Applying Comparison-Induced Distortion Theory to Body-Size Judgments

I propose a comparison-induced distortion theory account of body-size judgments wherein verbal body-size comparisons (e.g., "Kimberly is thinner than Jane," Choplin & Hummel, 2002, 2005) bias judgments of body-sizes. Two experiments tested predictions of this account. Unpredicted by previous models, Experiment 1 demonstrated that verbal comparisons affect body-size judgments even though the distribution of contextual body sizes was held constant. Experiment 2 found that verbal comparisons can sometimes bias judgments toward the values to which they are compared. An extremely thin woman was judged larger if she was compared to someone who was much larger than her than if she was compared to someone who was only slightly larger than her. These results demonstrate that research on body-size judgments cannot ignore the effects of verbal comparisons. Body-Size Judgments The goal of this paper is to propose and test a comparisoninduced distortion theory (CID theory, Choplin & Hummel, 2002, 2005) account of body-size judgments. The application of CID theory to the problem of body-size judgments was inspired by research investigating the effects of media ideals on body-size judgments (Lavine, Sweeney, & Wagner, 1999; Martin & Kennedy, 1993; Richins, 1991). Contemporary popular media glamorizes unrealistically thin women (Fouts & Burggraf, 2000; Malkin, Wornian, & Chrisler, 1999; Owen & Laurel-Seller, 2000; Spitzer, Henderson, & Zivian, 1999) and this glamorization has negative psychological consequences for women (Bessenoff, 2006; see Groesz, Levine, & Murnen, 2002, for a meta-analysis; Irving, 1990; Stice & Shaw, 1994). In particular, researchers have argued that this glamorization leads to increased body-size dissatisfaction (Garfinkel et al., 1992; Grogan, Williams, & Conner, 1996; Trampe, Stapel, & Siero, 2007), decreased self-esteem (J. K. Thompson & Thompson, 1986), negative mood (Tiggemann & McGill, 2004), feelings of shame (Sanftner, Barlow, Marschall, & Tangney, 1995), depression (Heinberg & Thompson, 1995; J. K. Thompson, 1986), and unhealthy dieting behavior (Garfinkel et al., 1992; Phelps et al., 1993; Stice, SchupakNeuberg, Shaw, & Stein, 1994; Stice & Shaw, 1994). Concern over the negative effects of this glamorization has motivated several psychological models of the affective consequences of body-size comparisons. Some have argued that the tendency to compare one’s self to glamorized, unrealistically thin media ideals (upward social comparisons, Festinger, 1954) mediates the impact of media exposure on measures such as body dissatisfaction, negative mood, depression (Bessenoff, 2006; Tiggemann & McGill, 2004), as well as disordered eating (Field, Camargo, Taylor, Berkey, & Colditz, 1999). Likewise, Thompson and his colleagues (J. K. Thompson, Heinberg, Altabe, & TantleffDunn, 1999; J. K. Thompson & Stice, 2001) have argued that women internalize media ideals and the discrepancy between their ideal sizes and their actual sizes (Higgins, 1987, 1989) causes negative psychological consequences (Bessenoff, 2006; Harrison, 2001; Strauman, Vookles, Berenstein, Chaiken, & Higgins, 1991). Although the model proposed here is strictly a cognitive model, it might be of use to researchers in further refining models of the affective consequences of media ideals. The application of CID theory to the problem of bodysize judgments was also inspired by the observation that women diagnosed with anorexia nervosa overestimate their body sizes (Bruch, 1962). Prior to Penner, Thompson, and Coovert (1991), many researchers assumed that this overestimation was involved in the etiology of the disorder. However, their research found that all thin women overestimate their body sizes. This finding suggests that overestimation probably does not play a role in the etiology of the disorder, but it does leave us with a mystery. Why should thin women overestimate their body sizes? The few papers that have tried to propose formal models of body-size judgments, rather than the affective consequences of social body-size comparisons, have invoked Helson’s (1964) adaptation-level theory (AL theory, see Choplin & Hummel, 2005; Helson, 1964; Wedell, 1995, for the mathematical implementation of this model) to explain how images in popular media influence body-size judgments (Martin & Kennedy, 1993; Richins, 1991). This theory was originally designed to explain people’s judgments of sensory stimuli such as temperatures. AL theory assumes that people judge temperatures relative to the temperature that feels normal or average to them (the adaptation level). Temperatures that are above the adaptation level are judged hot, and temperatures that are below the adaptation level are judged cold. A given temperature such as 50o Fahrenheit (10o Celsius) will feel warmer in winter than in summer because colder temperatures seem normal in winter, making this temperature high relative to the lower norm. Likewise, this theory assumes that people judge body sizes relative to the body sizes they think are normal or average. Body sizes that are larger than what people think of as normal are judged fat, and body sizes that are smaller are judged thin. A 140-lb (63.5-kg) woman will seem fatter if people think smaller sizes are normal. Popular media images of unrealistically thin women might make thinner women seem normal (Martin & Kennedy, 1993; Richins, 1991). If so, then relative to this artificially created norm thin women will be judged closer to average, average women will be judged larger than average, and large women will be judged extremely large. Choplin and Hummel (2002) proposed an alternative model of attribute evaluation (CID theory, see Choplin & Hummel, 2005, for the mathematical implementation of this