The DOI matches its Crossref record; 30 of the 32 references it cites were found in a registry or an index; 3 of the 24 sources its claims cite were checked for support.
Spacing Effects in Learning: A Temporal Ridgeline of Optimal Retention
Open accessAbstract
To achieve enduring retention, people must usually study information on multiple occasions. How does the timing of study events affect retention? Prior research has examined this issue only in a spotty fashion, usually with very short time intervals. In a study aimed at characterizing spacing effects over significant durations, more than 1,350 individuals were taught a set of facts and--after a gap of up to 3.5 months--given a review. A final test was administered at a further delay of up to 1 year. At any given test delay, an increase in the interstudy gap at first increased, and then gradually reduced, final test performance. The optimal gap increased as test delay increased. However, when measured as a proportion of test delay, the optimal gap declined from about 20 to 40% of a 1-week test delay to about 5 to 10% of a 1-year test delay. The interaction of gap and test delay implies that many educational practices are highly inefficient.
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19 Own result · 8 Own interpretation · 5 No full text of the sources · 5 Own method · 3 Sources not found · 2 Partly supported · 2 Not checked yet · 2 No basis given · 1 Supported so far · accuracy not yet measured
The sources with a verdict support this claim; the rest weren’t checked yet, have no full text we could read, or their verdicts aren’t rated yet.
In the paper
“Several studies involving modest time intervals ranging from minutes to days have found that memory at the final test is best for intermediate gap durations (e.g., Balota, Duchek, & Paullin, 1989;Glenberg, 1976;Glenberg & Lehmann, 1980;Young, 1966; see Cepeda et al., 2006, for a meta-analysis focused on this point).”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Spacing Effects in Learning: A Temporal Ridgeline of Optimal Retention
What the sources say
- Not matchedcites Balota, Duchek, & Paullin, 1989
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- Not checked — no full text of the sourcecites Glenberg, 1976 source
- Supportedcites Cepeda et al., 2006 source
The General Discussion (p. 11) reports that, for a given retention interval, an intermediate, non-zero inter-study interval maximized final-test accuracy: longer gaps eventually reduced it. The within-study analysis (p. 9) identifies several studies with results consistent with this pattern, including Balota et al., Glenberg, and Glenberg and Lehmann. (LLM, conf=0.93)
plaincorrelational- Asserted: passes — The authors put it forward as true.
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- Not matched
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In the paper
“Other distributed practice theories, such as encoding variability (Glenberg, 1979) and study-phase retrieval (Murray, 1983) are potentially consistent with the basic results seen in Figure 3.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Theoretical Implications
What the sources say
- Supportedcites Glenberg, 1979 source
Glenberg’s introduction (p. 1) describes his account of spacing effects in terms of variable encoding, and the General Discussion (p. 15) says an encoding-variability theory could account for several spacing phenomena. The citation identifies the theory; whether it fits the citing paper’s Figure 3 is the citing authors’ own qualified assessment. (LLM, conf=0.90)
- Not matchedcites Murray, 1983
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
hedged- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Supported
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For a fixed amount of study time, the optimal gap provided a 64% increase, d = 1.1, in final recall, and a 26% increase, d = 1.5, in final recognition, as compared to a zero-day gap”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Results Figure 3 shows the effect of gap on recall and recognition for each of the four different retention intervals, for the subjects who completed all the phases of the study.For each retention interval, final performance always rose initially with increasing gap and then fell as gap was further increased.The effects of gap were very large in magnitude: For a fixed amount of study time, the optimal gap provided a 64% increase, d = 1.1, in final recall, and a 26% increase, d = 1.5, in final recognition, as compared to a zero-day gap (in the present article, d values refer to the comparison of zeroday versus optimal gap).For the RIs of 7, 35, 70, and 350 days, the optimal gaps (of those included in the study) were 1, 11, 21, and 21 days, respectively, for recall data, and 1, 7, 7, and 21 days, respectively, for recognition data.All of these findings are in good agreement with the lab benchmark dataset, which, with its RI of 6 months, lay about where it would be expected to between the RI = 70 and RI = 350 conditionsdespite the fact that the laboratory study fixed session 2 exposure duration and the current study did not.(Both studies provided a fixed number of relearning trials.)For 7, 35, 70, and 350 day RIs, percentage improvements in recall for optimal versus zeroday gaps were 10, 59, 111, and 77%-t(124) = 6.5, p rep = .99,d = 1.3; t(111) = 8.9, p rep = .99,d = 0.6; t(102) = 8.6, p rep = .99,d = 1.7; t(68) = 3.9, p rep = .99,d = 0.9, respectively.For recognition data, percentage improvements for optimal versus zero-day gaps were 1, 10, 31, and 60%-t(124) = 2.3, p rep = .99,d = 0.7; t(136) = 7.5, p rep = .99,d = In Press, Psychological Science Spacing Effects in Learning 5 1.5; t(112) = 8.7, p rep = .99,d = 1.7; t(68) = 7.9, p rep = .99,d = 2.1 for 7, 35, 70, and 350 day RIs, respectively.Estimated optimal gap values rise as retention interval is increased, and these depart noticeably from the fixed ratio of retention interval suggested by some earlier researchers based on much shorter-term studies (Crowder, 1976;Murray, 1983).
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For 7, 35, 70, and 350 day RIs, percentage improvements in recall for optimal versus zeroday gaps were 10, 59, 111, and 77%-t(124) = 6.5, p rep = .99,d = 1.3; t(111) = 8.9, p rep = .99,d = 0.6; t(102) = 8.6, p rep = .99,d = 1.7; t(68) = 3.9, p rep = .99,d = 0.9, respectively.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Results Figure 3 shows the effect of gap on recall and recognition for each of the four different retention intervals, for the subjects who completed all the phases of the study.For each retention interval, final performance always rose initially with increasing gap and then fell as gap was further increased.The effects of gap were very large in magnitude: For a fixed amount of study time, the optimal gap provided a 64% increase, d = 1.1, in final recall, and a 26% increase, d = 1.5, in final recognition, as compared to a zero-day gap (in the present article, d values refer to the comparison of zeroday versus optimal gap).For the RIs of 7, 35, 70, and 350 days, the optimal gaps (of those included in the study) were 1, 11, 21, and 21 days, respectively, for recall data, and 1, 7, 7, and 21 days, respectively, for recognition data.All of these findings are in good agreement with the lab benchmark dataset, which, with its RI of 6 months, lay about where it would be expected to between the RI = 70 and RI = 350 conditionsdespite the fact that the laboratory study fixed session 2 exposure duration and the current study did not.(Both studies provided a fixed number of relearning trials.)For 7, 35, 70, and 350 day RIs, percentage improvements in recall for optimal versus zeroday gaps were 10, 59, 111, and 77%-t(124) = 6.5, p rep = .99,d = 1.3; t(111) = 8.9, p rep = .99,d = 0.6; t(102) = 8.6, p rep = .99,d = 1.7; t(68) = 3.9, p rep = .99,d = 0.9, respectively.For recognition data, percentage improvements for optimal versus zero-day gaps were 1, 10, 31, and 60%-t(124) = 2.3, p rep = .99,d = 0.7; t(136) = 7.5, p rep = .99,d = In Press, Psychological Science Spacing Effects in Learning 5 1.5; t(112) = 8.7, p rep = .99,d = 1.7; t(68) = 7.9, p rep = .99,d = 2.1 for 7, 35, 70, and 350 day RIs, respectively.Estimated optimal gap values rise as retention interval is increased, and these depart noticeably from the fixed ratio of retention interval suggested by some earlier researchers based on much shorter-term studies (Crowder, 1976;Murray, 1983).
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“At any given retention interval, an increase in the inter-study gap at first increased, and then gradually reduced, test performance.”
- Also stated in: § Results Figure 3 shows the effect of gap on recall and recognition for each of the four different retention intervals, for the subjects who completed all the phases of the study.For each retention interval, final performance always rose initially with increasing gap and then fell as gap was further increased.The effects of gap were very large in magnitude: For a fixed amount of study time, the optimal gap provided a 64% increase, d = 1.1, in final recall, and a 26% increase, d = 1.5, in final recognition, as compared to a zero-day gap (in the present article, d values refer to the comparison of zeroday versus optimal gap).For the RIs of 7, 35, 70, and 350 days, the optimal gaps (of those included in the study) were 1, 11, 21, and 21 days, respectively, for recall data, and 1, 7, 7, and 21 days, respectively, for recognition data.All of these findings are in good agreement with the lab benchmark dataset, which, with its RI of 6 months, lay about where it would be expected to between the RI = 70 and RI = 350 conditionsdespite the fact that the laboratory study fixed session 2 exposure duration and the current study did not.(Both studies provided a fixed number of relearning trials.)For 7, 35, 70, and 350 day RIs, percentage improvements in recall for optimal versus zeroday gaps were 10, 59, 111, and 77%-t(124) = 6.5, p rep = .99,d = 1.3; t(111) = 8.9, p rep = .99,d = 0.6; t(102) = 8.6, p rep = .99,d = 1.7; t(68) = 3.9, p rep = .99,d = 0.9, respectively.For recognition data, percentage improvements for optimal versus zero-day gaps were 1, 10, 31, and 60%-t(124) = 2.3, p rep = .99,d = 0.7; t(136) = 7.5, p rep = .99,d = In Press, Psychological Science Spacing Effects in Learning 5 1.5; t(112) = 8.7, p rep = .99,d = 1.7; t(68) = 7.9, p rep = .99,d = 2.1 for 7, 35, 70, and 350 day RIs, respectively.Estimated optimal gap values rise as retention interval is increased, and these depart noticeably from the fixed ratio of retention interval suggested by some earlier researchers based on much shorter-term studies (Crowder, 1976;Murray, 1983). · boosted
“For each retention interval, final performance always rose initially with increasing gap and then fell as gap was further increased.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Abstract
boosteddirectn = 1,350- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Also stated in: § Results Figure 3 shows the effect of gap on recall and recognition for each of the four different retention intervals, for the subjects who completed all the phases of the study.For each retention interval, final performance always rose initially with increasing gap and then fell as gap was further increased.The effects of gap were very large in magnitude: For a fixed amount of study time, the optimal gap provided a 64% increase, d = 1.1, in final recall, and a 26% increase, d = 1.5, in final recognition, as compared to a zero-day gap (in the present article, d values refer to the comparison of zeroday versus optimal gap).For the RIs of 7, 35, 70, and 350 days, the optimal gaps (of those included in the study) were 1, 11, 21, and 21 days, respectively, for recall data, and 1, 7, 7, and 21 days, respectively, for recognition data.All of these findings are in good agreement with the lab benchmark dataset, which, with its RI of 6 months, lay about where it would be expected to between the RI = 70 and RI = 350 conditionsdespite the fact that the laboratory study fixed session 2 exposure duration and the current study did not.(Both studies provided a fixed number of relearning trials.)For 7, 35, 70, and 350 day RIs, percentage improvements in recall for optimal versus zeroday gaps were 10, 59, 111, and 77%-t(124) = 6.5, p rep = .99,d = 1.3; t(111) = 8.9, p rep = .99,d = 0.6; t(102) = 8.6, p rep = .99,d = 1.7; t(68) = 3.9, p rep = .99,d = 0.9, respectively.For recognition data, percentage improvements for optimal versus zero-day gaps were 1, 10, 31, and 60%-t(124) = 2.3, p rep = .99,d = 0.7; t(136) = 7.5, p rep = .99,d = In Press, Psychological Science Spacing Effects in Learning 5 1.5; t(112) = 8.7, p rep = .99,d = 1.7; t(68) = 7.9, p rep = .99,d = 2.1 for 7, 35, 70, and 350 day RIs, respectively.Estimated optimal gap values rise as retention interval is increased, and these depart noticeably from the fixed ratio of retention interval suggested by some earlier researchers based on much shorter-term studies (Crowder, 1976;Murray, 1983). · boosted
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For recognition data, percentage improvements for optimal versus zero-day gaps were 1, 10, 31, and 60%-t(124) = 2.3, p rep = .99,d = 0.7; t(136) = 7.5, p rep = .99,d = In Press, Psychological Science Spacing Effects in Learning 5 1.5; t(112) = 8.7, p rep = .99,d = 1.7; t(68) = 7.9, p rep = .99,d = 2.1 for 7, 35, 70, and 350 day RIs, respectively.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Results Figure 3 shows the effect of gap on recall and recognition for each of the four different retention intervals, for the subjects who completed all the phases of the study.For each retention interval, final performance always rose initially with increasing gap and then fell as gap was further increased.The effects of gap were very large in magnitude: For a fixed amount of study time, the optimal gap provided a 64% increase, d = 1.1, in final recall, and a 26% increase, d = 1.5, in final recognition, as compared to a zero-day gap (in the present article, d values refer to the comparison of zeroday versus optimal gap).For the RIs of 7, 35, 70, and 350 days, the optimal gaps (of those included in the study) were 1, 11, 21, and 21 days, respectively, for recall data, and 1, 7, 7, and 21 days, respectively, for recognition data.All of these findings are in good agreement with the lab benchmark dataset, which, with its RI of 6 months, lay about where it would be expected to between the RI = 70 and RI = 350 conditionsdespite the fact that the laboratory study fixed session 2 exposure duration and the current study did not.(Both studies provided a fixed number of relearning trials.)For 7, 35, 70, and 350 day RIs, percentage improvements in recall for optimal versus zeroday gaps were 10, 59, 111, and 77%-t(124) = 6.5, p rep = .99,d = 1.3; t(111) = 8.9, p rep = .99,d = 0.6; t(102) = 8.6, p rep = .99,d = 1.7; t(68) = 3.9, p rep = .99,d = 0.9, respectively.For recognition data, percentage improvements for optimal versus zero-day gaps were 1, 10, 31, and 60%-t(124) = 2.3, p rep = .99,d = 0.7; t(136) = 7.5, p rep = .99,d = In Press, Psychological Science Spacing Effects in Learning 5 1.5; t(112) = 8.7, p rep = .99,d = 1.7; t(68) = 7.9, p rep = .99,d = 2.1 for 7, 35, 70, and 350 day RIs, respectively.Estimated optimal gap values rise as retention interval is increased, and these depart noticeably from the fixed ratio of retention interval suggested by some earlier researchers based on much shorter-term studies (Crowder, 1976;Murray, 1983).
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For the RIs of 7, 35, 70, and 350 days, the optimal gaps (of those included in the study) were 1, 11, 21, and 21 days, respectively, for recall data, and 1, 7, 7, and 21 days, respectively, for recognition data.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Results Figure 3 shows the effect of gap on recall and recognition for each of the four different retention intervals, for the subjects who completed all the phases of the study.For each retention interval, final performance always rose initially with increasing gap and then fell as gap was further increased.The effects of gap were very large in magnitude: For a fixed amount of study time, the optimal gap provided a 64% increase, d = 1.1, in final recall, and a 26% increase, d = 1.5, in final recognition, as compared to a zero-day gap (in the present article, d values refer to the comparison of zeroday versus optimal gap).For the RIs of 7, 35, 70, and 350 days, the optimal gaps (of those included in the study) were 1, 11, 21, and 21 days, respectively, for recall data, and 1, 7, 7, and 21 days, respectively, for recognition data.All of these findings are in good agreement with the lab benchmark dataset, which, with its RI of 6 months, lay about where it would be expected to between the RI = 70 and RI = 350 conditionsdespite the fact that the laboratory study fixed session 2 exposure duration and the current study did not.(Both studies provided a fixed number of relearning trials.)For 7, 35, 70, and 350 day RIs, percentage improvements in recall for optimal versus zeroday gaps were 10, 59, 111, and 77%-t(124) = 6.5, p rep = .99,d = 1.3; t(111) = 8.9, p rep = .99,d = 0.6; t(102) = 8.6, p rep = .99,d = 1.7; t(68) = 3.9, p rep = .99,d = 0.9, respectively.For recognition data, percentage improvements for optimal versus zero-day gaps were 1, 10, 31, and 60%-t(124) = 2.3, p rep = .99,d = 0.7; t(136) = 7.5, p rep = .99,d = In Press, Psychological Science Spacing Effects in Learning 5 1.5; t(112) = 8.7, p rep = .99,d = 1.7; t(68) = 7.9, p rep = .99,d = 2.1 for 7, 35, 70, and 350 day RIs, respectively.Estimated optimal gap values rise as retention interval is increased, and these depart noticeably from the fixed ratio of retention interval suggested by some earlier researchers based on much shorter-term studies (Crowder, 1976;Murray, 1983).
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For the RIs of 7, 35, 70, and 350 days, the optimal gaps (of those included in the study) were 1, 11, 21, and 21 days, respectively, for recall data, and 1, 7, 7, and 21 days, respectively, for recognition data.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Results Figure 3 shows the effect of gap on recall and recognition for each of the four different retention intervals, for the subjects who completed all the phases of the study.For each retention interval, final performance always rose initially with increasing gap and then fell as gap was further increased.The effects of gap were very large in magnitude: For a fixed amount of study time, the optimal gap provided a 64% increase, d = 1.1, in final recall, and a 26% increase, d = 1.5, in final recognition, as compared to a zero-day gap (in the present article, d values refer to the comparison of zeroday versus optimal gap).For the RIs of 7, 35, 70, and 350 days, the optimal gaps (of those included in the study) were 1, 11, 21, and 21 days, respectively, for recall data, and 1, 7, 7, and 21 days, respectively, for recognition data.All of these findings are in good agreement with the lab benchmark dataset, which, with its RI of 6 months, lay about where it would be expected to between the RI = 70 and RI = 350 conditionsdespite the fact that the laboratory study fixed session 2 exposure duration and the current study did not.(Both studies provided a fixed number of relearning trials.)For 7, 35, 70, and 350 day RIs, percentage improvements in recall for optimal versus zeroday gaps were 10, 59, 111, and 77%-t(124) = 6.5, p rep = .99,d = 1.3; t(111) = 8.9, p rep = .99,d = 0.6; t(102) = 8.6, p rep = .99,d = 1.7; t(68) = 3.9, p rep = .99,d = 0.9, respectively.For recognition data, percentage improvements for optimal versus zero-day gaps were 1, 10, 31, and 60%-t(124) = 2.3, p rep = .99,d = 0.7; t(136) = 7.5, p rep = .99,d = In Press, Psychological Science Spacing Effects in Learning 5 1.5; t(112) = 8.7, p rep = .99,d = 1.7; t(68) = 7.9, p rep = .99,d = 2.1 for 7, 35, 70, and 350 day RIs, respectively.Estimated optimal gap values rise as retention interval is increased, and these depart noticeably from the fixed ratio of retention interval suggested by some earlier researchers based on much shorter-term studies (Crowder, 1976;Murray, 1983).
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For a fixed amount of study time, the optimal gap provided a 64% increase, d = 1.1, in final recall, and a 26% increase, d = 1.5, in final recognition, as compared to a zero-day gap”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Results Figure 3 shows the effect of gap on recall and recognition for each of the four different retention intervals, for the subjects who completed all the phases of the study.For each retention interval, final performance always rose initially with increasing gap and then fell as gap was further increased.The effects of gap were very large in magnitude: For a fixed amount of study time, the optimal gap provided a 64% increase, d = 1.1, in final recall, and a 26% increase, d = 1.5, in final recognition, as compared to a zero-day gap (in the present article, d values refer to the comparison of zeroday versus optimal gap).For the RIs of 7, 35, 70, and 350 days, the optimal gaps (of those included in the study) were 1, 11, 21, and 21 days, respectively, for recall data, and 1, 7, 7, and 21 days, respectively, for recognition data.All of these findings are in good agreement with the lab benchmark dataset, which, with its RI of 6 months, lay about where it would be expected to between the RI = 70 and RI = 350 conditionsdespite the fact that the laboratory study fixed session 2 exposure duration and the current study did not.(Both studies provided a fixed number of relearning trials.)For 7, 35, 70, and 350 day RIs, percentage improvements in recall for optimal versus zeroday gaps were 10, 59, 111, and 77%-t(124) = 6.5, p rep = .99,d = 1.3; t(111) = 8.9, p rep = .99,d = 0.6; t(102) = 8.6, p rep = .99,d = 1.7; t(68) = 3.9, p rep = .99,d = 0.9, respectively.For recognition data, percentage improvements for optimal versus zero-day gaps were 1, 10, 31, and 60%-t(124) = 2.3, p rep = .99,d = 0.7; t(136) = 7.5, p rep = .99,d = In Press, Psychological Science Spacing Effects in Learning 5 1.5; t(112) = 8.7, p rep = .99,d = 1.7; t(68) = 7.9, p rep = .99,d = 2.1 for 7, 35, 70, and 350 day RIs, respectively.Estimated optimal gap values rise as retention interval is increased, and these depart noticeably from the fixed ratio of retention interval suggested by some earlier researchers based on much shorter-term studies (Crowder, 1976;Murray, 1983).
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Estimated optimal gap values rise as retention interval is increased”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Results Figure 3 shows the effect of gap on recall and recognition for each of the four different retention intervals, for the subjects who completed all the phases of the study.For each retention interval, final performance always rose initially with increasing gap and then fell as gap was further increased.The effects of gap were very large in magnitude: For a fixed amount of study time, the optimal gap provided a 64% increase, d = 1.1, in final recall, and a 26% increase, d = 1.5, in final recognition, as compared to a zero-day gap (in the present article, d values refer to the comparison of zeroday versus optimal gap).For the RIs of 7, 35, 70, and 350 days, the optimal gaps (of those included in the study) were 1, 11, 21, and 21 days, respectively, for recall data, and 1, 7, 7, and 21 days, respectively, for recognition data.All of these findings are in good agreement with the lab benchmark dataset, which, with its RI of 6 months, lay about where it would be expected to between the RI = 70 and RI = 350 conditionsdespite the fact that the laboratory study fixed session 2 exposure duration and the current study did not.(Both studies provided a fixed number of relearning trials.)For 7, 35, 70, and 350 day RIs, percentage improvements in recall for optimal versus zeroday gaps were 10, 59, 111, and 77%-t(124) = 6.5, p rep = .99,d = 1.3; t(111) = 8.9, p rep = .99,d = 0.6; t(102) = 8.6, p rep = .99,d = 1.7; t(68) = 3.9, p rep = .99,d = 0.9, respectively.For recognition data, percentage improvements for optimal versus zero-day gaps were 1, 10, 31, and 60%-t(124) = 2.3, p rep = .99,d = 0.7; t(136) = 7.5, p rep = .99,d = In Press, Psychological Science Spacing Effects in Learning 5 1.5; t(112) = 8.7, p rep = .99,d = 1.7; t(68) = 7.9, p rep = .99,d = 2.1 for 7, 35, 70, and 350 day RIs, respectively.Estimated optimal gap values rise as retention interval is increased, and these depart noticeably from the fixed ratio of retention interval suggested by some earlier researchers based on much shorter-term studies (Crowder, 1976;Murray, 1983).
hedgeddirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Third, as RI increases, the optimal gap should increase (see Figure 3A), as shown by the direction of the red ridgeline in Figure 4.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Discussion
plaindirect- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The present results show that the timing of learning sessions can have powerful effects on retention with study time equated”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Educational Implications
plaindirect- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“while there are costs to using a gap that is longer than the optimal value, these costs are much smaller than the costs of using too small a gap value, as evidenced by the fact that, as gap increases, accuracy increases steeply and then declines much more gradually (Figure 3).”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Educational Implications
plaindirect- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Second, for any RI greater than zero, an increase in study gap should cause recall to first increase and then decrease.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Discussion
hedgeddirect- Asserted: passes — The authors put it forward as true.
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In the paper
“Fourth, as RI increases, the ratio of optimal gap to RI must decline.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Discussion
plaindirect- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We have conducted our own simulations of Pavlik and Anderson's ACT-R model and Raaijmaker's SAM model, in order to determine if these models can characterize the ridgeline of optimal retention.We were not able to fit both the increase in optimal gap as a function of RI and the decrease in gap/RI ratio as a function of increasing RI.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Theoretical Implications
plain- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The proportion of subjects whose performance might be termed”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Appendix: Comments and Validity of Internet Memory Testing Data
hedged- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For example, comparing gap and RI values that were roughly the same in both the current study and the benchmark study, average performance on the final test was 41% in the current study and 45% for the benchmark study.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Appendix: Comments and Validity of Internet Memory Testing Data
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Based on short term studies, one cannot answer with confidence even such basic questions as”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Spacing Effects in Learning 2
plain- Asserted: passes — The authors put it forward as true.
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A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“Another issue in interpreting the Bahrick studies (Bahrick et al., 1993;Bahrick & Phelps, 1987) is the use of a fixed performance criterion.Given the forgetting that takes place during the gap between study sessions, this inevitably means that many more relearning trials will be necessary during most sessions at the longest gap (as compared to the shortest).”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Spacing Effects in Learning 2
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
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None of the sources cited for this claim could be matched to a paper in Crossref, so there is nothing to check it against.
In the paper
“and these depart noticeably from the fixed ratio of retention interval suggested by some earlier researchers based on much shorter-term studies (Crowder, 1976;Murray, 1983).”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Results Figure 3 shows the effect of gap on recall and recognition for each of the four different retention intervals, for the subjects who completed all the phases of the study.For each retention interval, final performance always rose initially with increasing gap and then fell as gap was further increased.The effects of gap were very large in magnitude: For a fixed amount of study time, the optimal gap provided a 64% increase, d = 1.1, in final recall, and a 26% increase, d = 1.5, in final recognition, as compared to a zero-day gap (in the present article, d values refer to the comparison of zeroday versus optimal gap).For the RIs of 7, 35, 70, and 350 days, the optimal gaps (of those included in the study) were 1, 11, 21, and 21 days, respectively, for recall data, and 1, 7, 7, and 21 days, respectively, for recognition data.All of these findings are in good agreement with the lab benchmark dataset, which, with its RI of 6 months, lay about where it would be expected to between the RI = 70 and RI = 350 conditionsdespite the fact that the laboratory study fixed session 2 exposure duration and the current study did not.(Both studies provided a fixed number of relearning trials.)For 7, 35, 70, and 350 day RIs, percentage improvements in recall for optimal versus zeroday gaps were 10, 59, 111, and 77%-t(124) = 6.5, p rep = .99,d = 1.3; t(111) = 8.9, p rep = .99,d = 0.6; t(102) = 8.6, p rep = .99,d = 1.7; t(68) = 3.9, p rep = .99,d = 0.9, respectively.For recognition data, percentage improvements for optimal versus zero-day gaps were 1, 10, 31, and 60%-t(124) = 2.3, p rep = .99,d = 0.7; t(136) = 7.5, p rep = .99,d = In Press, Psychological Science Spacing Effects in Learning 5 1.5; t(112) = 8.7, p rep = .99,d = 1.7; t(68) = 7.9, p rep = .99,d = 2.1 for 7, 35, 70, and 350 day RIs, respectively.Estimated optimal gap values rise as retention interval is increased, and these depart noticeably from the fixed ratio of retention interval suggested by some earlier researchers based on much shorter-term studies (Crowder, 1976;Murray, 1983).
What the sources say
- Not matchedcites Crowder, 1976
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- Not matchedcites Murray, 1983
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plaincorrelational- Asserted: passes — The authors put it forward as true.
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- Not matched
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“but subjects who completed all three sessions did not show any reliable differences in their initial test performance from those who did not complete the final test.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Subjects.
plain- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The interaction of gap and test delay implies that many educational practices are likely to be highly inefficient.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Abstract
hedgeddirectn = 1,350- Asserted: passes — The authors put it forward as true.
- Checkable: unclear — It is unclear whether it could be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: The 32 obscure trivia facts and object names used in the study are representative of the kinds of information people need to learn and retain in educational settings.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“All of these findings are in good agreement with the lab benchmark dataset, which, with its RI of 6 months, lay about where it would be expected to between the RI = 70 and RI = 350 conditions”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Results Figure 3 shows the effect of gap on recall and recognition for each of the four different retention intervals, for the subjects who completed all the phases of the study.For each retention interval, final performance always rose initially with increasing gap and then fell as gap was further increased.The effects of gap were very large in magnitude: For a fixed amount of study time, the optimal gap provided a 64% increase, d = 1.1, in final recall, and a 26% increase, d = 1.5, in final recognition, as compared to a zero-day gap (in the present article, d values refer to the comparison of zeroday versus optimal gap).For the RIs of 7, 35, 70, and 350 days, the optimal gaps (of those included in the study) were 1, 11, 21, and 21 days, respectively, for recall data, and 1, 7, 7, and 21 days, respectively, for recognition data.All of these findings are in good agreement with the lab benchmark dataset, which, with its RI of 6 months, lay about where it would be expected to between the RI = 70 and RI = 350 conditionsdespite the fact that the laboratory study fixed session 2 exposure duration and the current study did not.(Both studies provided a fixed number of relearning trials.)For 7, 35, 70, and 350 day RIs, percentage improvements in recall for optimal versus zeroday gaps were 10, 59, 111, and 77%-t(124) = 6.5, p rep = .99,d = 1.3; t(111) = 8.9, p rep = .99,d = 0.6; t(102) = 8.6, p rep = .99,d = 1.7; t(68) = 3.9, p rep = .99,d = 0.9, respectively.For recognition data, percentage improvements for optimal versus zero-day gaps were 1, 10, 31, and 60%-t(124) = 2.3, p rep = .99,d = 0.7; t(136) = 7.5, p rep = .99,d = In Press, Psychological Science Spacing Effects in Learning 5 1.5; t(112) = 8.7, p rep = .99,d = 1.7; t(68) = 7.9, p rep = .99,d = 2.1 for 7, 35, 70, and 350 day RIs, respectively.Estimated optimal gap values rise as retention interval is increased, and these depart noticeably from the fixed ratio of retention interval suggested by some earlier researchers based on much shorter-term studies (Crowder, 1976;Murray, 1983).
plaincorrelational- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The optimally efficient gap between study sessions is not some absolute quantity that can be recommended, but a quantity that depends dramatically upon the retention interval”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Educational Implications
plaincorrelational- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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- Rests on an assumption: The 32 obscure trivia facts and object names used in the study are representative of the kinds of information people need to learn and retain in educational settings.
None of the sources cited for this claim could be matched to a paper in Crossref, so there is nothing to check it against.
In the paper
“Recent simulation work in our lab suggests that some recent quantitative theories (Pavlik & Anderson, 2003;Raaijmakers, 2003) may have trouble accounting for the present data”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Theoretical Implications
What the sources say
- Not matchedcites Pavlik & Anderson, 2003
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- Not matchedcites Raaijmakers, 2003
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- Not matchedcites Mozer et al., 2007
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
hedged- Asserted: passes — The authors put it forward as true.
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- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Not matched
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Based on the current results, this compression of learning into a too-short period is likely to produce misleadingly high levels of immediate mastery that will not survive the passage of substantial periods of time”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Educational Implications
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: The 32 obscure trivia facts and object names used in the study are representative of the kinds of information people need to learn and retain in educational settings.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“If a person wishes to retain information for several years, a delayed review of at least several months seems likely to produce a highly favorable return on a time investmentpotentially doubling the amount ultimately remembered, holding study time constant-as compared to less temporally distributed study.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Educational Implications
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: The 32 obscure trivia facts and object names used in the study are representative of the kinds of information people need to learn and retain in educational settings.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Whether or not this conclusion stands, it seems likely that the data provide significant new constraints on theorizing about spacing over meaningful time intervals.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Theoretical Implications
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: unclear — It is unclear whether it could be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: The 26 gap-by-retention interval combinations adequately sample the retention surface.
A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“Theories that attribute effects of gap to a reduced likelihood of information residing in short-term memory, such as most forms of deficient processing theory (Jacoby, 1978;Rundus, 1971), would not seem to fit well with present data”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Theoretical Implications
What the sources say
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: Working memory operates on a time scale of seconds or minutes.
In the paper
“All-or-none theories (Estes, Hopkins, & Crothers, 1960), in which items are either learned or not learned on any given trial, may also be challenged by the present data.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Theoretical Implications
What the sources say
- Not checked — no full text of the sourcecites Estes, Hopkins, & Crothers, 1960 source
hedgedconditional- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In summary, while it is understandable for researchers to view webcollected data with initial caution, actual experience with these methods provides little reason to view web-collected data as any less credible than lab-collected data.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > In
plain- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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- It may state two separate claims as one. 9
- Probably not a substantial claim. 6
- The quote only partly states this claim. 1
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“A recent review of distributed practice studies involving verbal recall (Cepeda et al., 2006) examined more than 400 papers.However, only about a dozen of these looked at retention intervals as long as one day, with just a handful examining retention intervals longer than one week.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Spacing Effects in Learning 2
What the sources say
- Partly supportedcites Cepeda et al., 2006 sourceExperimental — accuracy not yet measured
Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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It may state two separate claims as one.
- Partly supported
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The optimum gap value was about 20% of the test delay for delays of a few weeks, falling to about 5% when delay was one year.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Abstract
plaincorrelationaln = 1,350- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In Figure 4, for example, the optimal gap for RI = 350 equals 23 days, which is just 7% of the RI.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Discussion
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“First, for any gap duration, recall performance must decline as a function of RI (i.e., test delay) in a negatively accelerated fashion in order to produce the familiar forgetting curve consistent with more than 100 years of memory findings.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Discussion
boosteddirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper may give no reason why it holds.
- Rests on an assumption: The forgetting curve is negatively accelerated (information loss per unit time gradually shrinks).
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The results presented here document the existence of enormous and non-monotonic spacing effects that unfold over very long periods of time, with study time equated across conditions.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Discussion
boostedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Exploration of the data indicated that a number of other functions can also provide quite decent fits to the data, with various tradeoffs between interpretability of parameters and simplicity of the function, and we do not contend that this function offers a uniquely accurate characterization of the surface-merely a reasonable one.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Discussion
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“There were 26 gap-by-retention interval combinations, and each subject was randomly assigned to one of these.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Stimuli and materials.
plain- Asserted: passes — The authors put it forward as true.
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Probably not a substantial claim.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“There were also no detectable differences between the groups in age, gender, number of obscure facts known before beginning the study, or a wide array of background and demographic characteristics.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Subjects.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“We held constant the number of restudy trials in the second study session, thus allowing us to look at the effect of gap apart from the amount of time provided for restudy.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Spacing Effects in Learning 2
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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Probably not a substantial claim.
In the paper
“The results showed that increasing the inter-study spacing out to 56 days improved performance (Figure 2).”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Spacing Effects in Learning 2
What the sources say
- Not checked — no full text of the sourcecites Bahrick et al., 1993 source
plaindirectn = 4- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
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The quote only partly states this claim.
In the paper
“The non-monotonic pattern noted in short-term studies was indeed found: Recall success (for both facts and names) was best for a 1-month gap, with much worse recall for shorter gaps and slightly poorer recall for longer ones.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Preliminary Data
What the sources say
- Not matchedcites Cepeda et al., 2007
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plaincorrelationaln = 150- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Not matched
In the paper
“However, 56 days is actually a relatively short proportion of the extremely long retention intervals used in Bahrick et al.'s study, and it is this ratio that is probably most critical, as will emerge below.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Spacing Effects in Learning 2
What the sources say
- Not checked — no full text of the sourcecites Bahrick et al., 1993 source
hedgedcorrelationaln = 4- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Non-completion rates increased at the longer delays, as one would expect in any multi-year study (Table 1)”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Subjects.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
None of the sources cited for this claim have been checked yet.
In the paper
“As described in the Appendix, the reliability and validity of internet data collection has become increasingly clear in recent years.”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Spacing Effects in Learning 2
What the sources say
- Not matchedcites Reips, 2002
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- Not checked — no full text of the sourcecites Gosling et al., 2004 source
boosted- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
- Not matched
None of the sources cited for this claim have been checked yet.
In the paper
“The validity of internet testing has been well supported in recent reviews (Gosling et al., 2004), with excellent correspondence between results obtained with internet samples are results obtained in the laboratory (e.g., Birnbaum, 1999;Krantz & Dalal, 2000;McGraw, Tew, & Williams, 2000;Reips, 2002).”
§ OPTIMIZING RETENTION USING DISTRIBUTED PRACTICE Spacing effects in learning: A temporal ridgeline of optimal retention > Appendix: Comments and Validity of Internet Memory Testing Data
What the sources say
boostedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper relies on this without support.
The 32 obscure trivia facts and object names used in the study are representative of the kinds of information people need to learn and retain in educational settings.
“Stimuli consisted of 32 obscure but true trivia facts (e.g.,”
The paper relies on this without support.
The forgetting curve is negatively accelerated (information loss per unit time gradually shrinks).
“The amount of information lost per unit of time gradually shrinks, producing the well-known increasingly gradual forgetting curve.”
The paper relies on this without support.
Working memory operates on a time scale of seconds or minutes.
“Working memory operates on a time scale of seconds or minutes, whereas gap effects are seen on a scale of day and weeks (optimal gap is several weeks, for longer retention intervals).”
The paper relies on this without support.
The 26 gap-by-retention interval combinations adequately sample the retention surface.
“To properly characterize the interaction of gap and retention interval, the current study combines various gap and RI values, for a total of 26 different conditions.”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The cited source doesn’t support the claim as written.
In the citing paper
“The optimal ratio of spacing and retention interval should be 10-30%.”
From MASSED TASK REPETITION IS A DOUBLE-EDGED SWORD FOR FLUENCY DEVELOPMENT: AN EFL CLASSROOM STUDY (2022) · cites this paper as Cepeda et al., 2008
Checked by a reasoning model — may be wrong.
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“However, such research also emphasizes that the effect of retention intervals on the distributed practice advantage does not continuously increase as the retention interval increases (Cepeda et al., 2008).”
From The Distributed Practice Effect on Classroom Learning: A Meta-Analytic Review of Applied Research (2025) · cites this paper as Cepeda et al., 2008
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“There are two issues: (1) learning is not spaced-out despite evidence that enduring retention is achieved through substantial gaps in practice (gaps of months to achieve knowledge lasting years) (Cepeda et al., 2008);”
From Using version control to document genuine effort in written assignments: a protocol with examples for universities (2023) · cites this paper as Cepeda et al., 2008
Experimental — accuracy not yet measuredThe cited source says what the claim attributes to it.
In the citing paper
“According to cognitive psychologists (Cepeda et al., 2008;Rohrer & Pashler, 2007), the optimal spacing depends on the retention interval (i.e., the timing of delayed posttest).”
From MASSED TASK REPETITION IS A DOUBLE-EDGED SWORD FOR FLUENCY DEVELOPMENT: AN EFL CLASSROOM STUDY (2022) · cites this paper as Cepeda et al., 2008
Citations
Cites
From dissertation abstracts international
(1974) · ACM SIGGRAPH Computer Graphics · doi:10.1145/988616.988619 · Cited by 12,208
Editorial Office (1997) · Obesity Surgery · doi:10.1381/096089297765555359 · Cited by 3,941
Gosling, S. D., Vazire, S., Srivastava, S., & John, O. P. (2004) · American Psychologist · doi:10.1037/0003-066x.59.2.93 · Cited by 2,932
Distributed practice in verbal recall tasks: A review and quantitative synthesis.
Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D. (2006) · Psychological Bulletin · doi:10.1037/0033-2909.132.3.354 · Cited by 1,888
Self-citationSchmidt, R. A., & Bjork, R. A. (1992) · Psychological Science · doi:10.1111/j.1467-9280.1992.tb00029.x · Cited by 1,582
Principles of Learning and Memory
Murdock, B. B., & Crowder, R. G. (1977) · The American Journal of Psychology · doi:10.2307/1422060 · Cited by 1,306
Standards for Internet-Based Experimenting
Reips, U. (2002) · Experimental Psychology (formerly Zeitschrift für Experimentelle Psychologie) · doi:10.1026/1618-3169.49.4.243 · Cited by 878
Analysis of rehearsal processes in free recall.
Rundus, D. (1971) · Journal of Experimental Psychology · doi:10.1037/h0031185 · Cited by 797
On interpreting the effects of repetition: Solving a problem versus remembering a solution
Jacoby, L. L. (1978) · Journal of Verbal Learning and Verbal Behavior · doi:10.1016/s0022-5371(78)90393-6 · Cited by 667
Standards for Internet-Based Experimenting
Reips, U.-D. (2002) · Experimental Psychology · doi:10.1026//1618-3169.49.4.243 · Cited by 469
Research works printed but not linked: 2
- Murray J.T., 1983, Dissertation Abstracts International, 43, 3058
- Young J.L., 1966, Dissertation Abstracts International, 27, 3699
Cited by
Sorted by citations
Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J., & Willingham, D. T. (2013) · Psychological Science in the Public Interest · doi:10.1177/1529100612453266 · Cited by 3,138
The critical role of retrieval practice in long-term retention
Roediger, H. L., & Butler, A. C. (2011) · Trends in Cognitive Sciences · doi:10.1016/j.tics.2010.09.003 · Cited by 1,796
Carpenter, S. K., Cepeda, N. J., Rohrer, D., Kang, S. H. K., & Pashler, H. (2012) · Educational Psychology Review · doi:10.1007/s10648-012-9205-z · Cited by 469
Self-citationSpaced Repetition Promotes Efficient and Effective Learning: Policy Implications for Instruction
Kang, S. H. K. (2016) · Policy Insights from the Behavioral and Brain Sciences · doi:10.1177/2372732215624708 · Cited by 408
What makes distributed practice effective?
Benjamin, A. S., & Tullis, J. (2010) · Cognitive Psychology · doi:10.1016/j.cogpsych.2010.05.004 · Cited by 323
Metadata
- Authors
- Cepeda, N. J., Vul, E., Rohrer, D., Wixted, J. T., & Pashler, H.
- Affiliations
- York University (CA)
- University of California San Diego (US)
- University of South Florida (US)
- Corresponding author
- Pashler, Harold
- Venue
- Psychological Science
- Publisher
- SAGE Publications
- Published
- 2008-11
- Volume
- 19
- Issue
- 11
- Pages
- 1095-1102
- ISSN
- 0956-7976 (ISSN-L)
- 1467-9280
- OpenAlex
- W2169419728
- Cited by
- 631
- References
- 32
- Citations by year
- 2026: 41 · 2025: 54 · 2024: 52 · 2023: 39 · 2022: 51 · 2021: 54 · 2020: 38 · 2019: 49 · 2018: 36 · 2017: 27 · 2016: 25 · 2015: 31 · 2014: 34 · 2013: 25 · 2012: 44
- FWCI
- 5.17
- Type
- journal article
- Language
- en
- Open access
- green
- escholarship.org
- Locations
- Psychological Science (publishedVersion)
- PubMed (publishedVersion)
- eScholarship (California Digital Library) (submittedVersion)
- Digital Commons - University of South Florida (University of South Florida) (submittedVersion)
- Funders
- National Science Foundation (0542013, 0720375)
- U.S. Department of Education
- Institute of Education Sciences
- Topics
- Life Sciences › Neuroscience › Cognitive Neuroscience › Memory Processes and Influences
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Visual and Cognitive Learning Processes
- Life Sciences › Neuroscience › Cognitive Neuroscience › Memory and Neural Mechanisms
- Keywords
- spacing effect, retention, test delay, spaced learning, long-term memory
- MeSH terms
- Adolescent, Adult, Aged, Female, Humans, Learning, Male, Memory, Middle Aged, Retention, Psychology, Space Perception, Time Factors, Young Adult
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
A language model drew the claims from the paper on 2026-10-12, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).
A second model labelled each claim on 2026-10-12 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).
Cited sources are checked with a language model’s help (gpt-6-sol).
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
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