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Equality in Educational Policy and the Heritability of Educational Attainment.

Colodro-Conde L, Rijsdijk F, Tornero-Gómez MJ, Sánchez-Romera JF, Ordoñana JR - PLoS ONE (2015)

Bottom Line: The action of effect is hypothesized to be a decrease of shared environmental (e.g., family socioeconomic status or parents' education) influences on educational attainment, giving more room for genetic differences between individuals to impact on the variation of the trait.However, this hypothesis has not yet found consistent evidence.Our results support the role of educational policy in affecting the relative weight of genetic and environmental factors on educational attainment, such that increasing equality in educational opportunities increases heritability estimates by reducing variation of non-genetic familial origin.

View Article: PubMed Central - PubMed

Affiliation: Murcia Twin Registry, Department of Human Anatomy and Psychobiology, University of Murcia, & IMIB-Arrixaca, Murcia, Spain.

ABSTRACT
Secular variation in the heritability of educational attainment are proposed to be due to the implementation of more egalitarian educational policies leading to increased equality in educational opportunities in the second part of the 20th century. The action of effect is hypothesized to be a decrease of shared environmental (e.g., family socioeconomic status or parents' education) influences on educational attainment, giving more room for genetic differences between individuals to impact on the variation of the trait. However, this hypothesis has not yet found consistent evidence. Support for this effect relies mainly on comparisons between countries adopting different educational systems or between different time periods within a country reflecting changes in general policy. Using a population-based sample of 1271 pairs of adult twins, we analyzed the effect of the introduction of a specific educational policy in Spain in 1970. The shared-environmental variance decreased, leading to an increase in heritability in the post-reform cohort (44 vs. 67%) for males. Unstandardized estimates of genetic variance were of a similar magnitude (.56 vs. .57) between cohorts, while shared environmental variance decreased from .56 to .04. Heritability remained in the same range for women (40 vs. 34%). Our results support the role of educational policy in affecting the relative weight of genetic and environmental factors on educational attainment, such that increasing equality in educational opportunities increases heritability estimates by reducing variation of non-genetic familial origin.

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Evolution of the main indicators of Spain’s educational system from 1940 to 1974.(A) Educational attainment in Spain by year of birth. (B) Mean years of schooling by sex and year of birth for cohorts at 19 and 24 years old. Data source: Historical Statistics of Spain. 19thand 20thCenturies. Fundación BBVA [23]
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pone.0143796.g001: Evolution of the main indicators of Spain’s educational system from 1940 to 1974.(A) Educational attainment in Spain by year of birth. (B) Mean years of schooling by sex and year of birth for cohorts at 19 and 24 years old. Data source: Historical Statistics of Spain. 19thand 20thCenturies. Fundación BBVA [23]

Mentions: In spite of the interest of this question a definitive answer remains elusive and the role of educational policy on heritability estimations still generates controversy [2]. Part of this debate stems from the practical impossibility to isolate the specific effects of educational policy from the impact of its social milieu. The enquiry on this kind of topic is subject to restrictive assumption since no empirical analysis, in natural conditions, can separate the impact on EA of policy implementation and socioeconomic factors. Thus far, research on this topic has relied mainly on comparisons between countries with different educational systems or between time periods by using cut-points not directly related to changes in educational policies (e.g., pre- vs. post-war). Spain’s recent history offers an opportunity to incorporate new insights into this question, as the country experienced drastic changes in educational policy during the 20th century. One of the most important milestones during the second part of the century was the 1970 General Law on Education. This law marked an important change between the post-Spanish civil war education system and a more modern system which facilitated the adaptation of Spain to its geopolitical environment. Specifically, this law extended mandatory education up to 14 years old; a shift towards modern pedagogic approaches; the introduction of the same curricula for boys and girls; or the regulation of vocational training within secondary education. In general it was a landmark for the introduction of the principle of equality in educational opportunities within the Spanish educational system. Those changes, together with a global increase in the socioeconomic conditions in Spain, fostered the educational level of the country and increased EA for both genders [23]. Fig 1A and 1B shows some of the relevant changes that took place in EA from the early 1940’s to mid-1970’s in Spain. While the percentage of people with no studies remained stable since the end of the Spanish Civil War (1939), a decrease in this magnitude together with a rise in people accessing secondary or higher education starts for people born at the beginning of the 1960’s [23].


Equality in Educational Policy and the Heritability of Educational Attainment.

Colodro-Conde L, Rijsdijk F, Tornero-Gómez MJ, Sánchez-Romera JF, Ordoñana JR - PLoS ONE (2015)

Evolution of the main indicators of Spain’s educational system from 1940 to 1974.(A) Educational attainment in Spain by year of birth. (B) Mean years of schooling by sex and year of birth for cohorts at 19 and 24 years old. Data source: Historical Statistics of Spain. 19thand 20thCenturies. Fundación BBVA [23]
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664401&req=5

pone.0143796.g001: Evolution of the main indicators of Spain’s educational system from 1940 to 1974.(A) Educational attainment in Spain by year of birth. (B) Mean years of schooling by sex and year of birth for cohorts at 19 and 24 years old. Data source: Historical Statistics of Spain. 19thand 20thCenturies. Fundación BBVA [23]
Mentions: In spite of the interest of this question a definitive answer remains elusive and the role of educational policy on heritability estimations still generates controversy [2]. Part of this debate stems from the practical impossibility to isolate the specific effects of educational policy from the impact of its social milieu. The enquiry on this kind of topic is subject to restrictive assumption since no empirical analysis, in natural conditions, can separate the impact on EA of policy implementation and socioeconomic factors. Thus far, research on this topic has relied mainly on comparisons between countries with different educational systems or between time periods by using cut-points not directly related to changes in educational policies (e.g., pre- vs. post-war). Spain’s recent history offers an opportunity to incorporate new insights into this question, as the country experienced drastic changes in educational policy during the 20th century. One of the most important milestones during the second part of the century was the 1970 General Law on Education. This law marked an important change between the post-Spanish civil war education system and a more modern system which facilitated the adaptation of Spain to its geopolitical environment. Specifically, this law extended mandatory education up to 14 years old; a shift towards modern pedagogic approaches; the introduction of the same curricula for boys and girls; or the regulation of vocational training within secondary education. In general it was a landmark for the introduction of the principle of equality in educational opportunities within the Spanish educational system. Those changes, together with a global increase in the socioeconomic conditions in Spain, fostered the educational level of the country and increased EA for both genders [23]. Fig 1A and 1B shows some of the relevant changes that took place in EA from the early 1940’s to mid-1970’s in Spain. While the percentage of people with no studies remained stable since the end of the Spanish Civil War (1939), a decrease in this magnitude together with a rise in people accessing secondary or higher education starts for people born at the beginning of the 1960’s [23].

Bottom Line: The action of effect is hypothesized to be a decrease of shared environmental (e.g., family socioeconomic status or parents' education) influences on educational attainment, giving more room for genetic differences between individuals to impact on the variation of the trait.However, this hypothesis has not yet found consistent evidence.Our results support the role of educational policy in affecting the relative weight of genetic and environmental factors on educational attainment, such that increasing equality in educational opportunities increases heritability estimates by reducing variation of non-genetic familial origin.

View Article: PubMed Central - PubMed

Affiliation: Murcia Twin Registry, Department of Human Anatomy and Psychobiology, University of Murcia, & IMIB-Arrixaca, Murcia, Spain.

ABSTRACT
Secular variation in the heritability of educational attainment are proposed to be due to the implementation of more egalitarian educational policies leading to increased equality in educational opportunities in the second part of the 20th century. The action of effect is hypothesized to be a decrease of shared environmental (e.g., family socioeconomic status or parents' education) influences on educational attainment, giving more room for genetic differences between individuals to impact on the variation of the trait. However, this hypothesis has not yet found consistent evidence. Support for this effect relies mainly on comparisons between countries adopting different educational systems or between different time periods within a country reflecting changes in general policy. Using a population-based sample of 1271 pairs of adult twins, we analyzed the effect of the introduction of a specific educational policy in Spain in 1970. The shared-environmental variance decreased, leading to an increase in heritability in the post-reform cohort (44 vs. 67%) for males. Unstandardized estimates of genetic variance were of a similar magnitude (.56 vs. .57) between cohorts, while shared environmental variance decreased from .56 to .04. Heritability remained in the same range for women (40 vs. 34%). Our results support the role of educational policy in affecting the relative weight of genetic and environmental factors on educational attainment, such that increasing equality in educational opportunities increases heritability estimates by reducing variation of non-genetic familial origin.

Show MeSH