Temporal Spacing of Learning: Can It Help Reduce Forgetting? Hal Pashler University of California, San Diego Dept of Psychology

Douglas Rohrer, USF John Wixted, UCSD Nicholas Cepeda, UCSD & Univ of Colorado Shana Carpenter, UCSD

Michael Mozer, Univ of Colorado Computer Science Dept. Ed Vul, MIT

Forgetting: A Classic Topic in Experimental Psychology

Forgetting in K-12 Education Educational failure may often reflect forgetting as well as absence of initial mastery. Summer Vacation Set-backs “Regression” to partial understanding and initial misunderstandings (Bob Siegler).

“People who went to college can tell you what they learned in just 5 minutes. So, at my college, students learn just the same stuff – all in 5 minutes.” Father Guido Sarducci’s 5-Minute College

Our Research Aim: Identify procedures that can readily be applied in educational contexts. reduce rate of forgetting

2. Temporal Distribution of Study Sessions 4. Form and Timing of Feedback 1. Temporal Distribution of Practice within Study Sessions 3. Overlearning Topics 5. Testing Effects

Analyzing Temporal Distribution of Study Sessions Time Study Something Once Study It Again Test Inter-study Interval (ISI) Retention Interval (RI) Scarcely any application in classroom or instructional technology Huge Literature showing poor learning with very short ISI (“spacing effect”)

Why no practical translation if the literature is so huge? 425 papers

Spacing Research with Significant Retention Intervals (> 1 day) 14 papers (Many with serious methodological problems)

10-day Retention Interval Study Jani?Horse Interstudy Interval = 0, 1, 2, 4, 7, 14 days Tasks Swahili-English Vocabulary Session 1: Study to Criterion [0,1,2,4,7, or 14 days] Session 2: Fixed amount of further study [10 day RI] Session 3: Test

Facts Objects 10-day RI Data from 182 subjects tested for 3 sessions

6-Month Retention Interval ? Coccolith. Interstudy Interval = 0, 1, 7, 28, 84, or 168 days Tasks 1. Learn names of little-known objects 2. Learn little-known facts Who invented snow golf?Rudyard Kipling.

6-month RI: Facts Swahili10-day RI 6-month RI: Object Names Data from 161 subjects tested for 3 sessions

Optimum ISI = 10 – 20% of retention interval? Let’s Plot Performance as a Function of ISI/RI Ratio

Larger Experiment now in Progress RI = {7, 35, 70, or 350 days} ISI = {0, 7, 14, 21, or 105 days} X Web-based Learning of Facts Session 1: Train to Criterion Session 2: 2 Test/Study Repetitions Test: Recall, then 5-Alternative Recognition

Recall Data (n ~ 2,000 subjects) 7 days RI 35 days RI 70 days RI 350 days RI

Recognition Data (n ~ 2,000 subjects) 7 days RI 35 days RI 70 days RI 350 days RI

Large effects of spacing generalize to learning novel mathematical problem-solving skill (combinatorics) [USF] Generalizing Beyond Fact & Vocabulary Learning Pattern-recognition skills may not show similar spacing effects [

Empirical Conclusions Using ISI of about 10-20% of retention interval seem to optimize memory over a wide time range Too short an ISI is much worse than too long Using appropriate inter-study interval can produce 100% - 200% improvement in ultimate memory

To determine optimum spacing, you need to know how long you want the learner to retain the information. For most educational goals, 6-mo. delayed reviews likely to be very cost-effective (Preuss School Study) Cumulative finals probably have huge effect on what students retain over years. Tentative Practical Implications