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

Lynn, Richard

doi:10.1016/j.intell.2008.07.008

Cited by 104 publications

(93 citation statements)

References 89 publications

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“…This is consistent with possible improvements in nutrition [39,40], educational practices, parental involvement, and the advantages of increased material wealth [41,42].…”

Section: Can Ph->e Transmission and Changes In Environmental Means Acsupporting

confidence: 79%

Can GE-Covariance Originating in Phenotype to Environment Transmission Account for the Flynn Effect?

et al. 2014

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Abstract:The Dickens and Flynn model of the Flynn effect (generational increases in mean IQ) assigns an important role to genotype-environment covariance (GE-cov). We quantify GE-cov in a longitudinal simplex model by modeling it as phenotype to environment (Ph->E) transmission in twin data. The model fits as well as the standard genetic simplex model, which assumes uncorrelated genetic and environmental influences. We use the results to explore numerically the possible role of GE-cov in amplifying increases in environmental means. Given the estimated Ph->E transmission parameters, GE-cov resulted in an amplification (in std units) of a factor 1.57 (full scale IQ) to 1.7 (performance IQ). The results lend credence to the role of GE-cov in the Flynn effect.

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“…This is consistent with possible improvements in nutrition [39,40], educational practices, parental involvement, and the advantages of increased material wealth [41,42].…”

Section: Can Ph->e Transmission and Changes In Environmental Means Acsupporting

confidence: 79%

Can GE-Covariance Originating in Phenotype to Environment Transmission Account for the Flynn Effect?

et al. 2014

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“…13 Thus, "modified Wessel criteria" are most often used, requiring the infant to have fussed/cried for more than three hours a day, on at least three days in any one week. 12,14,15 Although the modified Wessel criteria are widely used, firstly, normative studies in the general infant population are lacking 15 Secondly, considerable changes in infant care have occurred over the last 60 years since the Wessel criteria were published, 16,17 thus prevalence may be quite different than in the 1950s. Thirdly, while modified Wessel criteria have been used in different countries, the impact of cultural variations such as caregiving styles [18][19][20][21][22][23] and maternal soothing techniques 23,24 on the duration of infant fussing and crying may need to be taken into consideration.…”

Section: Introductionmentioning

confidence: 99%

Systematic Review and Meta-Analysis: Fussing and Crying Durations and Prevalence of Colic in Infants

Wolke

Bilgin

Samara

2017

The Journal of Pediatrics

188

168

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Objective: To determine the mean duration of fussing and crying and prevalence of colic using modified Wessel criteria in infants in the first 3 months of life. Is there a universal 6 week crying peak and what is the prevalence of colic according to age and country?Study Design: A systematic literature search was performed using the databases Medline, PsycINFO and Embase. The major outcome measure was mean total fuss/cry duration during 24 hours at 1-2 weeks (11 samples), 3-4 weeks (6 samples); 5-6 weeks (28 samples), 8-9 weeks (9 samples) and 10-12 weeks (12 samples). Results:Of 5687 articles reviewed, 28 diary studies (33 samples) were suitable for inclusion in meta-analysis. The studies included 8690 infants. No statistical evidence for a universal crying peak at 6 weeks across studies was found. Rather, the mean fuss/cry duration across studies was stable at around 117-133 minutes (SDs: 66-70) in the first 6 weeks and dropped to a mean of around 68 minutes (SD: 46.2) by 10-12 weeks. Colic was much more frequent in the first 6 weeks (17-25%) than thereafter (11% by 8-9 weeks and 0.6% by 10-12 weeks) according to modified Wessel criteria and lowest in Denmark and Japan.Conclusions: Fuss/cry duration drops significantly after 8-9 weeks of age with colic as defined by modified Wessel criteria being rare in infants older than 9 weeks. Colic or excessive fuss/cry may be more accurately identified by defining fuss/cry above the 90 th percentile in the chart provided based on the review.

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“…Even the secular rise in myopia suggests changes in brain chemistry, as it is mediated by the neurotransmitter acetylcholine [31,32]. More directly, there is evidence of changes in the dimensions of the head, face, and brain [33][34][35] (see also [12,36] for lists of additional references, and [37] for evidence of changes in very young children).…”

Section: Suggestion 2: Consider Other Traitsmentioning

confidence: 99%

Future Efforts in Flynn Effect Research: Balancing Reductionism with Holism

Mingroni¹

2014

J. Intell.

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Abstract:After nearly thirty years of concerted effort by many investigators, the cause or causes of the secular gains in IQ test scores, known as the Flynn effect, remain elusive. In this target article, I offer six suggestions as to how we might proceed in our efforts to solve this intractable mystery. The suggestions are as follows: (1) compare parents to children; (2) consider other traits and conditions; (3) compare siblings; (4) conduct more and better intervention programs; (5) use subtest profile data in context; and (6) quantify the potential contribution of heterosis. This last section contains new simulations of the process of heterosis, which provide a plausible scenario whereby rapid secular changes in multiple genetically influenced traits are possible. If there is any theme to the present paper, it is that future study designs should be simpler and more highly focused, coordinating multiple studies on single populations.

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

Cited by 104 publications

References 89 publications

Can GE-Covariance Originating in Phenotype to Environment Transmission Account for the Flynn Effect?

Can GE-Covariance Originating in Phenotype to Environment Transmission Account for the Flynn Effect?

Systematic Review and Meta-Analysis: Fussing and Crying Durations and Prevalence of Colic in Infants

Future Efforts in Flynn Effect Research: Balancing Reductionism with Holism

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