: “An effect of interstudy interval (ISI) upon

learning, as measured on subsequent tests.”

• ISI: “The interval separating different study episodes of the same materials.”

• Spaced learning: “A measurable time lag (1 s or longer) separates study episodes.”

• Massed learning: “[P]articipant sees a single presentation of the item for twice the presentation time of a comparable spaced item.”

• Spacing Effect: “Enhanced learning during spaced as compared with massed study episodes”

• Lag Effect: “Comparisons of different levels of spacing” (Items or time)(pg. 354)

Primary Meta-Studies

Articles ThrustConclusions

Moss

1996120

Divided studies by age and type of material (verbal, motor or intellectual)

Longer ISIs facilitate learning in 80% of verbal and motor skills, but only help in 1/3 of cases involving intellectual skills (math)

Lee & Genovese

198847 Motor skills only

Distributed Practice improves both acquisition and retention. This overturns a previous (1987) study by Adams.

Donovan & Radosevich

199963

Parsed studies by Domain

1. Mental requirements,,

Overall complexity, and

Methodological Rigor

2. ISI intervals:

ISI<1min, 1min<ISI<10min,

10min<ISI<1hr,

ISI>1day

3. Retention interval

1. Biggest effects for low rigor, low complexity tasks.

2. Increasing ISI = larger effect for free recall, foreign language and verbal discrimination UP TO A POINT. Then there was loss.

3. Increasing practice intervals lowers gains and retention in skill tasks (piano, typing, etc)

4. Verbal memory increased as intervals increased less than an hour, but decreased when the interval was greater than a day.

Janiszewski

200397

Verbal Memory Skills

See next page for conclusions

Previous Meta Studies Involving Distributed Practice

Janiszewski, 2003

97 articles examining Distributed Practice Effects in verbal memory tasks

Stimuli which had zero effect:1. Verbal vs. Picture

2. Novel vs. Familiar

3. Unimodal vs. Bimodal

4. Structural vs. Semantic Cues

5. Isolated vs. Embedded Cues

ISI Factors that did affect learning and retention:

1. Lag time: the longer the ISI, the greater the effect.

2. Stimulus meaningfulness: the more meaningful the stimulous, the great the gain.

3. Semantic complexity: the more complex, the greater gain as opposed to both structurally complex and semantically simple.

4. Intentional learning was more greatly affected than incidental learning

5. Intervening material that was semantically complex yielded higher effect sizes that using intervening material that was either semantically simple or structurally complex.:

Meta Studies Involving Distributed Practice

Criticisms of Previous Studies

• Some conflicting conclusions

• Need to study joint effects of ISI, retention interval and task.

• Open question on the effect of confounding of learning/relearning in studies with more than one memorization session.

Cepeda,Pashler, Vul, Wixted and Rohrer Meta-Study (CPVWR)

• Verbal memory tasks only

• Two or more learning opportunities per item

• Studies included some with children and adults

• Clinical populations excluded

• 317 experiments from 184 articles

Bottom Line Results from CPVWR

From http://psy2.ucsd.edu/~jwixted/Reprints/Cepeda%20et%20al.%20%282006%29.pdf, July 5th, 2010

Take Home

• Separating learning sessions by at least one day maximizes long-term retention.

• Learning is best retained when the sessions are spread over weeks or months.

• No optimum interval identified as of this article’s publication.

• “Don’t try to live your life in one day. Don’t go speed your time away.” --Howard Jones

Questions/Criticisms

• Why did CPVWR include data with such enormously high p-values? (See previous slide.) It makes me question the value of their other tables where p-values are not explicitly stated.

• Why did the original authors publish data with such enormously high p-values?