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An Historical Framework for Cohort Differences in Intelligence
Open accessAbstract
This article reviews key issues regarding the controversy on the direction and magnitude of cohort differences in intelligence. Data from the Seattle Longitudinal Study (SLS) illustrate why differences must be studied across multiple cohorts and multiple chronological ages. Differential cohort patterns for multiple dimensions of intelligence are described. A conceptual framework is suggested for the identification of historical influences important for developmental study of cohort differences.
Overview
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TL;DR
This review uses Seattle Longitudinal Study (SLS) data to argue that cohort differences in intelligence are more complex than the Flynn effect: gains occur for some abilities and historical periods but not others, and must be studied across multiple cohorts and ages. It proposes a Bronfenbrenner-derived historical framework emphasizing education, work, and macrosocial events as mechanisms.
Key findings
- SLS data broadly support the Flynn effect for some abilities: inductive reasoning increased by approximately ½ SD from birth cohort 1931 to 1952, while number ability showed a negative trend and verbal and number ability differences were more modest.
- Across 13 cohorts (median birth years 1889–1973), both positive and negative cohort trends appeared: verbal meaning and inductive reasoning showed substantial positive gains, with cohort differences (1889–1952) for verbal ability equivalent to inductive reasoning until the 1959 cohort, when the verbal gradient began to decline.
- Number ability rose up to about the 1910 cohort, then plateaued and shifted negatively, with the 1924 cohort exceeding both earlier and later cohorts; word fluency showed a concave pattern, negative until the 1938 cohort and improving thereafter.
- Educational attainment increased by an average of 5½ years over the period studied, with a greater increase of 1 year for men; average school-year length was 140 days for Cohort 2 versus 170 and 180 days for Cohorts 6 and 10, and daily attendance was about 65% versus 85% and 90%, respectively.
Methods
- Review and conceptual article using SLS data; SLS includes seven cross-sectional data collections from 1956 to 1998 in 7-year intervals, covering ages 22–70 initially and later 22–84, with thirteen 7-year birth cohorts (median birth years 1889–1973).
- Cohort differences were estimated by comparing successive cohorts over common ages, using average unweighted mean differences; cumulative cohort differences were computed over an 84-year time frame, and trajectories were illustrated for three cohorts (Cohorts 2, 6, and 10) using successive independent random samples.
- The conceptual framework adapts Bronfenbrenner’s ChronoSystem, ExoSystem, and MesoSystem across developmental phases to identify historical influences on cohort differences.
Limitations
- Stated: the SLS analysis is restricted in cross-national comparisons and focuses specifically on historical contexts affecting the United States; broader political and cultural changes are beyond the article’s scope.
- Evident: the authors note that estimated cohort effects are confounded with period effects, and the historical mechanisms discussed are illustrative rather than causally tested.
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Claims the paper makes
42 No basis given · 38 Own interpretation · 32 No full text of the sources · 15 Own result · 14 Sources not found · 11 Not checked yet · 5 Own method
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In the paper
“Although the SLS sample has the advantage in level of education, the magnitude of total cohort gain in years of education found in the SLS (birth cohorts 1889–1973) is quite comparable to that reported for national representative samples.”
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“The magnitude of cohort gain appears to have been greater in the early 1900s than that cited for the post-World War II cohorts.”
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In the paper
“In addition, positive, negative, and curvilinear cohort trends have been observed.”
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In the paper
“With respect to the purest measures of both fluid and crystallized intelligence, the trends in the SLS data broadly support the Flynn effect.”
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“Moreover, although considerable attention has been given to the massive IQ gains for the post-World War II 1950 cohorts, the SLS data suggest that the magnitude of cohort gains (at least for verbal meaning and inductive reasoning) were much greater for the cohorts born in the early 1900s than for the cohorts cited in the Flynn effect.”
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In the paper
“Both fluid and crystallized abilities have exhibited significant positive gains, particularly in the early 1900 birth cohorts.”
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In the paper
“Indeed inductive reasoning shows the strongest positive linear trend of any ability examined within the SLS study for these cohorts.”
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“There is an increase on the order of approximately ½ SD for fluid intelligence as measured by inductive reasoning from birth cohort 1931 to birth cohort 1952.”
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“When five distinct cognitive abilities are examined across 13 rather than 4 cohorts, it becomes clear that there are both positive and negative cohort trends.”
boostedcorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“In contrast, cohort differences over the same cohorts are more modest for the two crystallized abilities of verbal and number ability and even for the fluid ability of spatial orientation.”
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- It may state two separate claims as one. 49
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In the paper
“In fact, number ability exhibits a negative trend, which, as we show, is much more pronounced when examined across a broader range of cohorts.”
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“Indeed, the cohort differences (1889–1952) for verbal ability are of equivalent magnitude to that for inductive reasoning until the 1959 cohort, which is when the gradient began to decline for verbal meaning.”
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“In contrast to the conclusions that would be drawn from data cited for the Flynn effect, these data indicate that there are systematic and substantial positive advances in cohort level for both crystallized ability (verbal meaning) and fluid abilities (spatial orientation and inductive reasoning).”
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In the paper
“For example, over the Baby Boomer cohorts (1945–1966), there has been a positive linear trend for inductive reasoning, a negative trend for number, and a plateau for verbal ability.”
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“Word fluency, by contrast, shows a concave pattern. A negative cohort trend prevails until the 1938 cohort, but improvement occurs for subsequent cohorts.”
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“A similar trend is shown in the SLS data in Figure 3.”
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“Far more substantial differences in level are found in old age between Cohorts 2 and 6, but now there is also a substantial difference in slope, particularly for verbal meaning, favoring the later born cohort.”
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In the paper
“For this ability, then, earlier cohorts have a slight advantage over the later born ones; but beginning with the cohort born in 1945, there are also successive positive cohort differences for this ability.”
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“The trajectories for the three sample cohorts, first of all, reflect the overall cohort differences in level, but they also demonstrate that the trajectories differ by ability as well as by life stage.”
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In the paper
“The 1924 cohort exceed both earlier and later born cohorts; the youngest cohorts are, therefore, currently at a disadvantage when compared with the older cohorts.”
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In the paper
“Thus, in midlife, there is little difference between Cohorts 6 and 10 on verbal meaning but a modest systematic gain for Cohort 10 on inductive reasoning.”
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In the paper
“And, indeed, our own studies show marked increase in educational attainment for subsequent cohorts, resulting in an average increase of 5½ years over the period studied, with a greater increase of 1 year for men (see Figure 3).”
plaindirect- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Number ability shows positive cohort differences up to about the 1910 cohort. But then there is a plateau followed by a negative shift that indicates a successive lowering of performance level.”
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In the paper
“There is strong suggestive evidence that current cohorts may be peaking at later ages or maintaining their peak level of functioning until a later chronological age (Schaie, 2005).”
What the sources say
- Not checked — no full text of the sourcecites Schaie, 2005 source
hedgedconditional- Asserted: passes — The authors put it forward as true.
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In the paper
“Perhaps the largest difference between our Cohorts 2 and 6 is the dramatic increase in educational attainment, which is accompanied by marked cohort differences at comparable ages for both verbal ability and inductive reasoning skills.”
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In the paper
“We also noted dramatic changes in the level of occupational pursuits, associated with structural changes in the labor market, but also requiring acquisition of educational skills commonly associated with upward socioeconomic mobility.”
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In the paper
“We pointed out, however, that cohort differences in intelligence were even more dramatic for cohorts born prior to those studied by Flynn, but they have diminished in subsequent cohorts.”
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In the paper
“Another major change for the latter cohort is the increase of women in the workforce, accompanied by an increase in their educational levels (now similar to their male peers).”
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“Also, these transitions are usually defined by a circumscribed relatively brief time period during which they occur.”
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In the paper
“Two types of transitions have been distinguished in the psychological and sociological literatures (Baltes, 1979; Riley et al., 1972): normative (school entry, puberty, work entry, marriage, child bearing, and retirement) and nonnormative (death or severe illness, divorce, and winning the lottery).”
What the sources say
- Not checked — no full text of the sourcecites Baltes, 1979
- Not matchedcites Riley et al., 1972
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“The cohort effects estimated in this manner will, of course, be confounded with period effects, but if a series of cohort differences are computed across the same time period, each estimate will be equally affected.”
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In the paper
“The data reported by Flynn and others are insufficient to address this question given the limited range of cohorts examined.”
What the sources say
- Not checked — no full text of the sourcecites Flynn, 1987 source
plain- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“On the other hand, sampling with replacement may be problematic if the population frame changes over time.”
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In the paper
“Hauser and Featherman (1976) noted that intergenerational differences in schooling peaked among men born shortly after World War I and that a deceleration has occurred across more recent cohorts.”
What the sources say
- Not checked — no full text of the sourcecites Hauser and Featherman (1976) source
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“The negative cohort effects on verbal ability reported by Alwin (1991) may be due to confusing cohort effects with aging, treating the relationship between age and verbal ability as linear rather than curvilinear (Wilson & Gove, 1999).”
What the sources say
hedgedconditional- Asserted: passes — The authors put it forward as true.
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In the paper
“The impact of such historical or sociocultural life-course events on individual development has been an important focus of the work of social psychologists such as Elder (1974), Stewart (2003), and, to some extent, Helson and Moane (1987).”
What the sources say
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“Hence, performance on psychometric markers of fluid ability can be improved through educational procedures, although their basic information-processing components might not be affected.”
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“there is a large body of literature indicating that fluid abilities (as measured by psychometric tests) as well as crystallized abilities are significantly impacted by environmental influences.”
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The issue of the lack of comparable chronological ages across cohorts is, in particular, a critical one in evaluating cohort differences and a criterion that has been seriously abused in prior studies.”
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“That is, the same test items may not mark the construct equally well in all cohorts; content becomes obsolete.”
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In the paper
“As Kahn and Antonucci’s (1980) model of convoys of social support suggest, the significant others in the individual’s life would be expected to change across the life course, progressing from parents to spouses and extended family, friends, and colleagues.”
What the sources say
- Not checked — no full text of the sourcecites Kahn and Antonucci’s (1980)
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In the paper
“As research in the SLS and other cohort-sequential studies have shown, each of these criteria is problematic.”
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“That is, the direct comparison of different cohorts at one point in time confounds cohort with age effects, whereas comparison of cohorts at the same age but different points in time confound cohort and period effects (cf. Ryder, 1965; Schaie, 1965; Wilson & Gove, 1999).”
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“These transitions are usually specific to a particular life domain (e.g., marriage or work) although there may be spillover to other domains.”
hedged- Asserted: passes — The authors put it forward as true.
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Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We then use Seattle Longitudinal Study (SLS) data to illustrate how the recent debate has been too narrow due to the limited range of birth cohorts examined and because cohort differences are often studied nondevelopmentally by considering only a single chronological age.”
plain- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Also, the difficulty level of specific test items may shift markedly across cohorts and time.”
hedgedconditional- Asserted: passes — The authors put it forward as true.
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In the paper
“The appropriate data to be used for comparison of the trajectories of different cohort come from successive independent random samples of each of the three cohorts. These data are thus unbiased with respect to attrition and/or retest effects.”
plain- Asserted: passes — The authors put it forward as true.
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- Based: unclear — It is unclear why the paper says it holds.
It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Given the seven waves of the SLS, this means that cohort differences for those cohorts entering the study at an early stage can be compared at as many as six different ages, whereas the most recently entered cohort can be compared only at the one age at which it was measured.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“The average length of the school year for Cohort 2 was 140 days compared with 170 days and 180 days for Cohorts 6 and 10, respectively.”
What the sources say
- Not matchedcites U.S. Department of Education, National Center for Education Statistics, 2002
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Not matched
In the paper
“State legislation on the length of the school year and compulsory school attendance passed during the same period impacted not only the proportion of children in school but the intensity of the educational experience.”
What the sources say
- Not matchedcites U.S. Department of Education, National Center for Education Statistics, 2002
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Not matched
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The declining influence of social background reflects changes both in the variance of the social background characteristics and in their effects on schooling.”
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Both father’s education and occupation status have increased across cohorts, whereas the number of siblings has decreased.”
What the sources say
- Not checked — no full text of the sourcecites Hauser & Featherman, 1976 source
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“A final caution: As Riley (1972) taught us, changes in the characteristics of populations will, in turn, change the social structures that have produced these changes; hence, we experience an interactive process that requires continuous monitoring and study.”
What the sources say
- Not matchedcites Riley (1972)
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: fails — It may be too vague to check against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it. It may state two separate claims as one.
- Not matched
In the paper
“Sampson and Laub (1996) reported that GI Bill training as well as in-service schooling enhanced subsequent occupational status, job stability, and economic well being, independent of childhood differences and socioeconomic background.”
What the sources say
- Not checked — no full text of the sourcecites Sampson and Laub (1996) source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Almost 50% of all veterans of World War II and the Korean War used the benefits for education and training, and 82% of those veterans who had attended college before the war made use of GI benefits to continue their education.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“There have been a number of studies examining key social background variables associated with final educational attainment (cf. Alwin & Thornton, 1984).”
What the sources say
- Not checked — no full text of the sourcecites Alwin & Thornton, 1984 source
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The SLS’s Cohort 6 would have been particularly affected by the GI Bill associated with World War II.”
hedgedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“However, despite this restriction, the data, because of their extensive comparative and longitudinal findings within one study, have far-reaching implications for interpretations of the so-called Flynn effect.”
boostedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: fails — It may be too vague to check against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may be too vague to check against evidence.
In the paper
“On average a farm background cost men 1 full year of schooling, and Southern birth cost .4 to .8 years of schooling.”
What the sources say
- Not checked — no full text of the sourcecites Hauser & Featherman, 1976 source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“The variables of being raised on a farm and being born in the South also had a substantial effect.”
What the sources say
- Not checked — no full text of the sourcecites Hauser & Featherman, 1976 source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Approximately 33% of veterans whose college work was interrupted by military service finished college or went on to graduate or professional school.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Among the social background variables studied were father’s education, father’s occupation, number of siblings, broken family, farm background, and Southern birth—many of these variables clearly pertain to the environment of the father as well as the subject of interest.”
What the sources say
- Not checked — no full text of the sourcecites Hauser & Featherman, 1976 source
boosted- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Almost 50% of all veterans of World War II and the Korean War used the benefits for education and training, and 82% of those veterans who had attended college before the war made use of GI benefits to continue their education.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Thus, Cohort 6 could represent the children of Cohort 2; likewise, Cohort 10 could represent children of Cohort 6.”
hedgedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“A marked shift in educational philosophy between Cohort 2 and Cohort 6 was the Progressive movement in education, which peaked in the 1920s and whose most noted proponent was John Dewey (Emirbayer, 1992).”
What the sources say
- Not checked — no full text of the sourcecites Emirbayer, 1992 source
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“First, given the existing psychometric ability measures, it is unlikely that fluid abilities would provide stronger tests of cohort effects than those provided by crystallized measures.”
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper may give no reason why it holds.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The benefits of the GI Bill were larger for younger veterans and for those who had some evidence of delinquency in military service records.”
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: unclear — It is unclear why the paper says it holds.
It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“On the one hand, due to the increased number of pupils resulting from child labor laws and compulsory school attendance, the educational practices of standardized testing and tracking of students was introduced.”
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Of relevance for this article is the fact that a number of these social background variables pertain to the parent’s characteristics and thus would be considered in our framework in ExoSystem models.”
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“In the child literature, the parents’ work environment has been shown to impact child-rearing practices (Kohn & Schooler, 1983), occupational aspirations of adolescents (Mortimer & Kumka, 1982), and curricular activities (Morgan, Alwin, & Griffin, 1979).”
What the sources say
- Not matchedcites Kohn & Schooler, 1983
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
- Not matched
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“A major provision of the law involving a $15 million grant was the provision of funds to identify talented students and encourage them to pursue higher education.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Advances in cognitive science would suggest, in any event, that a test of cohort differences in fluid abilities should be conducted using measures of more basic levels of information processing.”
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: fails — It may be too vague to check against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. It may be too vague to check against evidence. The paper may give no reason why it holds.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Its focus is specific to historical contexts affecting the United States.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“The analysis of cohort effects in the SLS, although rich in within-nation longitudinal and cohort-comparative sampling, is, of course, restricted in the scope of cross-national comparisons.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“In the 1957–1958 term alone, congress proposed over 80 laws to establish programs that would seek out bright students and provide them with financial support for schooling.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Yet, changes in rates of aging in intellectual performance have serious societal consequences for the nature of the workforce, the stability of pension systems, and the nature of the health care system required to serve a growing elderly population that differs markedly from earlier cohorts.”
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: fails — It may be too vague to check against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. It may be too vague to check against evidence. The paper may give no reason why it holds.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The national panic generated by this event resulted in Congress passing a federal-aid-to-education bill, known as The National Defense Education Act of 1958.”
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Our analysis of the historical influences on education suggests that cohort differences in intellectual abilities are shaped largely by changes in educational attainment and educational process and by changes in the labor market that are shaped by sociopolitical developments.”
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“One of the most prominent examples are the postwar rehabilitation programs for veterans, known as the GI Bills (Nam, 1964; Sampson & Laub, 1996).”
What the sources say
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The Progressive movement also involved the introduction of the kindergarten, manual and vocational education, and evening classes for adults.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In addition, primarily as a consequence of the secular rise in educational attainment, successive cohorts of young persons have distributions of social background variables that are gradually becoming more favorable to high levels of schools, as evidenced by increases in parent’s educational and their occupational levels.”
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“These background variables account for 30% to 37% of the variance in educational attainment of males of various cohorts.”
What the sources say
- Not checked — no full text of the sourcecites Hauser & Featherman, 1976 source
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“First, we note that the three illustrative SLS cohorts (Cohorts 2, 6, and 10) discussed herein represent three successive generations, separated by approximately 30 years.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper may give no reason why it holds.
In the paper
“Similarly, in 1956 25% of all male college students were veterans of the Korean War (Nam, 1964).”
What the sources say
- Not checked — no full text of the sourcecites Nam, 1964 source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“In the child literature, the parents’ work environment has been shown to impact child-rearing practices (Kohn & Schooler, 1983), occupational aspirations of adolescents (Mortimer & Kumka, 1982), and curricular activities (Morgan, Alwin, & Griffin, 1979).”
What the sources say
- Not checked — no full text of the sourcecites Mortimer & Kumka, 1982 source
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“Further educational training was provided through GI Bills for veterans of World War II, the Korean War, and the Vietnam War.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper may give no reason why it holds.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“For veterans who had just completed high school or had barely started college, 20% went on to get a college degree and a larger proportion took at least some college courses.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“The mean level of fathers’ education had increased from about 7 years to almost 11 years.”
What the sources say
- Not checked — no full text of the sourcecites Hauser & Featherman, 1976 source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Each of the following variables accounted for about 25% of a year gain in level of educational attainment: 1 year of father’s schooling, 10 points of father’s occupation status, and additional sibling.”
What the sources say
- Not checked — no full text of the sourcecites Hauser & Featherman, 1976 source
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“In 1957 the Soviet Union launched Sputnik.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
In the paper
“Standardized testing was viewed as a more scientific way to determine children’s likely occupational attainment and to allocate them into different educational channels (Ackerman, 1995).”
What the sources say
- Not checked — no full text of the sourcecites Ackerman, 1995 source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
None of the sources cited for this claim have been checked yet.
In the paper
“Hauser and Featherman (1976) utilized data from the OCG surveys (Blau & Duncan, 1967) to examine key social background variables associated with educational attainment of male birth cohorts from 1897 to 1951.”
What the sources say
- Not checked — no full text of the sourcecites Hauser & Featherman, 1976 source
- Not matchedcites Blau & Duncan, 1967
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For example, the discussion of the effect of the GI Bill on educational attainment of Cohort 6 could be construed as an ExoSystem environment for Cohort 10.”
hedgedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Second, the notion that one should measure cohort differences in mature persons implies that ages of peak performance remain constant across cohorts (not true) or, when samples ranging widely in age are utilized, assumes that there are no adult age changes.”
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper may give no reason why it holds. It may state two separate claims as one.
In the paper
“In the child literature, the parents’ work environment has been shown to impact child-rearing practices (Kohn & Schooler, 1983), occupational aspirations of adolescents (Mortimer & Kumka, 1982), and curricular activities (Morgan, Alwin, & Griffin, 1979).”
What the sources say
- Not checked — no full text of the sourcecites Morgan, Alwin, & Griffin, 1979 source
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“The goal of the movement was development of a demographic character equipped for responsible citizenship.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Thus, the ChronoSystem environments that we have discussed for a given cohort could be considered as the ExoSystem environment for a preceding cohort.”
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Daily attendance was approximately 65% for Cohort 2 compared with 85% and 90% for Cohorts 6 and 10, respectively (U.S. Department of Education, National Center for Education Statistics, 2002).”
What the sources say
- Not matchedcites U.S. Department of Education, National Center for Education Statistics, 2002
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Not matched
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“On the other hand, the Progressive movement also advocated movement away from teacher-directed lecture and rote recitation to increased student–teacher interaction, group exercises, and critical reflection.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“For example, the father’s educational or occupational status experienced as a young adult and occurring in a particular historical period have been studied as influences on subsequent intellectual functioning of the offspring (Hauser & Featherman, 1976).”
What the sources say
- Not checked — no full text of the sourcecites Hauser & Featherman, 1976 source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
In the paper
“Father’s education was relatively more important than any other background variable in all groups examined.”
What the sources say
- Not checked — no full text of the sourcecites Hauser & Featherman, 1976 source
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“The Progressive movement advocated what today seem to be contradictory initiatives (Emirbayer, 1992).”
What the sources say
- Not checked — no full text of the sourcecites Emirbayer, 1992 source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
The authors state this as an assumption.
Cohort differences should persist across wide age ranges.
“It also seems appropriate to assume that cohort differences should persist across wide age ranges, whereas period effects are likely to show their impact differentially by life stage.”
The authors state this as an assumption.
Period effects are likely to show their impact differentially by life stage.
“It also seems appropriate to assume that cohort differences should persist across wide age ranges, whereas period effects are likely to show their impact differentially by life stage.”
The authors state this as an assumption.
Long-term cumulative events primarily impact individual development indirectly as mediated by environmental factors in the MesoSystem and ExoSystem and interact with the personal characteristics of the individual.
“It is assumed that long-term cumulative events primarily impact individual development indirectly as mediated by environmental factors in the MesoSystem and ExoSystem and interact with the personal characteristics (e.g., personality, attitudes, and life styles) of the individual who is a member of the cohort under investigation.”
The paper relies on this without support.
The relative impact of various environments (family, work, leisure/social, media/technology) varies across the life course and interacts with personal characteristics.
“The relative impact of these various environments is expected to vary across the life course and to interact with the personal characteristics of the individual.”
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.
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Abstract
“we estimated average cohort differences at all available ages between all adjacent cohort pairs from 1989 to 1973”
§ Abstract
“thirteen 7-year birth cohorts that have been followed over time, covering the range of median birth years from 1889 to 1973”
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Abstract
“We argued that historical influences of the ExoSystem (single domain and cumulative life-course transitions) exerts a dominant influence on individuals”
§ Abstract
“In Table 2, the ChronoSystem component includes both single-domain transitions and cumulative life course transitions and events;”
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Abstract
“These background variables account for 30% to 37% of the variance in educational attainment of males of various cohorts.”
§ Abstract
“In summary, the proportion of variance in educational attainment explained by the social background variables has declined from .35 to .28.”
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Abstract
“all other data collections (1970–1998) from ages 22 to 84.”
§ Abstract
“3 1903 1900–1906 53 60 67 74 81 88 95”
Citations
Cites
Ecology of the family as a context for human development: Research perspectives.
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The American Occupational Structure.
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The Cohort as a Concept in the Study of Social Change
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Massive IQ gains in 14 nations: What IQ tests really measure.
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The Cohort as a Concept in the Study of Social Change
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A general model for the study of developmental problems.
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Research works printed but not linked: 12
- Huston, A. C., Mistry, R. S., Bos, J. M., Low, E., & Shim, M. S. (in press). Well being of low-income adults in a period of historical changes in welfare and employment policies. In K. W. Schaie & G. H. Elder, Jr. (Eds.), Historical influences on lives and aging New York: Springer.
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- Schaie, K. W. (1990). Late life potential and cohort differences in mental abilities. In M. Perlmutter (Ed.), Late life potential (pp. 43–62). Washington, DC: Gerontological Society of America.
- Schaie, K. W. (1995). Quality of life and successful aging. In H. Klose (Ed.), Aging and modernization (pp. 69–85). Bonn, Germany: Friedrich Ebert Foundation.
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- Schaie, K. W. (2000). How does maintenance of intellectual competence contribute to quality of life and successful aging? In K. Manger (Ed.), Jenaer Universitätsreden [Jena University lectures] (Vol. 9, pp. 21–40). Jena, Germany: Hausdruckerei der FSU Jena [Friedrich-Schiller-University Press].
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Cited by
Sorted by citations
Life Span Theory in Developmental Psychology
Baltes, P. B., Lindenberger, U., & Staudinger, U. M. (2007) · Handbook of Child Psychology · doi:10.1002/9780470147658.chpsy0111 · Cited by 1,240
A two decade dementia incidence comparison from the Cognitive Function and Ageing Studies I and II
Matthews, F. E., Stephan, B. C. M., Robinson, L., Jagger, C., Barnes, L. E., Arthur, A., Brayne, C., Cognitive Function and Ageing Studies (CFAS) Collaboration, Comas-Herrera, A., Wittenberg, R., et al. (2016) · Nature Communications · doi:10.1038/ncomms11398 · Cited by 426
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Conceptual and Measurement Challenges in Research on Cognitive Reserve
Jones, R. N., Manly, J. J., Glymour, M. M., Rentz, D. M., Jefferson, A. L., & Stern, Y. (2011) · Journal of the International Neuropsychological Society · doi:10.1017/s1355617710001748 · Cited by 397
Loneliness across time and space
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Metadata
- Authors
- Schaie, K. W., Willis, S. L., & Pennak, S.
- Affiliations
- Pennsylvania State University (US)
- ORCID
- Willis, Sherry L.
- Venue
- Research in Human Development
- Publisher
- Informa UK Limited
- Published
- 2005-03
- Volume
- 2
- Issue
- 1-2
- Pages
- 43-67
- ISSN
- 1542-7609 (ISSN-L)
- 1542-7617
- PMC
- PMC1513180
- OpenAlex
- W2062957383
- Cited by
- 110
- References
- 49
- Citations by year
- 2026: 3 · 2025: 1 · 2024: 1 · 2023: 3 · 2022: 5 · 2021: 7 · 2020: 6 · 2019: 6 · 2018: 5 · 2017: 7 · 2016: 14 · 2015: 8 · 2014: 3 · 2013: 6 · 2012: 7
- FWCI
- 4.74
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Research in Human Development (publishedVersion)
- PubMed (publishedVersion)
- PubMed Central (acceptedVersion)
- Funders
- National Institute on Aging (R01AG008055)
- Topics
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Cognitive Abilities and Testing
- Social Sciences › Psychology › Developmental and Educational Psychology › Aging and Gerontology Research
- Social Sciences › Sociology and Political Science › Intergenerational and Educational Inequality Studies
- Keywords
- cohort differences, intelligence, historical influence, Seattle Longitudinal Study, intelligence development, conceptual framework
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
A language model drew the claims from the paper on 2026-11-03, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).
A second model labelled each claim on 2026-11-03 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).
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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