Alan McStravick for redOrbit.com – Your Universe Online
So You Think You Can Dance. Cosmo. America´s Next Top Model. Maxim. Barbie Dolls. These are but a few examples of what many social scientists have decried as being at the root of a culture obsessed with an elusive and often impossible ideal of thinness.
This study, published in the International Journal of Eating Disorders has found that genetics may make some women more vulnerable to the pressures associated with being thin. Researchers wanted to pay particular attention to the potential psychological impact of women who obsess over this ideal of thinness. They contend that changes in self-perception and behavior can lead to dissatisfaction of one´s body, a preoccupation with weight and other symptoms of eating disorders.
“We’re all bombarded daily with messages extolling the virtues of being thin, yet intriguingly only some women develop what we term thin ideal internalization,” said Jessica Suisman, lead author on the study and a researcher at MSU.
“This suggests that genetic factors may make some women more susceptible to this pressure than others.”
In an attempt to isolate the role of genetic factors in the pressure to be thin, the study worked with more than 300 sets of female twins aged 12-22. They initially measured the participants´ desire to look like people they see in movies, magazines and on television. Once determined, the base-line level of thin idealization was used to measure and compare identical twins, who shared 100 percent of their genes, with fraternal twins, who share only half of their siblings´ genetic code.
What the team found was that identical twins very often share closer levels of thin idealization than fraternal twins do. An in-depth analysis showed that the heritability thin idealization appears to be around 43 percent. This indicates that almost half the reason that women differ in their idealization of thinness can be explained by differences in their genetic make-up.
The environmental factors mentioned above were also found to have a significant influence on the participants of the study. Observing differences between twins´ environments, the researchers hypothesized that the development of thin idealization had to do with more than just the cultural attitudes and exaggerated ideals of beauty that women throughout Western societies are exposed to.
“We were surprised to find that shared environmental factors, such as exposure to the same media, did not have as big an impact as expected,” Suisman said. “Instead, non-shared factors that make co-twins different from each other had the greatest impact.”
Non-shared environmental influences typically include experiences that twins do not share with one another. Examples of this include: involvement by one twin in a weight-focused sport like dance or gymnastics; one twin being exposed to more media that promotes thinness than the other; one of the twins having a friendship group that places importance on weight. Specific environmental triggers were not considered in this study.
“The broad cultural risk factors that we thought were most influential in the development of thin-ideal internalization are not as important as genetic risk and environmental risk factors that are specific and unique to each twin,” said Suisman. Kelly Klump, MSU professor of psychology and co-author on the study, also noted that it is well established that a broad range of factors can contribute to the development of eating disorders.
“This study reveals the need to take a similar approach to the ways in which women buy in to pressure to be thin, by considering how both genetic and environmental factors contribute to the development of thin-ideal internalization,” Klump concluded.