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Cited by 104Attention Deficit Hyperactivity DisorderNeural and Behavioral Psychology StudiesDevelopmental and Educational Neuropsychology

Decomposing attention-deficit/hyperactivity disorder (ADHD)-related effects in response speed and variability.

Open access
Karalunas, Sarah L., Huang-Pollock, Cynthia L., Nigg, Joel T.·2012·Neuropsychology
DOI 10.1037/a0029936PMC PMC3516369
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Abstract

OBJECTIVE: Slow and variable reaction times (RTs) on fast tasks are such a prominent feature of attention-deficit/hyperactivity disorder (ADHD) that any theory must account for them. However, this has proven difficult because the cognitive mechanisms responsible for this effect remain unexplained. Although speed and variability are typically correlated, it is unclear whether single or multiple mechanisms are responsible for group differences in each. RTs are a result of several semi-independent processes, including stimulus encoding, rate of information processing, speed-accuracy trade-offs, and motor response, which have not been previously well characterized. METHOD: A diffusion model was applied to RTs from a forced-choice RT paradigm in two large, independent case-control samples (NCohort 1 = 214 and NCohort 2 = 172). The decomposition measured three validated parameters that account for the full RT distribution and assessed reproducibility of ADHD effects. RESULTS: In both samples, group differences in traditional RT variables were explained by slow information processing speed, and unrelated to speed-accuracy trade-offs or nondecisional processes (e.g., encoding, motor response). CONCLUSIONS: RT speed and variability in ADHD may be explained by a single information processing parameter, potentially simplifying explanations that assume different mechanisms are required to account for group differences in the mean and variability of RTs.

AI snapshot

Written from the paper’s full text.

TL;DR

Diffusion modeling in two independent case-control samples found that ADHD-related slower and more variable responses were explained by slower information accumulation (drift rate), not by speed-accuracy trade-off or non-decision processes. The authors suggest a single processing parameter may account for both mean and variability effects in ADHD.

Key findings

  • In Cohort 1 (214 children: 164 ADHD, 50 controls), the ADHD group had lower go-trial accuracy (d = 0.28) and greater RT variability (d = 0.48), with no mean RT difference; diffusion analysis showed slower drift rate (d = 0.34) but no group differences in boundary separation or non-decision time.
  • In Cohort 2 (172 children: 81 ADHD, 91 controls), the ADHD group again had lower accuracy (d = 0.65) and greater RT variability (d = 0.78), with no mean RT difference; drift rate was slower (d = 0.68), while boundary separation and non-decision time did not differ.
  • Group effects on accuracy, RT variability, and drift rate did not significantly differ by cohort, though Cohort 1 had lower accuracy, less RT variability, faster drift, older age, lower estimated IQ, and more families below the federal poverty limit than Cohort 2.
  • The authors conclude that slow drift rate may be a single mechanism underlying ADHD-related response speed and variability, potentially linked to neural signal-to-noise ratio.

Methods

  • Two independent case-control cohorts were recruited in different cities/states using identical screening and diagnostic procedures; diagnoses used parent/teacher rating scales, a semi-structured clinical interview, IQ testing, and clinical team consensus.
  • Participants completed a tracking stop task; analyses used go trials (75% of trials) requiring an X/O choice response, with 32 practice trials and 4 blocks of 64 experimental trials. Diffusion parameters—drift rate, boundary separation, and non-decision time—were estimated from full correct and error RT distributions using Fast-dm; anticipation RTs under 150 ms were removed.
  • MANCOVAs compared ADHD and control groups on mean RT, RT SD, accuracy, and the three diffusion parameters, with age and estimated IQ as covariates; gender, ODD symptoms, and medication status were initially considered but dropped as non-significant.

Limitations

  • The paper states that cohort differences in task performance and drift rate were not explained by age, IQ, or income and likely reflect unmeasured sampling or procedural variation; additional samples are needed to estimate the population effect.
  • The paper notes that the diffusion model may not capture attention lapses or contaminant RTs, that stop-task demands may affect speed-accuracy and motor preparation strategies, and that the model addresses single-step decisions rather than multi-step problem solving.
  • Evident from the text: the cohorts differed in age range (7–18 vs. 7–12) and sample composition, and ADHD subtypes were collapsed after showing no outcome differences, which may limit generalization across developmental stages and subtype-specific effects.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1037/a0029936

Cites

83 of 83 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 88 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    In Cohort 1, children with ADHD were less accurate than controls (F[1,210]=4.12, p=.044, d=0.28).

    “Children with ADHD were less accurate (F[1, 210]= 4.12, p= .044, d= 0.28)”
    Quote in the paperNot a substantial claim
  • Findingown data

    In Cohort 1, there were significant between-group differences on traditional task performance measures (mean RT, SD RT, accuracy) after age and IQ covariates.

    “a MANCOVA that included mean RT, standard deviation of RT, and percent accuracy as between-groups measures, with age and estimated IQ as covariates, indicated significant between-groups differences on traditional task performance measures (F[3,208]= 3.55, p= .015)”
    Quote in the paperSubstantial claim
  • Findingown data

    The two cohorts differed significantly on task performance measures, including RT standard deviation and drift rate.

    “Significant differences between the two cohorts were identified in task performance measures, including for standard deviation of RT and drift rate.”
    Quote in the paperNot a substantial claim
  • Findingown data

    In Cohort 1, groups did not differ in mean reaction times.

    “Groups did not differ in mean RTs (see Table 1).”
    Quote in the paperSubstantial claim
  • Findingown data

    The current study found no group differences in non-decision times in either sample.

    “In regards to non-decision time, the current study found no group differences in non-decision times in either sample.”
    Quote in the paperSubstantial claim
  • May combine two claims. 28
  • The quote only partly states this claim. 9
  • Classified as probably not a substantial claim. 26

  • May combine two claims.

    Findingown data

    In both cohorts, ADHD was associated with slower drift rate despite no mean RT differences, and the drift-rate effect size was comparable to that for RT standard deviation, with overlapping confidence intervals in both cohorts.

    “In both cohorts, slow drift rate was detected in the absence of differences in mean RT and the effect size was similar to that of standard deviation of RT (with substantially overlapping confidence intervals for drift rate and standard deviation of RT in both cohorts).”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingown data

    In Cohort 1, groups did not differ in non-decision time (p > .157).

    “but did not differ in either their speed-accuracy trade-off setting or non-decision time (all p> .157; see Table 1)”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: In a diffusion model, information about a stimulus is accumulated via a noisy process until a decision criterion is met, at which point a response is initiated.
    • The authors state this as an assumption: Participants in forced-choice tasks set criteria for how much information they require before committing to a response.
    • The authors state this as an assumption: Individuals who require less information respond more quickly but make more errors than those who require more information.
    • The authors state this as an assumption: Processes not directly related to the response decision, such as stimulus encoding and motor preparation, influence final reaction time and must be modeled.

  • May combine two claims.

    Findingown data

    Across both cohorts, children with ADHD have slower or less efficient information processing speed, but do not differ from controls in speed-accuracy trade-offs or non-decision times.

    “In both samples, group differences in traditional RT variables were explained by slow information processing speed, and unrelated to speed-accuracy trade-offs or non-decisional processes (e.g. encoding, motor response).”
    • Also stated in: § Discussion · hedged
      “Diffusion model analyses, which separately estimate the impact of information processing speed/efficiency, speed-accuracy trade-offs, and non-decisional processes (e.g. encoding, motor response), here indicate that children with ADHD have slower/less efficient information processing speed, but do not differ from non-ADHD controls in their speed-accuracy trade-offs or non-decision times.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: In a diffusion model, information about a stimulus is accumulated via a noisy process until a decision criterion is met, at which point a response is initiated.
    • The authors state this as an assumption: Participants in forced-choice tasks set criteria for how much information they require before committing to a response.
    • The authors state this as an assumption: Individuals who require less information respond more quickly but make more errors than those who require more information.
    • The authors state this as an assumption: Processes not directly related to the response decision, such as stimulus encoding and motor preparation, influence final reaction time and must be modeled.

  • The quote only partly states this claim.

    Findingown data

    In Cohort 2, groups did not differ in non-decision time (p > 0.381).

    “but did not differ in either speed-accuracy trade-off setting or non-decision times (all p> 0.381)”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: In a diffusion model, information about a stimulus is accumulated via a noisy process until a decision criterion is met, at which point a response is initiated.
    • The authors state this as an assumption: Participants in forced-choice tasks set criteria for how much information they require before committing to a response.
    • The authors state this as an assumption: Individuals who require less information respond more quickly but make more errors than those who require more information.
    • The authors state this as an assumption: Processes not directly related to the response decision, such as stimulus encoding and motor preparation, influence final reaction time and must be modeled.

  • The quote only partly states this claim.

    Findingown data

    In Cohort 2, groups did not differ in mean reaction times.

    “However, groups did not differ in their mean RTs (Table 2).”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingown data

    In Cohort 2, there were significant between-group differences on the three diffusion model parameters.

    “A MANCOVA that included all three diffusion model parameters as between-groups measures, with age and estimated IQ as covariates, indicated significant between-group differences (F[5,164]= 8.17, p< .001).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: In a diffusion model, information about a stimulus is accumulated via a noisy process until a decision criterion is met, at which point a response is initiated.
    • The authors state this as an assumption: Participants in forced-choice tasks set criteria for how much information they require before committing to a response.
    • The authors state this as an assumption: Individuals who require less information respond more quickly but make more errors than those who require more information.
    • The authors state this as an assumption: Processes not directly related to the response decision, such as stimulus encoding and motor preparation, influence final reaction time and must be modeled.

  • The quote only partly states this claim.

    Findingown data

    In Cohort 2, children with ADHD were less accurate than controls (F[1,168]=17.93, p<.001, d=0.65).

    “Children with ADHD were less accurate (F[1, 168]= 17.93, p< .001, d = 0.65)”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingown data

    In Cohort 2, groups did not differ in speed-accuracy trade-off setting (p > 0.381).

    “but did not differ in either speed-accuracy trade-off setting or non-decision times (all p> 0.381)”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: In a diffusion model, information about a stimulus is accumulated via a noisy process until a decision criterion is met, at which point a response is initiated.
    • The authors state this as an assumption: Participants in forced-choice tasks set criteria for how much information they require before committing to a response.
    • The authors state this as an assumption: Individuals who require less information respond more quickly but make more errors than those who require more information.
    • The authors state this as an assumption: Processes not directly related to the response decision, such as stimulus encoding and motor preparation, influence final reaction time and must be modeled.

  • The quote only partly states this claim.

    Findingown data

    In Cohort 2, children with ADHD had more variable reaction times than controls (F[1,168]=25.67, p<.001, d=0.78).

    “had more variable RTs (F[1, 168]= 25.67, p< .001, d = 0.78) than non-ADHD controls”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingown data

    In Cohort 1, there were significant between-group differences on the three diffusion model parameters after age and IQ covariates.

    “A MANCOVA that included the three diffusion model parameters as between-groups measures, with age and estimated IQ as covariates, indicated significant between-group differences (F[5,206]= 2.55, p= .029).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: In a diffusion model, information about a stimulus is accumulated via a noisy process until a decision criterion is met, at which point a response is initiated.
    • The authors state this as an assumption: Participants in forced-choice tasks set criteria for how much information they require before committing to a response.
    • The authors state this as an assumption: Individuals who require less information respond more quickly but make more errors than those who require more information.
    • The authors state this as an assumption: Processes not directly related to the response decision, such as stimulus encoding and motor preparation, influence final reaction time and must be modeled.

  • May combine two claims.

    Premisecitation

    The continuous performance tasks in that meta-analysis had rare targets and used single-choice reaction-time paradigms.

    “all of the CPTs included had rare targets (thus a small number of RTs) and used a single-choice RT paradigm”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Huang-Pollock et al., 2012

      Not checked in the free run.

  • May combine two claims.

    Study design and conductown data

    ADHD subtypes did not significantly differ on any outcome variables, so subtypes were collapsed into a single ADHD group.

    “In both samples, subtypes did not significantly differ on any of the outcome variables (mean RT, standard deviation of RT, accuracy, or the three diffusion model parameters), and so subtypes were collapsed into a single ADHD group for all analyses reported below.”
    Quote in the paperSubstantial claim

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

    Study design and conductown data

    In Cohort 1, the ADHD group had a higher proportion of children meeting ODD criteria than controls (p < .005).

    “The ADHD group also had a higher proportion of boys and a higher proportion of children meeting criteria for ODD than non-ADHD controls (all p < .005).”
    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

    No participants needed to be excluded because the diffusion model adequately fit the data (no significant Kolmogorov-Smirnov statistics).

    “Participants for whom the diffusion model was not able to adequately fit the data, as indicated by significant values for the Kolmogorov–Smirnov statistic, would have been excluded from analyses; however, no participants needed to be excluded for this reason.”
    Quote in the paperNot a substantial claim

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

    Study design and conductreasoning

    Age and IQ were included as covariates in the primary analyses.

    “Given well-known associations of age and IQ with speed and variability of RTs, results are reported with these covariates included.”
    Quote in the paperNot a substantial claim

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

    Study design and conductown data

    In Cohort 1, groups did not differ in age (p = .489).

    “Groups did not differ in age (p= .489)”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Diffusion models are well-validated and show strong convergent and divergent validity.

    “Diffusion models are well-validated and show strong convergent and divergent validity.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Voss et al., 2004

      Not checked in the free run.

    • cites Ratcliff, 2006

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    The sample for that third study was small, so the confidence interval around the effect is large.

    “The sample for the latter study was small, however, and so the confidence interval around the effect is large.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Mulder et al., 2010

      Not checked in the free run.

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

    Study design and conductown data

    In Cohort 1, the ADHD group had a higher proportion of boys than controls (p < .005).

    “The ADHD group also had a higher proportion of boys and a higher proportion of children meeting criteria for ODD than non-ADHD controls (all p < .005).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisereasoning

    The effect size for τ has not been directly compared with those for μ and σ, so it is unclear whether the τ effect is reliably larger.

    “the size of the effects for the three ex-Gaussian parameters have not been directly compared, and it is not clear if the effect for τ is reliably larger than for μ and σ”
    Quote in the paperSubstantial claim

  • May combine two claims. The quote only partly states this claim.

    Study design and conductnone given

    In Cohort 1, age, IQ, gender, ODD, and medication did not affect the reported results.

    “As noted above, these variables did not affect results reported.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Manipulations of stimulus quality uniquely influence drift rate, and manipulations of motor response complexity uniquely influence non-decision time.

    “Manipulations of stimulus quality uniquely influence drift rate and manipulations of motor response complexity uniquely influence non-decision time”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Voss et al., 2004

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Diffusion models were developed to explain decision-making in forced-choice paradigms requiring relatively rapid responses of about one second.

    “diffusion models have been developed to explain decision-making in forced-choice paradigms for which relatively rapid (~1 second) response decisions are required”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Ratcliff & Rouder, 1998

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Anticipation reaction times below 150 ms were removed because they negatively impact diffusion parameter estimation.

    “Anticipation RTs (those <150ms) were removed from the distribution because these outlier RTs negatively impact estimation of the diffusion parameters”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Vandekerckhove & Tuerlinckx, 2007

      Not checked in the free run.

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

    Study design and conductown data

    Agreement between diagnostic team members was acceptable for ADHD diagnosis (both kappas > .75) and for other disorders with >5% base rate (all kappas > .70).

    “agreement ratings between the members of the diagnostic team were acceptable for ADHD diagnosis (both kappas > .75) and for other disorders with >5% base rate in the sample (all kappas >.70)”
    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

    Gender, ODD symptoms, and medication status did not significantly contribute to the model (all p > .428), so results are reported without these covariates.

    “Gender composition, parent-reported symptoms of oppositional defiant disorder (ODD), and medication status were also initially included as covariates to ensure they did not account for the results. However, none significantly contributed to the model (all p> .428) and so results reported are without these covariates.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Diagnoses were established via a multi-gate process using parent and teacher standardized rating scales and a semi-structured clinical interview.

    “diagnoses were established via a multi-gate process. A parent/guardian and teacher completed standardized rating scales”
    • Also stated in: § Participants and Diagnostic Procedures · plain
      “The parent/guardian also completed a semi-structured clinical interview administered by a Master’s-level clinician who had achieved research reliability on the interview”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Achenbach & Rescorla, 1991

      Not checked in the free run.

    • cites Conners, 2003

      Not checked in the free run.

    • cites Kaufman et al., 1997

      Not checked in the free run.

  • May combine two claims.

    Study design and conductown data

    Diffusion parameter estimates did not differ when stop+1 trials were included versus excluded (all interactions p > .07, η2 < .03), so results are reported with stop+1 trials included.

    “because diffusion parameters estimates did not differ when stop+1 trials were included/excluded (all interactions with stop+1 trial presence were non-significant at p >.07, η2 < .03), the results reported are with the stop+1 trials included”
    Quote in the paperNot a substantial claim

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

    Premisereasoning

    The processes responsible for slow and variable reaction times in ADHD remain in need of further clarification.

    “Thus, the processes responsible for slow and variable RTs in ADHD remain in need of further clarification.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    Speed-accuracy trade-off is not a primary explanation for ADHD-related RT variability effects, because robust group differences in variability occurred in the current study without such trade-offs.

    “Overall, we conclude that speed-accuracy trade-off is not a primary explanation for ADHD-associated effects related to RT variability because robust group differences in variability were seen in the current study even in the absence of these trade-offs.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Drift rate is hypothesized to reflect signal:noise ratio in neural networks supporting decision-making.

    “Within a diffusion model framework, drift rate is hypothesized to reflect signal:noise ratio in the neural networks supporting decision-making”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Beck et al., 2008

      Not checked in the free run.

    • cites Ratcliff et al., 2003

      Not checked in the free run.

    • cites Heekeren et al., 2008

      Not checked in the free run.

  • May combine two claims.

    Study design and conductown data

    In Cohort 2, groups did not differ in age or estimated IQ (all p > 0.10).

    “Groups did not differ in their age or estimated IQs (all p> 0.10).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    The present results offer a clarification and possibly a more robust parameter for modeling ADHD cognitive processing, though direct effect-size comparisons across diffusion, ex-Gaussian, and signal detection parameters are still needed.

    “Thus, the present results provide a clarification and, perhaps, a more robust parameter for use in modeling ADHD cognitive processing in future work, although direct comparison of the size of effects for diffusion, ex-Gaussian, and signal detection parameters will be needed.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    The d′ parameter is vulnerable to artifact when error rates deviate markedly from 50%, which is common in ADHD cognitive-task studies.

    “However, as noted earlier, the d′ parameter is vulnerable to artifact when error rates depart markedly from 50%, which is often the case in ADHD studies using cognitive tasks.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    DLPFC structural and functional differences are associated with ADHD and with performance on cognitive-control tasks.

    “DLPFC structural and functional differences are also associated with ADHD and with performance on tasks demanding cognitive control (for reviews see Bush, Valera, & Seidman, 2005; Paloyelis, Mehta, Kuntsi, & Asherson, 2007).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Bush, Valera, & Seidman, 2005

      Not checked in the free run.

    • cites Paloyelis, Mehta, Kuntsi, & Asherson, 2007

      Not checked in the free run.

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

    Premisecitation

    Evidence from primate single-cell recordings, functional imaging, and human TMS suggests the DLPFC is involved in decision-making independent of stimulus modality and may compare inputs from modality-specific sensory neurons.

    “Initial evidence from direct single-cell recordings in primates (Kim & Shadlen, 1999), as well as functional imaging studies (Heekeren, Marrett, Bandettini, & Ungerleider, 2004; Heekeren, Marrett, Ruff, Bandettini, & Ungerleider, 2006) and transcranial magnetic stimulation studies in human(Philiastides, et al., 2011), suggests that the DLPFC is involved in decision-making independent of stimulus”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Kim & Shadlen, 1999

      Not checked in the free run.

    • cites Heekeren, Marrett, Bandettini, & Ungerleider, 2004

      Not checked in the free run.

    • cites Heekeren, Marrett, Ruff, Bandettini, & Ungerleider, 2006

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The only other diffusion modeling study in ADHD used a motion coherence paradigm and manipulated stimulus discrimination difficulty to be equivalent across participants, intentionally minimizing group differences in drift rate, preventing comparison.

    “The only other study applying diffusion modeling in ADHD used a motion coherence paradigm and specifically manipulated stimulus discrimination difficulty to be equivalent across participants, thereby intentionally minimizing group differences in drift rate, preventing comparison with current results”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Mulder et al., 2010

      Not checked in the free run.

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

    Study design and conductown data

    In Cohort 2, the ADHD group had a higher proportion of boys than controls (p < .007).

    “The ADHD group had a higher proportion of boys and a higher proportion of children meeting criteria for ODD than non-ADHD controls (all p < .007).”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Ex-Gaussian parameters lack clear cognitive interpretations, so upper-tail group differences are often interpreted as reflecting cognitive mechanisms distinct from those affecting the mean.

    “However, because ex-Gaussian parameters lack clear cognitive interpretations, group differences in the upper tail are often interpreted as reflecting unique cognitive mechanisms from those affecting the mean of the distribution(Hervey, et al., 2006; Leth-Steensen, et al., 2000).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Hervey, et al., 2006

      Not checked in the free run.

    • cites Leth-Steensen, et al., 2000

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The between-cohort differences were not explained by demographic differences such as age, estimated IQ, or income, and likely reflect unmeasured sampling variation or undetected procedural differences across sites.

    “These between-cohort difference could not be explained by sample differences in demographic characteristics, such as age, estimated IQ, or income, but instead likely reflect unmeasured sampling variation or undetected procedural variations across sites.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Some evidence suggests that children with ADHD do not differ at baseline in prioritizing speed over accuracy, but are less able than controls to adjust speed-accuracy settings across contexts.

    “Thus, some of the evidence suggests that children with ADHD do not have baseline differences in their tendency to prioritize speed over accuracy, but are less able than non-ADHD controls to adjust speed-accuracy settings in different contexts (e.g., depending on instructional set).”
    Quote in the paperSubstantial claim

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

    Premisecitation

    The speed-accuracy trade-off parameter has been associated with activation in the basal ganglia.

    “while the speed-accuracy trade-off parameter has been associated with activation in the basal ganglia (Forstmann et al., 2008).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Forstmann et al., 2008

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    The results suggest a new phenotypic target for imaging analyses.

    “Results also suggest a new phenotypic target for imaging analyses.”
    Quote in the paperSubstantial claim

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

    Interpretationreasoning

    Estimating the population effect of drift rate in ADHD will require additional samples.

    “At the same time, this suggests that estimation of the population effect of drift rate in ADHD will require additional samples.”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    Although the data allow that between-group RT variability differences may be explained by slow drift rates, other factors not addressed by the diffusion model may also contribute to increased RT standard deviation in ADHD.

    “In particular, although based on our data it is possible that between-group differences in RT variability may be explained by slow drift rates, there may also be other factors contributing to increased standard deviation of RT in ADHD that the diffusion model does not address.”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    If a single mechanism is sufficient, only one parameter would be needed to address slow and variable RT in ADHD, simplifying neural and process models.

    “Thus, only one parameter would be needed to address slow and variable RT in ADHD, simplifying neural and process models.”
    Quote in the paperSubstantial claim

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

    Interpretationreasoning

    The demands of the stop task may alter motor preparatory processes, thereby affecting non-decision times.

    “Similarly, the demands of the stop task may change how motor preparatory processes are carried out, impacting non-decision times.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    Prior neuroscience studies lead to the inference that these results are consistent with ADHD-related white matter integrity findings and with functional imaging findings of an inability to suppress resting-state activation in ADHD.

    “Prior neuroscience studies lead us to infer that these results are consistent with ADHD-related findings in white matter integrity, as well as with functional imaging studies suggesting that children with ADHD showing an inability to suppress resting-state activation.”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    Slow or inefficient information processing speed is conceptually related to neural signal-to-noise ratio.

    “That, in turn, is conceptually related to neural signal:noise ratio.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Although the diffusion model may accurately estimate parameters in a stop task, it cannot answer how task context affects an individual's decision-making strategies when applied to a single task.

    “Thus, while the diffusion model may accurately produce parameter estimates when applied in the context of a stop task, it cannot answer questions about how the task context affects individual’s strategies for decision-making when applied to a single task.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    In the current sample, removing all trials immediately following a stop trial did not change the results, supporting the interpretation of parameter estimates from this task.

    “In the current sample, results did not change when we removed all trials immediately following a stop trial, supporting our interpretation of parameters estimates from this task”
    Quote in the paperSubstantial claim

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

    Premisecitation

    The diffusion model has been applied successfully to a wide range of tasks, including the stop task, with consistently good fit to the data.

    “The diffusion model has been applied successfully to a wide range of tasks including the stop task, with consistently good fit to the data (Ratcliff & McKoon, 2008).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Ratcliff & McKoon, 2008

      Not checked in the free run.

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

    Premisecitation

    Previous work in adults using the diffusion model suggests that individuals strategically adjust speed-accuracy trade-off settings on go trials to maximize inhibition on stop trials.

    “However, previous work in adults using the diffusion model suggests that individuals make strategic adjustments to their speed-accuracy trade-off settings on go trials to maximize their ability to inhibit responses on stop trials (Verbruggen & Logan, 2009).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Verbruggen & Logan, 2009

      Not checked in the free run.

53 of 53

  • The paper relies on this without support.

    Mean and variability of reaction time are highly correlated.

    “although mean and variability of RT are highly correlated”

  • The authors state this as an assumption.

    In a diffusion model, information about a stimulus is accumulated via a noisy process until a decision criterion is met, at which point a response is initiated.

    “a diffusion model assumes that information about a stimulus is accumulated via a noisy information accumulation process until a decision criterion is met, at which point a response is initiated”

  • The authors state this as an assumption.

    Participants in forced-choice tasks set criteria for how much information they require before committing to a response.

    “participants are assumed to set criteria for how much information they require to commit to either of the response options”

  • The authors state this as an assumption.

    Individuals who require less information respond more quickly but make more errors than those who require more information.

    “Individuals who require less information will respond more quickly but will also make more errors than those who require more information.”

  • The authors state this as an assumption.

    Processes not directly related to the response decision, such as stimulus encoding and motor preparation, influence final reaction time and must be modeled.

    “processes that are not directly related to the response decision, such as stimulus encoding and motor preparation, also influence the final RT and so must be modeled”

  • The paper relies on this without support.

    Traditional RT variables show broad patterns of association with structural and functional neuroimaging measures.

    “Whereas traditional RT variables show broad patterns of association with structural and functional neuroimaging measures”
6 of 6

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?

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.

  • Cohort 2 diffusion MANCOVA repeats the degrees-of-freedom mismatch

    Minor

    The two Cohort 2 MANCOVAs likewise have three outcomes and the same covariates, yet the diffusion test reports F[5,164] rather than degrees of freedom consistent with the traditional-measures test's F[3,166].

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 2

  1. Huang-Pollock CL Karalunas SL Tam H Moore AN in press Evaluating vigilance deficits in adhd: A meta-analysis of cpt performance Journal of Abnormal Psychology PMC3664643 22428793
  2. Karalunas SL Huang-Pollock CL (revise and resubmit) Integrating evidence of slow rts and impaired executive functions using a diffusion model framework Journal of Abnormal Child Psychology PMC3679296 23334775

Cited by

Sorted by citations

Related

Authors
Karalunas, S. L., Huang-Pollock, C. L., & Nigg, J. T.
Affiliations
Oregon Health & Science University (US)
ORCID
Venue
Neuropsychology
Publisher
American Psychological Association (APA)
Published
2012
Volume
26
Issue
6
Pages
684-694
ISSN
  • 0894-4105 (ISSN-L)
  • 1931-1559
DOI
10.1037/a0029936
PMC
PMC3516369
OpenAlex
W1967147115
Semantic Scholar
08e95afb83ba840c4b6c76a89b083d16fb4c5c88
Cited by
104
References
83
Citations by year
2026: 5 · 2025: 10 · 2024: 5 · 2023: 7 · 2022: 7 · 2021: 11 · 2020: 8 · 2019: 9 · 2018: 9 · 2017: 2 · 2016: 14 · 2015: 4 · 2014: 7 · 2013: 6
FWCI
3.86
Type
journal article
Language
en
Open access
Locations
  • Neuropsychology (publishedVersion)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (acceptedVersion)
  • PubMed Central (acceptedVersion)
Funders
National Institute of Mental Health (F32MH098632, R01MH059105, R01MH084947)
Topics
  • Health Sciences › Medicine › Psychiatry and Mental health › Attention Deficit Hyperactivity Disorder
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Neural and Behavioral Psychology Studies
  • Social Sciences › Psychology › Neuropsychology and Physiological Psychology › Developmental and Educational Neuropsychology
Keywords
attention deficit hyperactivity disorder, reaction time, response variability, diffusion models, processing speed, speed-accuracy trade-off, stimulus encoding, motor response
MeSH terms
Adolescent, Attention Deficit Disorder with Hyperactivity, Child, Female, Humans, Inhibition, Psychological, Male, Models, Psychological, Neuropsychological Tests, Psychiatric Status Rating Scales, Psychomotor Performance, Reaction Time, Cohort Studies, Case-Control Studies

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Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-06.

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