Genetic and Environmental Influences on Thin-Ideal Internalization

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thin‐ideal, internalization, body image, disordered eating, twin study, heritability, Tripartite Model

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Objective: Current research on the etiology of thin‐ideal internalization focuses on psychosocial influences (e.g., media exposure). The possibility that genetic influences also account for variance in thin‐ideal internalization has never been directly examined. This study used a twin design to estimate genetic effects on thin‐ideal internalization and examine if environmental influences are primarily shared or nonshared in origin.

Method: Participants were 343 postpubertal female twins (ages: 12–22 years; M = 17.61) from the Michigan State University Twin Registry. Thin‐ideal internalization was assessed using the Sociocultural Attitudes toward Appearance Questionnaire‐3.

Results: Twin modeling suggested significant additive genetic and nonshared environmental influences on thin‐ideal internalization. Shared environmental influences were small and non‐significant.

Discussion: Although prior research focused on psychosocial factors, genetic influences on thin‐ideal internalization were significant and moderate in magnitude. Research is needed to investigate possible interplay between genetic and nonshared environmental factors in the development of thin‐ideal internalization.


Complete List of Authors: Pamela K. Keel, S. Alexandra Burt, Michael Neale, Steven Boker, Cheryl Sisk, Kelly L. Klump

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Journal of Eating Disorders, v. 45, issue 8, p. 942-948