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Cited by 155Aging and Gerontology ResearchCognitive Abilities and TestingDementia and Cognitive Impairment Research

Cohort differences in cognitive aging and terminal decline in the Seattle Longitudinal Study.

Open access
Gerstorf, Denis, Ram, Nilam, Hoppmann, Christiane, Willis, Sherry L., Schaie, K. Warner·2011·Developmental Psychology
DOI 10.1037/a0023426PMC PMC3134559
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Abstract

Life span researchers have long been interested in how and why fundamental aspects of human ontogeny differ between cohorts of people who have lived through different historical epochs. When examined at the same age, later born cohorts are often cognitively and physically fitter than earlier born cohorts. Less is known, however, about cohort differences in the rate of cognitive aging and if, at the very end of life, pervasive mortality-related processes overshadow and minimize cohort differences. We used data on 5 primary mental abilities from the Seattle Longitudinal Study (Schaie, 2005) to compare both age-related and mortality-related changes between earlier born cohorts (1886-1913) and later born cohorts (1914-1948). Our models covary for several individual and cohort differences in central indicators of life expectancy, education, health, and gender. Age-related growth models corroborate and extend earlier findings by documenting level differences at age 70 of up to 0.50 SD and less steep rates of cognitive aging on all abilities between 50 and 80 years of age favoring the later born cohort. In contrast, mortality-related models provide limited support for positive cohort differences. The later born cohort showed steeper mortality-related declines. We discuss possible reasons why often reported positive secular trends in age-related processes may not generalize to the vulnerable segment of the population that is close to death and suggest routes for further inquiry.

Verified 2026-11-03 · 4 references not checked yet

AI snapshot

Written from the paper’s full text.

TL;DR

In the Seattle Longitudinal Study, later-born cohorts (1914–1948) had higher cognitive levels at age 70 and shallower age-related declines from 50 to 80 than earlier-born cohorts (1886–1913), but these advantages largely did not extend to terminal decline. In mortality-related models, positive cohort differences appeared only for verbal meaning, while later-born participants showed steeper terminal declines on four of five abilities.

Key findings

  • Age-related growth models showed later-born cohorts outperformed earlier-born cohorts at age 70 by up to 0.50 SD on four of five primary mental abilities, with cohort intercept differences ranging from 2.353 for fluency to 5.818 for reasoning; number ability was the exception.
  • Later-born cohorts also had shallower linear age-related declines on all five abilities, with effects ranging from 0.060 for number to 0.231 for verbal meaning, and less pronounced concave curvature on reasoning, number, and verbal meaning.
  • Mortality-related models provided limited support for positive cohort differences: later-born participants outperformed earlier-born participants at 3 years before death only on verbal meaning (γ07 = 2.660), with no significant cohort differences for spatial orientation, inductive reasoning, or word fluency.
  • Later-born participants scored 0.465 SD lower on number ability at 3 years before death and experienced steeper linear terminal decline on four of five abilities, with effect sizes from 0.247 for spatial orientation to 0.446 for number ability; they also showed greater convex curvature on all five abilities.

Methods

  • Data came from the Seattle Longitudinal Study, a cohort-sequential panel launched in 1956 with eight waves at 7-year intervals through 2005 (49 years). The analyzed subsample compared participants born 1886–1913 with those born 1914–1948; age models used N = 1,980 and terminal-decline models used N = 891.
  • Cognitive outcomes were five Thurstone Primary Mental Abilities subtests—spatial orientation, inductive reasoning, word fluency, number, and verbal meaning—scaled to T scores (M = 50, SD = 10).
  • Multilevel growth curve models estimated linear and quadratic change over age (centered at 70) and time to death (centered at 3 years before death), with cohort and covariates including education, circulatory disease, cancer, gender, and, for mortality models, age at study entry and age at death; models were fit with SAS Proc Mixed.

Limitations

  • The paper states that the SLS sample was recruited through one large HMO in the Pacific Northwest, was community-dwelling and approximately represented the upper 75% of the socioeconomic spectrum, and may not be equally representative of the cohorts; the later-born terminal subsample died at younger ages and may have been less healthy, and covariates may only partially capture selectivity.
  • The paper also states that terminal models had lower statistical power, fewer participants and observations, no more than five age-model and four mortality-model data points per person, 7-year measurement intervals that may miss accelerations, and quadratic models that may poorly approximate terminal decline as a phase transition; the study was descriptive rather than causal, lacked direct data on qualitative education, modeled health as ever-diagnosed rather than severity or decline, and examined only the cognitive domain.
  • Evident from the text: age and mortality models were based on different, only partly overlapping subsamples and were not directly compared, so age-related and terminal-decline findings are not within the same analytic sample.

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

Integrity signals

Registry

Crossref · 10.1037/a0023426

Cites

87 of 91 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

6 of 48 cited sources checked · 1 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    Cohort differences in rates of cognitive aging among SLS participants typically favored later born cohorts, particularly on reasoning and verbal meaning abilities.

    “Schaie, Willis, and Pennak (2005) reported cohort differences in rates of cognitive aging among SLS participants that typically favored later born cohorts, particularly on reasoning and verbal meaning abilities.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Schaie, Willis, and Pennak (2005) source

      In “Cohort Differences in Rate of Age-Related Change” (page unavailable), the paper reports a difference in aging trajectories between older cohorts, with the slope particularly favoring the later-born cohort for verbal meaning. It also reports gains in inductive reasoning for later-born cohorts, but describes those as differences in performance level, not clearly as differences in rates of cognitive aging. Thus the claim’s emphasis on reasoning as an aging-rate finding is not fully supported. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
  • Findingown data

    In the last years of life, no differences in average levels of cognitive functioning were apparent on three of the five PMAs.

    “In contrast, in the last years of life no differences in average levels of cognitive functioning were apparent on three of the five PMAs, and evidence of negative secular trends emerged.”
    Quote in the paperSubstantial claim
  • Findingown data

    No significant cohort differences in ability levels were found for spatial orientation, inductive reasoning, and word fluency.

    “no significant cohort differences in ability levels were found for spatial orientation, inductive reasoning, and word fluency.”
    Quote in the paperSubstantial claim
  • Findingown data

    The earlier born cohort primarily died in the 1980s or before (median year of death = 1987).

    “A second implication arising from the approach we chose to define our cohorts is that the earlier born cohort primarily died in the 1980s or before (median year of death = 1987), whereas the later born cohort primarily died in the 1990s or after (median year of death = 2001).”
    Quote in the paperSubstantial claim
  • Findingown data

    The later born cohort was characterized by greater convex curvature on all five abilities (e.g., reasoning: −0.014).

    “the later born cohort was characterized by greater convex curvature on all five abilities (e.g., reasoning: −0.014).”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. 41
  • May combine two claims. 24

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

    Premisecitation

    Men typically outperform women on tasks assessing visuospatial and arithmetic processing, whereas women typically outperform men on tasks involving reasoning and verbal abilities.

    “gender differences in cognitive functioning have long been documented, with men typically outperforming women on tasks assessing visuospatial and arithmetric processing, whereas women typically outperform men on tasks involving reasoning and verbal abilities”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites Maitland, Herlitz, Nyberg, Backman, & Nilsson, 2004 source

      The Discussion reports that women outperformed men on verbal fluency, supporting the verbal-ability portion of the claim. The paper's comparisons concern declarative memory; the passages do not establish a female advantage in reasoning or a male advantage in visuospatial or arithmetic processing. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites Meinz & Salthouse, 1998 source

      The Gender Effects section reports a male advantage on spatial tasks, and the Discussion describes a male advantage on quantitative measures and reports prior findings of a female advantage in verbal abilities. But this study found that males outperformed females on reasoning tasks, while its differences in verbal fluency and knowledge were not significant. No page numbers are available in our copy. (LLM, conf=0.90)

      Experimental — accuracy not yet measured

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

    Premisecitation

    The rate of cognitive aging from age 55 to 87 on reasoning, spatial abilities, and vocabulary showed minimal if any differences between age-matched cohorts born 1893-1923 and 1908-1940.

    “Zelinski and Kennison (2007) applied growth models to data from the Long Beach Longitudinal Study (LBLS) and reported that the rate of cognitive aging from age 55 to age 87 on measures of reasoning, spatial abilities, and vocabulary showed minimal if any differences between age-matched cohorts born 1893–1923 and those born 1908–1940.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Zelinski and Kennison (2007) source

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

    Interpretationcitation

    Following notions of cognitive reserve, later born cohorts may enter phases of precipitous decline later than earlier born cohorts.

    “Following notions of cognitive reserve (Hall et al., 2009; Stern et al., 1999), later born cohorts may enter such phases of precipitous decline later than earlier born cohorts.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Hall et al., 2009 source

      The Results and Discussion (page unavailable) report that greater cognitive activity was associated with a later onset of accelerated memory decline among participants who developed dementia. The paper supports the cognitive-reserve rationale, but it does not compare earlier- and later-born cohorts or establish that later-born cohorts enter this phase later. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites Stern et al., 1999 source

  • Classified as probably not a substantial claim.

    Premisecitation

    Disability hazards are lower for later born cohorts.

    “empirical evidence indicates that disability hazards are indeed lower for later born cohorts”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Crimmins et al., 1996 source
    • cites Graham, Blakely, Davis, Sporle, & Pearce, 2004 source

      The Statistical methods section models mortality hazards but functional limitation prevalence, not disability hazards. The Changes between 1981 and 1996 section compares prevalence across survey years; it does not compare disability hazards by birth cohort. Searches for cohort-specific disability incidence and hazards found no such result in our copy. (LLM, conf=0.76)

      Experimental — accuracy not yet measured
    • cites Manton et al., 2008 source

  • May combine two claims.

    Findingown data

    Men outperformed women on measures of spatial orientation (γ04 = −2.745) and number (γ04 = −1.020).

    “the negative coefficient for gender indicates that men, on average, outperformed women on measures of spatial orientation (γ04 = −2.745) and number (γ04 = −1.020)”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    For cognitive aging, our results suggest systematic and substantial positive trends in cohort levels and in cohort changes.

    “For cognitive aging, our results suggest systematic and substantial positive trends in cohort levels and in cohort changes.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    With the exception of number ability, cohort differences in intercept ranged between 2.353 for fluency and 5.818 for reasoning, indicating that the later born cohort outperformed the earlier born cohort at age 70 by up to half a standard deviation.

    “With the exception of number ability, cohort differences in intercept ranged between 2.353 for fluency and 5.818 for reasoning, indicating that the later born cohort outperformed the earlier born cohort at age 70 by up to half a standard deviation.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The later born cohort was favored both in level of cognitive functioning at age 70 years and in rate of cognitive decline.

    “The later born cohort was favored both in level of cognitive functioning at age 70 years and in rate of cognitive decline.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Having died at an older age related to both lower levels of cognitive capacity at 3 years prior to death and steeper rates of terminal decline (e.g., for word fluency: γ02 = −0.276; γl2 = −0.006).

    “having died at an older age related to both lower levels of cognitive capacity at 3 years prior to death and steeper rates of terminal decline (e.g., for word fluency: γ02 = −0.276; γl2 = −0.006).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Cohorts differed significantly in linear rates of cognitive aging; effects ranged between 0.060 for number and 0.231 for verbal meaning, indicating shallower cognitive aging trajectories for SLS participants born in 1914 or later.

    “Cohorts also differed significantly in linear rates of cognitive aging. Effects ranged between 0.060 for number and 0.231 for verbal meaning, each being indicative of shallower cognitive aging trajectories for SLS participants born in 1914 or later.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    For terminal cognitive decline, our findings suggest a less optimistic outlook, with very little evidence of positive historical effects and several more consistent indications of negative secular trends.

    “For terminal cognitive decline, in contrast, our findings suggest a less optimistic outlook, with very little evidence of positive historical effects and several more consistent indications of negative secular trends.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    For reasoning, the linear decline was about a quarter of a standard deviation per 10 years (γ10 = −0.297), with concave curvature (γ20 = −0.007), bringing the average individual at age 70 (γ00 = 43.722) to more than half a standard deviation below the cross-sectional SLS mean.

    “the linear component of decline for reasoning amounted to about a quarter of a standard deviation per 10 years of age (e.g., γ10 = −0.297), which together with some concave curvature (γ20 = − 0.007) brought the average individual to an ability level at age 70 (γ00 = 43.722) that was more than half a standard deviation below the mean for all cross-sectional SLS participants”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Women performed better than men on tasks assessing reasoning (γ04 = 2.035), fluency (γ04 = 3.602), and verbal meaning (γ04 = 2.257).

    “the positive gender coefficient shows that women performed, on average, better than men on tasks assessing reasoning (γ04 = 2.035), fluency (γ04 = 3.602), and verbal meaning (γ04 = 2.257).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Average rates of mortality-related linear decline ranged between γ10 = −0.298 for reasoning and γ10 = −0.853 for verbal meaning, and all measures showed accelerations in decline (e.g., γ20 = −0.020 for verbal meaning).

    “average rates of mortality-related linear decline ranged between γ10 = −0.298 for reasoning and γ10 = −0.853 for verbal meaning, and all measures showed accelerations in decline (i.e., quadratic change, e.g., γ20 = −0.020 for verbal meaning).”
    Quote in the paperSubstantial claim

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

    Study design and conductnone given

    The study is primarily descriptive in nature and was not designed to tie cohort differences to particular causal mechanisms.

    “It must be noted that our study is primarily descriptive in nature and was not designed to tie cohort differences to particular causal mechanisms.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationreasoning

    Individuals in the later born cohort were more likely to die from aggressive forms of cancer and to experience steeper terminal decline.

    “It is possible, for example, that individuals in the later born cohort were more likely to die from aggressive forms of cancer and to experience steeper terminal decline.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Positive secular trends result in a delayed onset of chronic diseases and an increasingly short period of morbidity at the very end of life.

    “The broader conceptual argument for such an examination is borrowed from the compression-of-morbidity perspective, according to which positive secular trends result in a delayed onset of chronic diseases and an increasingly short period of morbidity at the very end of life (Fries, 1980).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Fries, 1980 source

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    To examine if secular trends emerge in terminal decline independent of known cohort differences, age at Time 1 and age at death were statistically controlled in the models.

    “To examine if secular trends emerge in terminal decline that are independent of known cohort differences, we statistically controlled for these differences in our models (i.e., age at Time 1 [T1] and age at death were used as covariates)”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    The models covary for several individual and cohort differences in central indicators of life expectancy, education, health, and gender.

    “Our models covary for several individual and cohort differences in central indicators of life expectancy, education, health, and gender.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    The later born cohort subsample was probably less representative and included relatively more unhealthy participants.

    “Although secular trends would have suggested longer life expectancies, participants in our later born cohort had died at younger ages than those in the earlier born cohort, suggesting that this subsample was probably less representative and included relatively more unhealthy participants.”
    Quote in the paperSubstantial claim

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

    Study design and conductnone given

    Interaction terms with the cohort variable were tested for all covariates, with only statistically significant terms retained in the final models.

    “Interaction terms with the cohort variable were tested for all covariates, with only statistically significant terms retained in the final models.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Quantitative differences in schooling may underlie cohort differences in intellectual performance.

    “Such quantitative differences in schooling may underlie cohort differences in intellectual performance (e.g., by promoting cognitive reserve; Rönnlund, Nyberg, Bäckman, & Nilsson, 2005; Stern, Albert, Tang, & Tsai, 1999).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Rönnlund, Nyberg, Bäckman, & Nilsson, 2005 source
    • cites Stern, Albert, Tang, & Tsai, 1999 source

  • May combine two claims.

    Interpretationown data

    Initial cohort differences in cognitive performance are maintained throughout aging and are even exacerbated with advancing age by shallower age-related declines among individuals born later.

    “Our analyses indicate that initial cohort differences in cognitive performance are maintained throughout aging and are even exacerbated with advancing age by shallower age-related declines among individuals born later.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductnone given

    Participants were community-dwelling individuals in reasonably good health who approximately represent the upper 75% of the socio-economic spectrum.

    “Participants were community-dwelling individuals in reasonably good health who approximately represent the upper 75% of the socio-economic spectrum.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Annual incidence rates for all forms of cancer had reached an all-time high for people who had entered old age in the 1980s and 1990s.

    “Annual incidence rates for all forms of cancer had reached an all-time high for people who had entered old age in the 1980s and 1990s (Altekruse et al., 2009).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Altekruse et al., 2009

      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).

    Premisecitation

    This finding is conceptually consistent with life span tenets about the vulnerabilities and constraints that appear in very old age and at the end of life.

    “Conceptually, this finding is consistent with life span tenets about the vulnerabilities and constraints that appear in very old age and at the end of life (Baltes & Smith, 2003).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Baltes & Smith, 2003 source

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

    Premisecitation

    Some studies have reported gender-differential cognitive change.

    “but some studies indeed have reported gender-differential change”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Schaie, 1994 source
    • cites Zelinski & Stewart, 1998 source

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

    Interpretationcitation

    A less positive selection of later born generations could have led to lower average levels of functioning for members of this generation, thereby offsetting positive secular trends.

    “A less positive selection of later born generations could have led to lower average levels of functioning for members of this generation, thereby offsetting positive secular trends.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Less consistent evidence has been gathered regarding gender differences in cognitive change in later adulthood and old age.

    “Less consistent evidence has been gathered regarding gender differences in cognitive change in later adulthood and old age”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Finkel, Reynolds, McArdle, Gatz, & Pederson, 2003 source

  • Classified as probably not a substantial claim.

    Premisecitation

    Health-related indices are among the factors most consistently linked to adult cognitive changes.

    “Given that health-related indices are among the factors most consistently linked to adult cognitive changes (for review, see Anstey & Christensen, 2000)”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Anstey & Christensen, 2000 source

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

    Interpretationcitation

    Positive secular trends for verbal meaning may simply have persisted because verbal abilities typically show particularly strong positive secular effect that may not get completely washed out by mortality effects.

    “If so, positive secular trends for verbal meaning may simply have persisted because verbal abilities typically show particularly strong positive secular effect (for a recent meta-analysis, see Uttl & Van Alstine, 2003) that may not get completely washed out by mortality effects.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Uttl & Van Alstine, 2003 source

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

    Interpretationnone given

    Verbal abilities are more likely to be 'practiced' until the end of life as compared with spatial abilities.

    “In a similar vein, verbal abilities are more likely to be “practiced” until the end of life as compared with, for example, spatial abilities.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Older adults typically show steep declines in cognitive functioning in the years before death.

    “It is well established in the cognitive literature that older adults typically show steep declines in cognitive functioning in the years before death (see Bäckman & MacDonald, 2006).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Bäckman & MacDonald, 2006 source

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

    Interpretationreasoning

    If participants in the later born cohort for the age models were indeed unhealthy, the positive secular trends documented over chronological age were underestimating effect sizes in the target population.

    “If participants in the later born cohort for the age models were indeed unhealthy, the positive secular trends documented over chronological age were underestimating effect sizes in the target population.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Number skills reached a peak with the 1924 birth cohort and showed negative cohort differences thereafter.

    “Previous, more fine-grained analyses had revealed that number skills reached a peak with the 1924 birth cohort and showed negative cohort differences thereafter.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Schaie, 1994, 2005

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

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

    Premisenone given

    The confounding of age effects and cohort effects constitutes a central threat to internal and external validity.

    “the confounding of age effects and cohort effects constitutes a central threat to internal and external validity”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    For the earlier born cohort, minor forms of disease may already implicate steep cognitive declines.

    “For the earlier born cohort, minor forms of disease may already implicate steep cognitive declines.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    Age and mortality models are based on different subsamples that only partly overlap, and the two change models were not directly compared with one another.

    “We note that age and mortality models are based on different subsamples that only partly overlap. Thus, the two change models were not directly compared with one another”
    Quote in the paperNot a substantial claim

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

    Interpretationown data

    Overall, the data provide a reasonably large sample of observations on which to examine cohort differences in change.

    “Overall, the data provide a reasonably large sample of observations on which to examine cohort differences in change.”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    Later born cohorts have greater cognitive reserve, which may mitigate nearness-to-death effects particularly for acculturated abilities.

    “Given that verbal meaning is the PMA that is conceptually closest to the crystallized ability domain (Schaie et al., 2005), our results are also consistent with the notion that later born cohorts have greater cognitive reserve, which may mitigate nearness-to-death effects particularly for acculturated abilities (see also Stern et al., 1999).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Schaie et al., 2005

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

    • cites Stern et al., 1999 source

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    The precautionary steps taken to adjust for selectivity included age at assessment, age at death, and presence of circulatory diseases and cancer as covariates.

    “The precautionary steps we took to adjust for this possibility were to include age at assessment, age at death, and the presence of circulatory diseases and cancer as covariates into our models.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductnone given

    The inclusion of age at study entry, age at death, education, circulatory disease, cancer, and gender served to covary for possible confounds and were attrition-informative variables.

    “We note that the inclusion of age at study entry, age at death, education, circulatory disease, cancer, and gender into our models served to covary for possible confounds and were also attrition-informative variables.”
    Quote in the paperSubstantial claim

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

    Interpretationreasoning

    The later born cohort likely was still somewhat favored regarding the research questions.

    “note that the later born cohort likely was still somewhat favored regarding our research questions.”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    Cohort differences may also have existed in the treatment of terminal illnesses such as cancer, possible cognitive side effects of such treatments, the length of terminal illness and the age at which cognitive pathologies and dementia set in, or place of death.

    “As a consequence, cohort differences may also have existed in the treatment of terminal illnesses such as cancer (e.g., chemotherapy, beta blockers), possible cognitive side effects of such treatments, the length of terminal illness and the age at which cognitive pathologies and dementia set in, or place of death (home vs. hospital vs. nursing home).”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    Once terminal decline has set in, the amount of decline may be steeper among those born later.

    “However, once terminal decline has set in, the amount of decline may then be steeper among those born later (e.g., because they have more to lose).”
    Quote in the paperNot a substantial claim

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

    Study design and conductreasoning

    The 7-year intervals between measurement occasions may be too long to fully capture any 'accelerations' in how the mortality-related processes unfold.

    “Furthermore, the 7-year intervals between measurement occasions may be too long to fully capture any “accelerations” in how the mortality-related processes unfold.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    Positive secular trends that may have existed at an earlier point in life may be offset or even reversed.

    “In contrast, positive secular trends that may have existed at an earlier point in life may be offset or even reversed.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    Cardiovascular and major circulatory diseases have shown persistent declines over the past 30 years, particularly among men.

    “Cardiovascular and major circulatory diseases, such as heart disease and stroke, have shown persistent declines over the past 30 years, particularly among men”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Aldwin, Spiro, & Park, 2006

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

    • cites Manton et al., 2008 source

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

    Study design and conductreasoning

    The suitability of the quadratic change models for the study of terminal decline might be viewed as a suboptimal approximation of the terminal decline phenomena.

    “Finally, the suitability of the quadratic change models for the study of terminal decline might also be viewed as a suboptimal approximation of the terminal decline phenomena—which imply discrete shifts in the rate of decline, a phase transition—rather than as “continuous” (and invariant in time) changes in the rate of change.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    Previously higher levels of functioning are not maintained during manufactured survival.

    “One way to interpret our results is that previously higher levels of functioning are not maintained during manufactured survival.”
    Quote in the paperSubstantial claim

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

    Interpretationreasoning

    Such a scenario would even be consistent with the pattern found in our single-phase models.

    “Such a scenario would even be consistent with the pattern found in our single-phase models.”
    Quote in the paperNot a substantial claim

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

    Premisenone given

    Major legislative changes in the first 20 years of the 20th century contributed to cohort differences in educational attainment.

    “major legislative changes in the first 20 years of the 20th century (e.g., compulsory school attendance, extended length of the school year) contributed to cohort differences in educational attainment.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Cohorts not only differ in quantitative aspects of education but often also have experienced qualitatively different educational systems.

    “However, cohorts not only differ in such quantitative aspects of education but often also have experienced qualitatively different educational systems (e.g., shift from rote learning to more participatory strategies, such as discovery learning; see Emirbayer, 1992; Schaie, 2008) for which we unfortunately have not had any direct data.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Emirbayer, 1992 source
    • cites Schaie, 2008

      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).

    Interpretationreasoning

    Provided sufficient technological support, members of the later born cohort may have survived impairments or diseases that have resulted in death among members of earlier born cohorts.

    “Provided sufficient technological support, members of the later born cohort may have survived impairments or diseases that have resulted in death among members of earlier born cohorts.”
    Quote in the paperNot a substantial claim

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

    Study design and conductcitation

    All cognitive tests showed high test-retest reliabilities over 1 month (N = 705; r ≥ .78).

    “All tests showed high test–retest reliabilities over 1 month (based on N = 705; r ≥ .78; see Schaie, 2005).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Schaie, 2005 source

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

    Study design and conductcitation

    Interrater reliabilities for medical data were high (Cronbach's α > .90).

    “Interrater reliabilities were high (Cronbach’s α > .90; for details, see Bosworth & Schaie, 1997; Hertzog, Schaie, & Gribbin, 1978).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Bosworth & Schaie, 1997 source
    • cites Hertzog, Schaie, & Gribbin, 1978 source

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

    Interpretationreasoning

    For the later born cohort, morbidity-related cognitive declines may not set in until diseases become severe, probably because of advances in health care.

    “For the later born cohort, in contrast, morbidity-related cognitive declines may not set in until diseases become severe, probably because of advances in health care.”
    Quote in the paperNot a substantial claim
57 of 57

  • The authors state this as an assumption.

    Incomplete longitudinal data were missing at random.

    “under the assumption that incomplete data were missing at random (Little & Rubin, 1987; McArdle, 1994).”

  • The authors state this as an assumption.

    Period or time-of-measurement effects can be ignored.

    “Making the simplifying assumption of ignoring period or time-of-measurement effects (for discussion, see Schaie & Herzog, 1983)”
2 of 2

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.

  • ConsistentF(1, 5346) = 122.7reported p < .001 · recomputed p < .001

    “F(1, 5346) = 122.70, p < .001”

  • ConsistentF(1, 2509) = 7.56reported p < .01 · recomputed p = .006

    “F(1, 2509) = 7.56, p < .01”

2 of 2

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.

  • Birth-year range changes from 1886 to 1883

    Minor

    The methods define the earliest included birth year as 1886, but the discussion describes the analyzed individuals as born as early as 1883.

  • Number ability is said to lack positive cohort effects despite a positive rate effect

    Minor

    The discussion says number ability showed no evidence of positive cohort effects. The results report a significant positive cohort difference in its rate of cognitive aging, favoring the later-born cohort.

2 of 2

Cites

Flagged first, then by citations

Research works printed but not linked: 5

  1. Elder GH Jr. Children of the Great Depression: Social change in life experience 1974 University of Chicago Press Chicago, IL
  2. Flynn JR What is intelligence? 2007 Cambridge University Press Cambridge, England
  3. Kleemeier RW Intellectual changes in the senium Proceedings of the American Statistical Association 1962 1 290 295
  4. Ram N Gerstorf D Fauth B Zarit SH Malmberg B Aging, disablement, and dying: Three time metrics for charting late-life change Research in Human Development 2010 7 27 44 PMC3482431 23112747
  5. Schaie KW Charness N Impact of technology on the aging individual 2003 Springer New York, NY

Cited by

Sorted by citations

Related

Authors
Gerstorf, D., Ram, N., Hoppmann, C., Willis, S. L., & Schaie, K. W.
Affiliations
  • Pennsylvania State University (US)
  • University of British Columbia (CA)
  • University of Washington (US)
ORCID
Venue
Developmental Psychology
Publisher
American Psychological Association (APA)
Published
2011
Volume
47
Issue
4
Pages
1026-1041
ISSN
  • 0012-1649 (ISSN-L)
  • 1939-0599
DOI
10.1037/a0023426
PMC
PMC3134559
OpenAlex
W2096560961
Semantic Scholar
2ab94d5387d2bb601150eab791cf97bb782fede8
Cited by
154
References
84
Citations by year
2026: 7 · 2025: 9 · 2024: 6 · 2023: 8 · 2022: 13 · 2021: 12 · 2020: 9 · 2019: 14 · 2018: 16 · 2017: 15 · 2016: 14 · 2015: 9 · 2014: 10 · 2013: 7 · 2012: 5
FWCI
9.07
Type
journal article
Language
en
Open access
Locations
  • Developmental Psychology (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Funders
National Institute on Aging (RC1-AG035645, R21-AG032379, R21-AG033109)
Topics
  • Social Sciences › Psychology › Neuropsychology and Physiological Psychology › Aging and Gerontology Research
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Cognitive Abilities and Testing
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
Keywords
cohort differences, cognitive aging, terminal decline, Seattle Longitudinal Study, primary mental abilities, secular trends, life expectancy, older adults, birth cohort
MeSH terms
Age Factors, Aged, Aged, 80 and over, Aging, Cognition, Cognition Disorders, Female, Humans, Life Expectancy, Longitudinal Studies, Male, Middle Aged, Neuropsychological Tests, Spatial Behavior, Time Factors, Washington, Cohort Studies

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 2026-11-03.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-11-03.

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.

What counts as a claim ›How we measure confidence ›How we check this ›

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