The Critical Role of Retrieval in The Critical Role of Retrieval in LongLong--term Retentionterm Retention

Roddy RoedigerRoddy RoedigerDoug Nelson FestschriftDoug Nelson FestschriftDoug Nelson FestschriftDoug Nelson Festschrift

March 2008March 2008Photo by Jason C. K. Chan

In the contemporary study of memory, the huge majority of studies use single trial proceduresmajority of studies use single‐trial procedures.

Study material Take testSTST

From 1885 through the 1960s, most studies of learning and memory were multitrial in naturelearning and memory were multitrial in nature

Study – Test – Study – Test – Study – TestStudy Test   Study Test   Study  TestST ST ST

This latter procedure produces an exponentialThis latter procedure produces an exponential learning curve.

The question of central interest over the years is:The question of central interest over the years is:Why do learning curves go up?

Tulving (1962)

Continuity versus non‐continuity in learning Or incremental versus all‐or‐none learningOr incremental versus all or none learning 

theories

Many theories of learningMany theories of learning

At the most general level: Some process d i h i t d hoccurs during each successive study phase

that is expressed on the following test

S T S T S T S T S T S T S T S T S T. . .S T S T S T S T S T S T S T S T S T. . .

LearningLearningLearningLearning

Karpicke & Roediger (JML, 2007)

• Conceptual replication of Tulving (1967)

• Longer times for study and test• Longer times for study and test

• Used the Tulving & Colotla (1970) method to estimate contribution of primary memory and then removed PM from the data

• 40 unrelated words 2‐min S and T periods40 unrelated words, 2 min S and T periods

• 5 cycles (20 2‐min periods)

• STST 10 study, 10 test

• SSST 15 study 5 testSSST 15 study,   5 test

• STTT 5 study, 15 test

Final free recall test 1 week after learning

Learning Phase

90

1.00

.70

.80

.90

.40

.50

.60

10

.20

.30 Standard (STST)

Repeated Study (SSST)

Repeated Test (STTT).00

.10

0 4 8 12 16 20

T i l

Repeated Test (STTT)

Trials

Karpicke & Roediger (2007)

5 S / 15 T   >   15 S / 5 T

.68.70

.64.65

.57

.60

.55

.50STST STTT SSST

L i C ditiLearning Condition

Karpicke & Roediger (2007)

Experiment 2

Four conditions:Four conditions:Standard:  STST…Revised: SSTT…Revised: SSTT…Dropout‐Study: STSNT…Dropout‐Study and Test: STSNTN…p y N N 

• Note: Last condition is analogous to the often‐grecommended condition for studying with flashcards

Karpicke & Roediger (2007)

Cumulative recall during learning

Karpicke & Roediger (2007)

Final recall 1 week later

Karpicke & Roediger (2007)

• Alternating study/test is better than same number of study and test trials massed togethery g

• Repeated retrieval is much more important than repeated studyingrepeated studying

• Standard advice about study strategies and study‐time allocation may be wrong

• However in the previous experiment we wereHowever, in the previous experiment we were missing a needed condition

TestTest

Study

TestNon-Rcl

TestAll

STSTNSTSTStudy

All

STSNTNSTSNTStudy

Non-Rcl

Karpicke & Roediger (Science, 2008)Karpicke & Roediger (Science, 2008)

• Paired‐associate learningPaired associate learning

• 40 Swahili‐English word pairs

Study: mashua – boatStudy:  mashua  boat

Test:  mashua – ???

• Use all 4 conditions• Use all 4 conditionsStudy all, test all STST

Study all, test nonrecalled STSTNStudy all, test nonrecalled STSTNStudy nonrecalled, test all STSNT

Study nonrecalled, test nonrecalled STSNTNN N

Learning Phase

Karpicke & Roediger (2008)

Metamemory: Subjective Experience

Aggregate Judgment of LearningAggregate Judgment of Learning

“How many words will you recall in 1 week?”

All conditions = ~ 50% (no diffs)( )

Karpicke & Roediger (2008)

Final recall 1 week later

Karpicke & Roediger (2008)

Conclusions

• Repeated retrieval is the key to long‐termRepeated retrieval is the key to long term retention

• Beyond some minimal amount repeated• Beyond some minimal amount, repeated studying does not matter

“Exercise in repeatedly recalling a thing strengthens the memory”strengthens the memory--Aristotle, De Memoria et Reminiscentia

This research is supported by grants from the James S. McDonnell Foundation and the Institute of Educational  Sciences to Roddy Roediger, Kathleen McDermott, and Mark gMcDaniel.