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Cited by 910Cognitive Abilities and TestingCognitive and developmental aspects of mathematical skillsDevelopmental and Educational Neuropsychology

Working Memory Training Does Not Improve Performance on Measures of Intelligence or Other Measures of “Far Transfer”

Open access
Melby-Lervåg, Monica, Redick, Thomas S., Hulme, Charles·2016·Perspectives on Psychological Science
DOI 10.1177/1745691616635612PMC PMC4968033
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Abstract

It has been claimed that working memory training programs produce diverse beneficial effects. This article presents a meta-analysis of working memory training studies (with a pretest-posttest design and a control group) that have examined transfer to other measures (nonverbal ability, verbal ability, word decoding, reading comprehension, or arithmetic; 87 publications with 145 experimental comparisons). Immediately following training there were reliable improvements on measures of intermediate transfer (verbal and visuospatial working memory). For measures of far transfer (nonverbal ability, verbal ability, word decoding, reading comprehension, arithmetic) there was no convincing evidence of any reliable improvements when working memory training was compared with a treated control condition. Furthermore, mediation analyses indicated that across studies, the degree of improvement on working memory measures was not related to the magnitude of far-transfer effects found. Finally, analysis of publication bias shows that there is no evidential value from the studies of working memory training using treated controls. The authors conclude that working memory training programs appear to produce short-term, specific training effects that do not generalize to measures of “real-world” cognitive skills. These results seriously question the practical and theoretical importance of current computerized working memory programs as methods of training working memory skills.

Verified 2026-10-05 · 1 reference not checked yet

Integrity signals

Registry

Crossref · 10.1177/1745691616635612

Cites

231 of 232 references verified0 citation errors · 0 not checkable

Statistics

3 tests recomputed · 0 with the reported and recomputed p on opposite sides of .05

Claims the paper makes

11 of 73 cited sources checked · 6 supported · 1 flagged · accuracy not yet measured

  • Findingown data

    The follow-up arithmetic effect seems driven by three comparisons across two studies where the control group shows decreases between pretest and posttest.

    “Unfortunately, once again this effect seems to be driven by three comparisons across two studies (Nussbaumer et al., 2013; Alloway et al., 2013) where the control group shows decreases in performance between pretest and posttest.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites Nussbaumer et al., 2013

      The Discussion (page unavailable) says the low-WM-load group was the active control group and that its performance increased from pretest to posttest, rather than decreased. The Results (page unavailable) also report no differential transfer in mathematical problem-solving tasks. This paper does not establish the citing sentence’s count of three comparisons across two studies. (LLM, conf=0.87)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
    • cites Alloway et al., 2013 source
  • Interpretationreasoning

    These crossover interactions artificially produced large effect sizes and are responsible for the significant effect of N-back training and transfer to nonverbal ability.

    “These crossover interactions thus artificially produced large effect sizes (Boot, Blakely, & Simons, 2011; Fischer-Baum, 2015; Redick, 2015; Redick & Webster, 2014), and are responsible for the significant effect of N-back training and transfer to nonverbal ability.”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Boot, Blakely, & Simons, 2011 source

      In 'Inadequate Baseline for Transfer Effects' (page unavailable), the paper says a control group’s lack of expected test–retest improvement can make a training benefit appear greater. That supports the general concern about inflated apparent effects, but the passage does not identify crossover interactions, quantify large effect sizes, or link them to N-back training and transfer to nonverbal ability. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites Fischer-Baum, 2015

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Redick, 2015 source
  • Findingown data

    After removing the most problematic study (Schweizer et al., 2011), the effect of N-back training on nonverbal ability with treated controls is negligible (g = 0.10).

    “After only the most problematic study has been removed from the analysis (Schweizer et al., 2011), the effects of N-back training on nonverbal ability with treated controls is negligible (g = 0.10).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Schweizer et al., 2011 source
  • Findingown data

    Six comparisons across four studies show control group decreases in reading comprehension from pretest to posttest.

    “Of these, 6 comparisons across 4 studies (Jaeggi et al 2014; Lee, 2014; Redick & Wiemers, 2015; Shiran & Breznitz, 2011) show an odd pattern with the control group showing decreases in reading comprehension from pretest-posttest”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Jaeggi et al 2014 source
    • cites Lee, 2014
    • cites Redick & Wiemers, 2015 source

      The Criteria for Evaluating Educationally-Relevant Working Memory Training Research section says that control groups sometimes decline from pretest to posttest. But our copy does not report six reading-comprehension comparisons across four studies; the specific control-group decreases described in the Alloway et al. (2013) section concern spelling and math. No page numbers are available in our copy. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
  • Interpretationcitation

    Task- or stimulus-specific strategies probably explain much of the pretest-to-posttest improvement for intermediate and near transfer to verbal and visuospatial working memory tasks.

    “For intermediate and near transfer effects to verbal and visuo-spatial working memory tasks, the development of task- or stimulus-specific strategies is likely to explain a large amount of the pretest-to-posttest improvement (Gibson et al., 2014; Dunning & Holmes, 2014; Sprenger et al., 2013).”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Gibson et al., 2014 source
    • cites Dunning & Holmes, 2014 source

      The Discussion reports that strategy use and performance improved together on untrained visuospatial short-term memory and verbal working memory tasks that directly overlapped with training, and proposes task-specific strategies as an explanation. It does not establish how much of the improvement strategies explain, and the Results do not show a comparable strategy increase for visuospatial working memory in the adaptive-training group. Page numbers are unavailable in our copy. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites Sprenger et al., 2013 source
  • May combine two claims. 41
  • Classified as probably not a substantial claim. 44

  • May combine two claims.

    Premisecitation

    Intervention studies are especially prone to publication bias and poor replicability.

    “Several studies have found that intervention studies are particularly vulnerable to publication bias and for lacking replicability (Cuijpers et al., 2010; Scherer et al., 2007).”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites Cuijpers et al., 2010 source
    • cites Scherer et al., 2007 source

      The discussion passage on randomized or controlled trials reports that positive results were associated with full publication and warns reviewers of interventions about publication bias (page not provided). It does not address replicability or establish that intervention studies are more vulnerable to publication bias than other study designs. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    There is a significant effect at follow-up for treated controls on arithmetic.

    “There is, however, a significant effect at follow-up for treated controls on arithmetic.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    When comparisons with problematic control-group pretest-to-posttest decline are excluded, the reading comprehension effect for treated controls becomes trivial (g = 0.08) and similar to other far transfer outcomes.

    “When the comparisons with the problematic pretest-to-posttest decline in the control group are excluded, the effects of working memory training compared to treated controls for reading comprehension becomes trivial (g = 0.08) and similar in magnitude to the”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Findings are consistent between studies; there is no significant variation between studies on any measure at follow-up.

    “The findings are consistent between studies; there is no significant variation between studies on any measure.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingreasoning

    Both significant moderator effects include problematic comparisons, and when those studies are excluded the effect sizes reduce to trivial levels.

    “however, both of these significant effects within the moderator analyses include the problematic comparisons described above, and when these studies are excluded the effect sizes reduce to trivial levels.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Working memory training effects on verbal and visuo-spatial working memory measures are significant, moderate in size, and show true heterogeneity between studies.

    “These effects are significant, moderate in size, and there is evidence of true heterogeneity between studies (see Table 1).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Four of the five largest comparisons had large, unexplained pretest-to-posttest decreases for the control group, larger than the training group's increases.

    “In addition, 4 of the 5 comparisons had large, unexplained pretest-to-posttest decreases for the control group, which were larger than the training group's pretest-to-posttest increases.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In studies with treated controls, training effects on nonverbal ability, verbal ability, word decoding, and arithmetic are close to zero and not significant.

    “In studies with treated controls, the effects of training on nonverbal ability, verbal ability, word decoding, and arithmetic are close to zero and not significant (see Table 1).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Near transfer findings vary across studies (true heterogeneity present) and are maintained at follow-up.

    “The findings, though statistically significant, vary across studies (true heterogeneity is present, see Table 1) and are maintained at follow-up (5 months after training; see Table 2).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    There was a tendency for grey literature studies to have smaller effect sizes, significant only for verbal working memory and visuo-spatial working memory.

    “Overall, there was a tendency for studies in the grey literature to have smaller effect sizes, but this was only significant for verbal working memory and visuo-spatial working memory”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    On most measures, the pattern of findings across studies was consistent; true variation between studies was zero or not significant.

    “On most measures the pattern of findings across studies were consistent (the true variation between studies was zero or not significant, see Table 1).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    At follow-up, verbal working memory effects were no longer significant in studies with treated controls but remained significant for untreated controls.

    “At follow-up the effects for verbal working memory were no longer significant in studies with treated controls, but still significant for studies with untreated controls.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    For treated controls at follow-up, there are no statistically significant effects on nonverbal ability, verbal ability, word decoding, or reading comprehension.

    “For treated controls there are no statistically significant effects on nonverbal ability, verbal ability, word decoding, or reading comprehension.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Current working memory training programs yield short-term improvements on both verbal and visuo-spatial working memory tasks.

    “Current working memory training programs yield short-term improvements on both verbal and visuo-spatial working memory tasks.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Although the meta-analytic effects were mostly nonsignificant, some individual studies did show transfer.

    “As is evident in our figures, even though the meta-analytic effect sizes tended to be non-significant, there are certainly individual studies that demonstrate transfer effects.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    For visuo-spatial working memory, modest training effects appear maintained at follow-up, but outcome tasks often share features with trained tasks.

    “For measures of visuo-spatial working memory, modest training effects appear to be maintained at follow-up, but these outcome tasks often share features (memoranda, method) with the tasks trained.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    For treated controls, studies meeting the minimum sample size produced no effect (g = .01), whereas comparisons with fewer subjects produced a significant effect (g = .26).

    “For treated controls, the k = 34 studies meeting the minimum recommended sample sizes produced no effect, g = .01, whereas the k = 25 comparisons with fewer subjects produced a significant effect, g = .26.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Based on analysis of 87 studies containing 145 independent experiments, the authors observed no evidence that working memory training increases intelligence or other real-world skills.

    “However, based on an analysis of the 87 studies containing 145 independent experiments reviewed here, we observed no evidence of such effects.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Neither the reading comprehension nor the arithmetic effect was significant in untreated control comparisons.

    “In addition, neither of these effects was significant in the untreated control comparisons.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    There were two cases of weak evidence for transfer: reading comprehension immediately after training (not sustained at follow-up) and arithmetic at follow-up (without immediate posttest effects).

    “There were two cases where there appears to be weak evidence for transfer from working memory training to measures of “real-world” cognitive skills: improvements in reading comprehension immediately after training (that were not sustained at follow-up) and improvements in arithmetic at follow-up (in the absence of effects at immediate posttest).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The largest effect size for working memory training on nonverbal ability came from the earliest study (d = 2.18; Klingberg et al., 2002), which had only 7 subjects per group.

    “The largest effect size for working memory training on nonverbal ability came from the earliest study (d = 2.18; Klingberg et al., 2002), which included only 7 subjects in each of the training and control groups.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Klingberg et al., 2002 source

  • May combine two claims.

    Findingown data

    For untreated controls, studies meeting the minimum sample size produced a significant effect (g = .16), as did comparisons with fewer subjects (g = .33).

    “For untreated controls, the k = 31 studies meeting the minimum recommended sample sizes produced a significant effect, g = .16, as did the k = 18 comparisons with fewer subjects, g = .33.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Immediate and delayed comparisons for nonverbal ability, verbal ability, reading comprehension, word decoding, and arithmetic were all nonsignificant against treated controls after outliers were removed.

    “all immediate and delayed comparisons of nonverbal ability, verbal ability, reading comprehension, word decoding, and arithmetic were not significantly different from zero when compared against treated controls and eliminating outlier studies.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    They did find significant moderator effects on intermediate and near transfer, suggesting sufficient power to detect such effects if present.

    “We did find significant moderator effects on intermediate and near transfer (verbal and visuo-spatial working memory), suggesting that we had sufficient power to detect such effects if they were present.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    This larger sample should yield more robust effect size estimates and more powerful moderator analyses.

    “This will give us much more robust estimates of effect size, and allow us to perform moderator analyses that have more power.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    Outcome coding had an inter-rater correlation of r = .99, 95% CI [.97, 1], p < .0001, and 97.00% agreement.

    “The inter-rater correlation (Pearson's) for outcomes was r = .99, 95% CI [.97, 1], p < .0001 and agreement rate = 97.00%.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Moderator coding had 98% agreement.

    “For the moderators, the agreement rate was 98%.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductreasoning

    Duplicate samples were checked by examining studies from the same author, and participants appearing in more than one study were coded once.

    “For this reason studies from the same author were examined to detect duplicate samples, and studies based on the same participants were only coded once”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The meta-analysis followed PRISMA guidance for systematic reviews.

    “This meta-analysis was designed in line with the statement for systematic reviews developed by PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses, www.prisma-statement.org).”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Studies with treated controls and studies with untreated controls were analyzed in separate groups.

    “Since previous meta-analyses have found a large difference between studies using treated and untreated controls (Dougherty et al., 2015; Lilienfeld et al. 2014; Melby-Lervåg & Hulme, 2013), these two designs were analyzed separately.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Dougherty et al., 2015

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Lilienfeld et al. 2014 source
    • cites Melby-Lervåg & Hulme, 2013 source

  • Probably not a substantial claim: may not pass S1 (asserted).

    Premisecitation

    One theory holds that fluid intelligence differences largely reflect working memory capacity differences.

    “For example, according to one theory variations in fluid intelligence reflect to a large degree variations in working memory capacity (Engle, 2002; but see Heitz et al., 2006).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Engle, 2002 source

  • May combine two claims.

    Premisecitation

    Conflicting prior reviews may stem from biased methodological choices and from focusing on restricted subsets of studies.

    “Previous reviews seem to show conflicting findings for two main reasons: First, some methodological decisions may have led to biased conclusions (see Melby-Lervåg & Hulme, 2015). Secondly, typically previous reviews have examined subsets of studies restricted to specific types of working memory training, age groups, or participant status.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Melby-Lervåg & Hulme, 2015 source

  • Classified as probably not a substantial claim.

    Premisecitation

    Working memory limits may constrain many higher cognitive functions.

    “The idea that working memory limitations may place constraints on diverse higher cognitive functions leads directly to the suggestion that if working memory capacity can be increased by training, this should produce transfer effects to diverse untrained tasks that depend on such a capacity (Shipstead, Redick, & Engle, 2010).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Shipstead, Redick, & Engle, 2010 source

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    If working memory training raises fluid intelligence or attainment without raising working memory capacity, that pattern would be theoretically difficult to explain.

    “If working memory training studies find increases in fluid intelligence or attainment in the absence of increases in working memory capacity, this pattern would be difficult to explain theoretically.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisereasoning

    Klingberg et al. (2002) had very small groups (7 children each) and was severely underpowered.

    “However, there are some obvious weaknesses in this study: the group sizes (7 children per group) are tiny – this study is, like many other studies in this area, severely underpowered.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Klingberg et al. (2002) source

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    For a construct with multiple indicators, the indicators were averaged into one effect size per study.

    “When a study had multiple indicators for the same construct (for instance more than one measure of verbal working memory) the mean of the indicators was used to yield a single effect size, for that study.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Moderator analyses were omitted for follow-up effects, decoding, reading comprehension, and arithmetic because too few comparisons were available.

    “Because of the limited number of training studies examining follow-up effects, moderator analyses were not conducted. In addition, moderator analyses were not calculated for decoding, reading comprehension, and arithmetic, given the limited number of comparisons for treated and untreated controls.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Effect sizes were computed as the treatment-control difference in pretest-posttest gain divided by the pooled pretest standard deviation, following Morris (2008).

    “We calculated effect sizes by dividing the differences in gain between pre- and post-test in the treatment and the control group by the pooled standard deviation for each group at pretest; this method of effect size calculation for pretest-posttest designs is recommended (Morris, 2008).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Morris, 2008 source

  • May combine two claims.

    Interpretationown data

    Working memory training appears to yield short-term, task-specific benefits that do not extend to real-world cognitive skills.

    “The authors conclude that working memory training programs appear to produce short-term, specific training effects that do not generalize to measures of “real-world”cognitive skills.”
    • Also stated in: § Abstract · plain
      “Our conclusion is that there is no good evidence that working memory training improves intelligence test scores or other measures of “real-world”cognitive skills.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S1 (asserted).

    Premisecitation

    If training can raise working memory capacity, it should transfer to various untrained tasks that depend on that capacity.

    “The idea that working memory limitations may place constraints on diverse higher cognitive functions leads directly to the suggestion that if working memory capacity can be increased by training, this should produce transfer effects to diverse untrained tasks that depend on such a capacity (Shipstead, Redick, & Engle, 2010).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Shipstead, Redick, & Engle, 2010 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Two independent raters coded all studies.

    “All the studies were coded by two independent raters.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Increases in working memory capacity are typically thought to mediate the effects of working memory training on fluid intelligence or academic attainment.

    “This is because effects of working memory training on fluid intelligence or academic attainment are typically seen as being mediated by (i.e. dependent upon) increases in working memory capacity (Harrison et al., 2013; Lange & Süß, 2015; Tidwell et al., 2014; von Bastian & Oberauer, 2014).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Harrison et al., 2013 source
    • cites Lange & Süß, 2015 source
    • cites Tidwell et al., 2014 source

  • Probably not a substantial claim: may not pass S1 (asserted).

    Premisecitation

    Working memory capacity limits may contribute to reading, language, and mathematics impairments.

    “Others have argued that limitations in working memory capacity may be responsible for impairments in the development of reading (Swanson, 2006), language (Archibald & Gathercole, 2006), and mathematical skills (Passolunghi, 2006).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Swanson, 2006

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Archibald & Gathercole, 2006 source
    • cites Passolunghi, 2006

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Mean effect sizes were weighted averages from a random-effects model.

    “The mean effect sizes were calculated by a weighted average of individual effect sizes using a random-effects model.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    Meta-analysis may help clarify conclusions from inconsistent findings in underpowered research.

    “Because studies in this area are generally underpowered, summarizing them in a meta-analysis may be valuable as a way of clarifying the conclusions that can be drawn from the many inconsistent findings.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Computing an overall effect size from the same sample more than once violates independence and can bias estimates.

    “Violating the assumption of independence by computing an overall effect size based on information from the same sample more than once can lead to biased estimates (Borenstein et al. 2007).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Borenstein et al. 2007

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationnone given

    If working memory training improved intelligence test scores, it would have major implications for education, economic productivity, and cognitive theory.

    “Nevertheless, if the claim that working memory training improves intelligence test scores could be confirmed and substantiated it would have potentially important implications for education and economic productivity, as well as for theories about the nature and limitations of human cognitive abilities.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    Small-sample adjustment used Hedges g.

    “We adjusted the effect size for small samples using Hedges g (Hedges & Olkin, 1985).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Hedges & Olkin, 1985 source

  • Classified as probably not a substantial claim.

    Premisereasoning

    Far transfer effects are expected only when working memory capacity increases.

    “Theoretically, such far transfer effects are only expected in the presence of improvements in working memory capacity.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    Decreases in a stable construct like reading comprehension in a control group between pretest and posttest can only reflect measurement error.

    “Theoretically, there is no reason to expect decreases in a relatively stable construct such as reading comprehension ability between pretest and posttest in a control group; such decreases presumably can only reflect error of measurement.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisereasoning

    If true effects exist, published p-values should be right-skewed with more low than high p-values.

    “If there are true effects, one expects the distribution of published p-values to be right-skewed with more low (.01s) than high (.04s) p-values.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductcitation

    This review will emphasize publication bias by retrieving grey literature and estimating its impact statistically.

    “Here, we will pay particular attention to this, both by retrieving as much grey literature as possible (see Rothstein, Sutton & Borenstein, 2005) and by estimating the impact of publication bias using statistical procedures.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Rothstein, Sutton & Borenstein, 2005

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    P-curve is a recently developed method that addresses weaknesses in funnel plot/trim-and-fill analysis.

    “P-curve is a recently developed method that deals with the weaknesses in the funnel plot/trim- and-fill analysis (Simonsohn, Nelson & Simmons, 2014).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Simonsohn, Nelson & Simmons, 2014 source

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    A p-curve plots the distribution of statistically significant p values in published studies, and its shape depends only on effect size and sample size when power is accounted for.

    “A p-curve plots the distribution of statistically significant p values (p < 0.05) in published studies, and the shape of the p-curve is a function only of the effect size and sample size, when the power level is taken into account.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Simonsohn, Nelson & Simmons, 2014 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductcitation

    The authors made special efforts to retrieve studies from the grey literature and used publication type as a moderator where possible.

    “In line with recommendations for meta-analyses, we made special efforts to retrieve studies from the grey literature and used this as a moderator when possible (Higgins & Green, 2011).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Higgins & Green, 2011

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationcitation

    These effect sizes are arguably too small to be relevant to educational practice.

    “In any case, these effect sizes are arguably too small to be relevant to educational practice (Promising Practices Network [PPN], 2007; What Works Clearinghouse, 2007; Cooper, 2008).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Promising Practices Network [PPN], 2007

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites What Works Clearinghouse, 2007

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Cooper, 2008 source

  • Classified as probably not a substantial claim.

    Premisenone given

    If studies are affected by publication bias, the p-curve becomes left-skewed or flat.

    “However, if a set of studies is affected by publication bias (because researchers discard entire studies or discard analyses or parts of studies), the p-curve becomes left-skewed or flat.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    This review will provide finer-grained analysis of working memory measures and publication bias than prior reviews.

    “Further, in comparison to Melby-Lervåg and Hulme (2013) and Schwaighofer et al. (2015), we will also provide a more fine-grained analysis of working memory measures and publication bias.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Melby-Lervåg and Hulme (2013) source
    • cites Schwaighofer et al. (2015) source

  • Classified as probably not a substantial claim.

    Premisereasoning

    A left-skewed or flat p-curve provides no evidential value for an appreciable effect size.

    “Such a form of p-curve is said to provide “no evidential value” (i.e., no support for an appreciable effect size).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Random assignment is traditionally considered the surest way to ensure that intervention results reflect a causal effect.

    “Traditionally, it has been argued that random allocation of participants to conditions is the surest way of ensuring that the results of an intervention reflect a causal effect (Shadish, Cook, & Campbell, 2002).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Shadish, Cook, & Campbell, 2002

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    People of high and low ability may use cognitive resources differently on the same complex task, so repeated practice may not tax the same processes equally across individuals.

    “As noted elsewhere (Logie, 2012), high- and low-ability individuals performing the same complex task may strategically use their cognitive resources differently so that repeatedly practicing the same task over sessions may not address the same cognitive processes to the same degree across all people.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Logie, 2012 source

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    Untreated control comparisons overestimate the true effects of working memory training.

    “since these studies are likely to show evidential value because the untreated control comparison overestimates the “true” effects of intervention.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationown data

    The lack of significant moderator effects on nonverbal ability is important because it contradicts many suggestions in the literature.

    “We believe that the lack of significant moderator effects on nonverbal ability is important since it contradicts many suggestions in the literature.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    The overall pattern from this meta-analysis agrees with an earlier review.

    “Our meta-analysis included an impressive number of studies from the burgeoning working memory training literature, but the pattern of results is consistent with an earlier review (Melby-Lervåg & Hulme, 2013).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Melby-Lervåg & Hulme, 2013 source

  • May combine two claims.

    Interpretationreasoning

    Declines in controls on stable constructs like reading comprehension and arithmetic are unexpected and presumably reflect measurement error.

    “This pattern of declines in the controls on stable constructs such as reading comprehension and arithmetic is completely unexpected and presumably reflects measurement error.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Whether an active control group uses a non-adaptive training regime or a different adaptive activity may have effects.

    “For example, whether an active control group uses a non-adaptive training regime or a different, adaptive activity may have effects (Weicker et al., 2015).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Weicker et al., 2015

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationown data

    The treated-control p-curve is flat or slightly left-skewed, providing evidence of publication bias.

    “The p-curve is flat or slightly left-skewed, providing evidence of publication bias (exclusion of whole studies or parts of studies).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    Many reviewed studies did not describe the active control group scheme in much detail, so there were too few studies for a more fine-grained analysis.

    “Because many of the studies reviewed did not describe the active control group scheme in much detail, there were too few studies to do a more fine-grained”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Both effects appear driven by studies where the control group decreases from pretest to posttest, and such a pattern inflates effect size estimates.

    “Both effects appear to be driven by studies in which the control group show a decrease between pretest to posttest, and such a pattern inflates estimates of the effect size obtained”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Simmons et al. (2011) recommend at minimum 20 subjects/observations in each cell.

    “Simmons et al. (2011) recommend that at a minimum, 20 subjects/observations need to be present in each cell (in this case, group).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Simmons et al., 2011 source

  • May combine two claims.

    Premisecitation

    Intensive targeted educational interventions can improve word reading difficulties and reading and language comprehension problems.

    “In this vein, there is good evidence that difficulties with word reading and problems with reading and language comprehension can be improved by intensive, targeted educational interventions (see Hulme & Melby-Lervåg, 2015).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Hulme & Melby-Lervåg, 2015 source

  • Classified as probably not a substantial claim.

    Premisecitation

    Individual differences in working memory capacity have multiple facets.

    “This result may reflect the fact that individual differences in working memory capacity are multi-faceted (Gibson & Gondoli, 2012, 2013).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Gibson & Gondoli, 2012, 2013

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Kraemer et al. (1998) argued that meta-analyses should exclude underpowered studies to reduce misleading conclusions from the file drawer problem.

    “Kraemer, Gardner, Brooks, and Yesavage (1998) have argued forcefully that meta-analyses should exclude studies that are underpowered, as this will go a long way to removing the problem of misleading conclusions arising from the file drawer problem.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Kraemer, Gardner, Brooks, and Yesavage, 1998 source

  • Classified as probably not a substantial claim.

    Premisereasoning

    If working memory training produces far transfer via increased working memory capacity, there should be a direct relationship between working memory skill increases and far transfer increases.

    “If working memory training produces far transfer because of increased working memory capacity, there should be a direct relationship between the degree to which working memory skills increase and the extent of increases in measures of “far transfer” such as fluid intelligence.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    This is termed a winner's curse because such very large effect sizes are unlikely to be true.

    “This is termed by Bogg and Lasecki (2014) a “winner's curse” because such very large effect sizes are unlikely to be true.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Bogg and Lasecki, 2014

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The type of active control group used is potentially important.

    “It should also be noted that the type of active control group used is also potentially important (see Mohr et al., 2009).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Mohr et al., 2009 source

  • May combine two claims.

    Interpretationown data

    These results provide clear evidence that nonverbal ability transfer is largest in studies with untreated controls and small sample sizes, and no effects are observed in studies with treated controls and at least the minimum recommended sample size.

    “These results provide clear evidence that nonverbal ability transfer is largest in studies with untreated controls and small sample sizes, and no effects are observed in studies with treated controls and at least the minimum recommended number of subjects in the training and control groups.”
    Quote in the paperSubstantial claim
77 of 77

  • The authors state this as an assumption.

    The multiple comparisons from the same control group included in one analysis have zero correlation between their outcomes.

    “we choose to include these studies in the analyses assuming zero correlation between the outcomes.”

  • The authors state this as an assumption.

    Individuals with cognitive impairments may benefit more from working memory training.

    “Under the assumption that individuals who have cognitive impairments (e.g., ADHD, dyslexia, low working memory, or other neuropsychological disorders) may be more receptive to benefits from working memory training”
2 of 2

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?

  • Multiple meta-analyses have reported that true heterogeneity in working memory training, both within and between studies, is null or low.

    “Interestingly, several meta-analyses have estimated within-and between-study true heterogeneity in WM training to be null or low, both with near-transfer and far-transfer effects.”

    From Working memory training in typically developing children: A multilevel meta-analysis (2020) · cites this paper as Melby-Lervåg et al., 2016

    The Results section, “Effects of Working Memory Training on Near Transfer Measures” (page unavailable), explicitly says near-transfer findings vary across studies and that true heterogeneity is present. The Results also report true heterogeneity between studies for intermediate-transfer measures. Thus, this paper contradicts the claim that heterogeneity is null or low across transfer outcomes; a near-zero far-transfer effect is not the same as low heterogeneity. (LLM, conf=0.88)

    Checked by a reasoning model — may be wrong.

    Experimental — accuracy not yet measured

  • Previous meta-analytic near transfer measures have lumped together untrained WM tasks that differ from training tasks only by stimuli and WM tasks structurally different from training tasks.

    “Third, meta-analytic near transfer measures have lumped together untrained WM tasks that differ from the training tasks only by their stimuli and WM tasks that are structurally different from the training tasks”

    From Working memory training revisited: A multi-level meta-analysis of n-back training studies (2017) · cites this paper as Melby-Lervåg et al., 2016

    The Method section (Search, Inclusion Criteria and Coding; page not available) says this meta-analysis separated near-transfer tests similar or identical to trained tasks from an intermediate category of other working-memory measures. It does not lump those categories together as the claim says. (LLM, conf=0.84)

    Checked by a reasoning model — may be wrong.

    Experimental — accuracy not yet measured

  • A meta-analysis reported a trend for n-back being the most efficient WM training.

    “Importantly, a meta-analysis reported a trend for n-back being the most efficient WM training [13].”

    From Adaptive working memory training does not produce transfer effects in cognition and neuroimaging (2022) · cites this paper as [13]

    The Results (Immediate Effects on Intermediate Transfer Measures; page unavailable) report that CogMed, not N-back, had a significantly larger effect on verbal working memory than the other training programs. The Results (Immediate Effects on Far Transfer Measures; page unavailable) attribute N-back’s apparent effect on nonverbal ability to problematic studies and say it became negligible when the most problematic study was removed. The paper therefore does not report a trend establishing N-back as the most efficient working-memory training. (LLM, conf=0.85)

    Checked by a reasoning model — may be wrong.

    Experimental — accuracy not yet measured

  • Prior meta-analyses found no far-transfer effects on other cognitive or academic skills, especially when active controls are used.

    “Both meta-analyses reach the conclusion that while WM training exerts a medium effect on memory-task performance (near transfer), no other cognitive or academic skills (far transfer) seem to be affected, regardless of the population examined; in particular, no effects are observed when active controls are implemented to rule out placebo effects”

    From Working memory training in typically developing children: A multilevel meta-analysis (2020) · cites this paper as Melby-Lervåg et al., 2016

    The Results (Immediate Effects of Working Memory Training on Far Transfer Measures; page unavailable) find near-zero, nonsignificant effects for several cognitive and academic outcomes with treated controls, supporting the main far-transfer conclusion. But they also report a small, significant reading-comprehension effect before excluding problematic comparisons, so “no effects” is too absolute. The Results (Effects of Working Memory Training on Near Transfer Measures; page unavailable) describe near-transfer effects as large, rather than medium. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • Prior meta-analyses found that working memory training has a medium effect on near-transfer memory tasks.

    “Both meta-analyses reach the conclusion that while WM training exerts a medium effect on memory-task performance (near transfer), no other cognitive or academic skills (far transfer) seem to be affected, regardless of the population examined; in particular, no effects are observed when active controls are implemented to rule out placebo effects”

    From Working memory training in typically developing children: A multilevel meta-analysis (2020) · cites this paper as Melby-Lervåg et al., 2016

    The Results section reports significant, moderate effects on verbal and visuo-spatial working-memory measures, supporting the claim that training benefits memory-task performance. But it classifies those measures as intermediate transfer; its separate near-transfer section describes large effects on tasks similar or identical to those trained. The claimed effect size therefore does not match the paper’s near-transfer category. Page numbers were not available in our copy. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

Statistics that don’t add up

Each reported p-value recomputed from its test statistic and degrees of freedom.

  • Inconsistent p-value: Q(1) = 13.70, p = .0001

    Minor

    The paper reports p = .0001 here; recomputing from the test statistic and its degrees of freedom gives p < .001. The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p = .0001 · recomputed p < .001

1 of 1

Statistics recomputed

Every reported test result, recomputed from its test statistic and degrees of freedom. A result shows as not adding up only once an independent check has confirmed it.

  • Doesn’t add upQ(1) = 13.7reported p = .0001 · recomputed p < .001

    “Q(1) = 13.70, p = .0001”

  • ConsistentQ(1) = 6.09reported p = .01 · recomputed p = .014

    “Q (1) = 6.09, p = .01”

  • ConsistentQ(1) = 4.52reported p = .03 · recomputed p = .034

    “Q(1) = 4.52, p = .03”

3 of 3

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Control-group coefficient has the opposite sign from the reported effect

    Minor

    The regression codes treated controls as 1 and untreated controls as 0, so a positive coefficient indicates larger nonverbal-ability gains with treated controls. The paper instead says treated controls showed smaller gains. The second regression also reports a positive coefficient for control type.

1 of 1

Cited works that were retracted

Works this paper cites that were later retracted, from the retraction notices publishers deposit. Major when the notice came out before this paper was published.

  • Cites a retracted work: 10.1111/j.1467-9280.2008.02172.x

    Major

    The cited work was retracted on 2011-03-31 (notice 10.1177/0956797611404902), before this paper was published (2016-07). Its authors could have known.

    Cited work 10.1111/j.1467-9280.2008.02172.x · retracted 2011-03-31 · notice 10.1177/0956797611404902 · this paper published 2016-07

  • Cites a retracted work: 10.1073/pnas.1018601108

    Info

    The cited work was retracted on 2025-05-01 (notice 10.1073/pnas.2508040122), not before this paper was published (2016-07).

    Cited work 10.1073/pnas.1018601108 · retracted 2025-05-01 · notice 10.1073/pnas.2508040122 · this paper published 2016-07

2 of 2

Cites

2 retracted

Flagged first, then by citations

Research works printed but not linked: 17

  1. *Alloway T. P., 2012, Journal of Interactive Learning Research, 23, 197
  2. 10.1037/00332909.128.4.612 · DOI
  3. Borenstein M., 2005, Comprehensive meta-analysis (Version 2) [Software]
  4. Buschkuehl M., 2010, Swiss Medical Weekly, 140, 266
  5. *Feiyue Q., 2009, The 1st international conference on information science and engineering, 3459
  6. 10.371/journal.pone.0007141
  7. *Horvat M. (2014). Vpliv treninga delovnega spomina na kognitivne sposobnosti [The effect of working memory training on cognitive abilities] (Master’s thesis). University of Maribor, Slovenia. (Grey)
  8. **Netto T. M., 2013, Psychology: Reflection and Review, 26, 122
  9. Passolunghi M. C., 2006, Working memory and neurodevelopmental condition, 113
  10. *Redick T. S., 2015, Poster present at the Annual Meeting of the Association for Psychological Science
  11. 10.1037/0022006x.64.6.1290 · DOI
  12. *Shavelson R. J., 2008, Contributions of educational psychology to changing institutions, environments, and people, 1
  13. Unsworth N., 2015, Reasoning as memory, 9
  14. *Weicker J., 2013, Poster presented at the 4th Joint Meeting of the European Societies of Neuropsychology (ESN) and the 28th Meeting of the German Society of Neuropsychology (GNP)
  15. 10.1037/neu00002 · DOI
  16. *Zhang Q., 2014, Poster presented at the 26th annual convention of the Association for Psychological Science
  17. 10.1159/000324240007 · DOI

Cited by

Sorted by citations

Related

Authors
Melby-Lervåg, M., Redick, T. S., & Hulme, C.
Affiliations
  • Department of Special Needs Education, University of Oslo
  • Purdue University West Lafayette (US)
  • University of Oslo (NO)
Corresponding author
Redick, Thomas S.
ORCID
Venue
Perspectives on Psychological Science
Publisher
SAGE Publications
Published
2016-07
Volume
11
Issue
4
Pages
512-534
ISSN
  • 1745-6916 (ISSN-L)
  • 1745-6924
DOI
10.1177/1745691616635612
PMC
PMC4968033
OpenAlex
W2480700159
Semantic Scholar
57a161286f16efa63b0704de7a0a219ef8c9a24b
Cited by
910
References
212
Citations by year
2026: 63 · 2025: 82 · 2024: 75 · 2023: 78 · 2022: 84 · 2021: 111 · 2020: 126 · 2019: 94 · 2018: 99 · 2017: 63 · 2016: 15
FWCI
122.98
Type
journal article
Language
en
Open access
Licence
Locations
  • Perspectives on Psychological Science (publishedVersion, cc-by-nc)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion, cc-by-nc)
  • Research Bank (Australian Catholic University) (submittedVersion)
  • UCL Discovery (University College London) (submittedVersion)
Topics
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Cognitive Abilities and Testing
  • Physical Sciences › Mathematics › Statistics and Probability › Cognitive and developmental aspects of mathematical skills
  • Social Sciences › Psychology › Neuropsychology and Physiological Psychology › Developmental and Educational Neuropsychology
Keywords
working memory training, far transfer, intelligence, nonverbal ability, verbal ability, word decoding, reading comprehension, arithmetic
MeSH terms
Cognitive Remediation, Humans, Intelligence, Memory, Short-Term, Transfer, Psychology

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.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-05.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-05.

Cited sources are checked by 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.

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