"Resolving the IQ paradox: Heterosis as a cause of the Flynn effect and other trends": Correction to Mingroni (2007).

Mingroni, Michael A.

doi:10.1037/0033-295x.114.4.1104

Cited by 5 publications

(4 citation statements)

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“…It finally needs to be noted that Mingroni himself also appears to have found evidence directly disconfirming the heterosis hypothesis, which was presented at the 2002 International Society for Intelligence Research conference (see Mingroni, 2002). In this study, he examined the effects of intergenerational differences in genetic heterozygosity on IQ amongst a sample of 92 parent–child trios.…”

Section: Dissecting the Flynn Effectmentioning

confidence: 97%

“…In this study, he examined the effects of intergenerational differences in genetic heterozygosity on IQ amongst a sample of 92 parent–child trios. The heterosis hypothesis requires that the higher IQ amongst the children should be positively associated with higher levels of heterozygosity; however, the opposite was found, namely, that the parents exhibited higher levels of heterozygosity than the children despite the children exhibiting higher levels of IQ, as measured by SAT scores (Mingroni, 2002). An implication of this finding is that secular gains on IQ tests are wholly independent of intergenerational differences in the degree of heterozygosity, thus indicating that the Flynn effect cannot be genetic in origin.…”

Section: Dissecting the Flynn Effectmentioning

confidence: 99%

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Heterosis doesn't cause the Flynn effect: A critical examination of Mingroni (2007).

Woodley¹

2011

Psychological Review

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Mingroni (2007) proposed that heterosis or hybrid vigor may be the principal driver of the Flynn effect--the tendency for IQ scores to increase at a rate of approximately 3 points per decade. This model was presented as a resolution to the IQ paradox--the observation that IQ scores have been increasing despite their high adult heritability--on the basis that substantial changes in IQ can only be accounted for by changes in underlying genetic factors. It is here argued that this model is predicated upon a misconception of the Flynn effect, which is most pronounced on the least g-loaded components of cognitive ability tests and is uncorrelated with genetic effects such as inbreeding depression scores (which are correlated with the g loadings of tests). Evidence supportive of the recently proposed life history model of the Flynn effect is presented. In the discussion, other theoretical objections to the heterosis model are also considered. On this basis, it is concluded that the Flynn effect is strongly entwined with developmental status and that heterosis cannot be its principal cause.

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Section: Dissecting the Flynn Effectmentioning

confidence: 97%

Section: Dissecting the Flynn Effectmentioning

confidence: 99%

Heterosis doesn't cause the Flynn effect: A critical examination of Mingroni (2007).

Woodley¹

2011

Psychological Review

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“…Environmental factors have frequently been proposed as the main cause of the positive secular trends in human characteristics; this includes the improved quality of nutrition, sanitation, hygiene and health care, the decreased rate of infections and other diseases, the higher value and better structure of educational systems, the reduced size of families and higher standard of child rearing, the increased overall complexity of environments, and ultimately, the economic advance of societies ( 6 ). In contrast to these environmental explanatory factors, increases in genetic diversity and consequently genetic advantages resulting from demographic trends towards more random mating in recent societies were also proposed ( 7 ). However, a single explanation does, likely, not suffice to fully account for the positive secular trends in populations’ traits but a combination of multiple aspects that may vary across domains may be relevant ( 3 ).…”

Section: Introductionmentioning

confidence: 99%

“…Mingroni was among the first who did not only focus on single secular trends, but also explored secular changes in multiple variables such as height, head circumference, intelligence, myopia, asthma, autism and others at the same time ( 7 , 11 ). In fact, the concurrent investigation of secular changes in multiple traits may contribute to identifying the explanatory processes underlying them.…”

Section: Introductionmentioning

confidence: 99%

Secular trends in physical growth, biological maturation, and intelligence in children and adolescents born between 1978 and 1993

Eichelberger,

Chaouch,

Rousson

et al. 2024

Front. Public Health

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IntroductionHuman physical growth, biological maturation, and intelligence have been documented as increasing for over 100 years. Comparing the timing of secular trends in these characteristics could provide insight into what underlies them. However, they have not been examined in parallel in the same cohort during different developmental phases. Thus, the aim of this study was to examine secular trends in body height, weight, and head circumference, biological maturation, and intelligence by assessing these traits concurrently at four points during development: the ages of 4, 9, 14, and 18 years.MethodsData derived from growth measures, bone age as an indicator of biological maturation, and full-scale intelligence tests were drawn from 236 participants of the Zurich Longitudinal Studies born between 1978 and 1993. In addition, birth weight was analyzed as an indicator of prenatal conditions.ResultsSecular trends for height and weight at 4 years were positive (0.35 SD increase per decade for height and an insignificant 0.27 SD increase per decade for weight) and remained similar at 9 and 14 years (height: 0.46 SD and 0.38 SD increase per decade; weight: 0.51 SD and 0.51 SD increase per decade, respectively) as well as for weight at age 18 years (0.36 SD increase per decade). In contrast, the secular trend in height was no longer evident at age 18 years (0.09 SD increase per decade). Secular trends for biological maturation at 14 years were similar to those of height and weight (0.54 SD increase per decade). At 18 years, the trend was non-significant (0.38 SD increase per decade). For intelligence, a positive secular trend was found at 4 years (0.54 SD increase per decade). In contrast, negative secular trends were observed at 9 years (0.54 SD decrease per decade) and 14 years (0.60 SD decrease per decade). No secular trend was observed at any of the four ages for head circumference (0.01, 0.24, 0.17, and − 0.04 SD increase per decade, respectively) and birth weight (0.01 SD decrease per decade).DiscussionThe different patterns of changes in physical growth, biological maturation, and intelligence between 1978 and 1993 indicate that distinct mechanisms underlie these secular trends.

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What has caused the Flynn effect? Secular increases in the Development Quotients of infants

Lynn

2009

Intelligence

104

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"Resolving the IQ paradox: Heterosis as a cause of the Flynn effect and other trends": Correction to Mingroni (2007).

Cited by 5 publications

References 0 publications

Heterosis doesn't cause the Flynn effect: A critical examination of Mingroni (2007).

Heterosis doesn't cause the Flynn effect: A critical examination of Mingroni (2007).

Secular trends in physical growth, biological maturation, and intelligence in children and adolescents born between 1978 and 1993

What has caused the Flynn effect? Secular increases in the Development Quotients of infants

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