Social Learning Model of Family Influence
From a social learning perspective, disordered eating attitudes and behaviors might be learned from family members just as many other attitudes and behaviors are learned. Certainly food preferences that may have consequences for disordered eating are highly influenced by culture and rearing environment, as can be seen in Jamie’s case.
Case Study: Jamie
One problem that Jamie had with all weight loss diets was their emphasis on eating more fresh fruits and vegetables. He felt that if the number of calories he could eat was going to be restricted, he wanted to use as many calories as possible for the foods he liked and not waste any calories on foods he didn’t like. Jamie’s favorite foods were those that reminded him of his mother’s cooking. His mother had grown up in the South and made wonderful chicken-fried steak with gravy, biscuits, and fried okra. Thinking that okra was a vegetable he liked, Jamie once tried to prepare stewed okra on a diet. However, the consistency of the stewed okra was that of “snot with boogers.” It was slimy and slightly sticky, and the okra seeds were tasteless little blobs suspended in the goop. Jamie’s father also played a part in his attitudes toward food: They both felt that a meal without red meat was not a “real” meal.
Supporting a social learning model, eating disorders have been found to run in families (Ferreira, de Souza, da Costa, Sichieri, & da Veiga, 2013; Lilenfeld et al., 1998; Strober, Lampert, Morrell, Burroughs, & Jacobs, 1990). Woodside et al. (2002) found significantly elevated weight and shape concerns among parents of eating-disordered subjects compared with controls. Gershon et al. (1983) found that mothers of eating-disordered adolescents had histories of dieting more frequently than mothers of controls. Several cross-sectional studies support the idea that families may provide a context for social learning of disordered eating attitudes and behaviors (Quiles, Quiles, Pamies, Botella, & Treasure, 2013).
Agras et al. (1999) conducted a prospective longitudinal study with 41 mothers with current or past eating disorders (ED mothers) and 153 control non-ED mothers, along with their children, starting when the children were infants. Several differences emerged that pertained specifically to daughters of ED mothers. During infancy, daughters of ED mothers vomited more frequently than did daughters of non-ED mothers. There also was a significant association between ED mothers’ eating disorder symptoms and their attitudes toward the weight or shape of their daughters but not of their sons. Regardless of the child’s gender, ED mothers reported using food to reward or calm children more often, fed their children on less regular schedules, and reported that their children dawdled more while eating than did non-ED mothers. Stice, Agras, and Hammer (1999) examined rates and predictors of childhood eating disturbances based on the data collected by Agras et al. (1999). Childhood eating disturbances emerged over the course of five-year follow-up in 34% of participants. The relevant behaviors included inhibited eating, secretive eating, overeating, and overeating-induced vomiting. Interestingly, no significant gender differences were found for rates of these disturbed eating patterns, with the exception that overeating-induced vomiting was more common in boys than girls. Children’s eating disturbances were predicted by various maternal variables, including the mother’s BMI, body dissatisfaction, bulimic symptoms, and dietary restraint.
In a three-year longitudinal study of adolescent girls, the extent to which mothers had internalized the thin ideal predicted bulimic symptoms in their daughters (Linville, Stice, Gau, & O’Neil, 2011). In a 10-year follow-up study of college students, having a mother who dieted frequently predicted increased drive for thinness and bulimic symptoms in women but not men (Keel, Forney, Brown, & Heatherton, 2013). These results, unlike those of Stice et al. (1999), support a prospective relationship between disordered parental eating attitudes and behaviors and the emergence of eating disturbances in daughters but not sons.
An alternative to a social learning explanation for associations between parental concerns about eating and weight and disordered eating in daughters is that biological relatives share not only their environments but also their genetic makeup. Klump and colleagues examined scores on a measure based on the EDI in 680 eleven-year-old and 602 seventeen- year-old female twin pairs (Klump, McGue, & Iacono, 2000c) and reassessed disordered eating in the 11-year-old twins when they were 14 and 18 years old (Klump, Burt, McGue, & Iacono, 2007). In the 11-year-old cohort, correlations of EDI-based scores within twin pairs were similar for MZ and DZ twins. However, EDI correlations were significantly higher for MZ than for DZ twins in the 17-year-old cohort. Moreover, follow-up of the 11-year-old twins showed significantly higher EDI correlations for MZ than for DZ twins when they were 14 years old and again when they were 18. Reflecting these patterns, shared environmental factors (e.g., family rearing environment) significantly explained the EDI scores in the 11-year-old twins, while genetic factors significantly explained the EDI scores in twins at ages 14, 17, and 18 years. These results suggest that the rearing environment can significantly affect disordered eating attitudes and behaviors in prepubertal girls but that in adolescence genetic makeup becomes more important. The role of genetic factors in eating disorders will be covered in greater depth in Chapter 8.