Accuracy of body size estimation: Role of biopsychosocial variables

Body Image 3 (2006) 163–171 www.elsevier.com/locate/bodyimage

Accuracy of body size estimation: Role of biopsychosocial variables Marita P. McCabe *, Lina A. Ricciardelli, Geeta Sitaram, Katherine Mikhail School of Psychology, Deakin University, Vic., Australia Received 22 July 2005; received in revised form 24 January 2006; accepted 25 January 2006

Abstract This study evaluated factors related to the perceptual disturbances of body image. Using a digital body image computer program, 191 participants (107 women, 82 men) adjusted an image of their body to the perceived actual size at five body regions; chest, waist, hips, thighs and calves. A neutral object (a vase) was also adjusted to partial out the level of perceptual distortion present with a neutral object. Men and women overestimated the size of the neutral object and their body image. Among women, overestimation was primarily predicted by high levels of depression, and media and peer influences to be thinner and increase muscles. Among men, overestimation was predicted by high BMI, media influences to lose weight and increase muscles, and peer influences to increase muscles. These findings suggest that perceptual accuracy of body image is primarily predicted by biopsychosocial influences. # 2006 Elsevier Ltd. All rights reserved. Keywords: Perception; Overestimation; Body image; Sociocultural influences; Depression

Accuracy of body size estimation: Is it perceptual or emotional in nature? Perceptual disturbances of body image are characterized by inaccurate perceptions, resulting in the reporting of an overestimation or underestimation of the size of body regions or of the whole body image (Cash & Deagle, 1997; Stewart & Williamson, 2004). Although primarily investigated among eating disordered populations, the research on perceptual accuracy among normal populations (particularly women) has been an area of growing interest. The findings from the research have implications for the identification, prevention and treatment of body image disturbances.

* Corresponding author at: School of Psychology, Deakin University, 221 Burwood Highway, Burwood, Vic. 3125, Australia. Tel.: +61 3 9244 6856; fax: +61 3 9244 6858. E-mail address: [email protected] (M.P. McCabe). 1740-1445/$ – see front matter # 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.bodyim.2006.01.004

Most previous research on body image has investigated the factors that may be associated with body image dissatisfaction, that is a subjective assessment of the level of satisfaction with one’s current size or shape. Several variables have been implicated in the research on body image dissatisfaction, but the impact of these factors on estimates of body size has not been explored. These factors loosely fit into a biopsychosocial model of body image disturbance (Ricciardelli, McCabe, Holt, & Finemore, 2003). The current study was designed to investigate the validity of this model in the prediction of accuracy of body image estimation, which is the extent to which one overestimates or underestimates the size of one’s body. The major factors in the biopsychosocial model investigated in the current study included body mass index (BMI), depression and messages from peers and the media about the person’s body. It is proposed that the perception of body image results from two important processes. Firstly, perception of the physical dimensions of the body is achieved through the reception and integration of a variety of

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sensory inputs, including those of a visual, tactile and kinaesthetic nature (Slade, 1985). Perception of body image and its distortion may result from sensory factors such as stimulus intensity, visual deficiencies and attentional factors (Gardner, Sorter, & Friedman, 1997; Thompson & Gardner, 2002). Secondly, non-sensory factors may contribute to the perception of body image. These non-sensory factors include cognitive and affective factors based on an individual’s beliefs, schemas and prior knowledge about one’s body (e.g., Thompson, Heinberg, Altabe, & Tantleff-Dunn, 1999). Previous studies have employed control objects, where participants estimate the dimensions of a box or a block of wood, as well as representations of themselves (Birtchnell, Dolan, & Lacey, 1987; Slade & Russell, 1973). In the current study, a vase was used to control for perceptual estimation errors due to factors unrelated to the perception of one’s own body. It was expected, consistent with the findings of Birtchnell et al. (1987) and Slade and Russell (1973), that respondents would evidence higher levels of estimation inaccuracies for their bodies than for the vase. Inconsistencies within the research on estimation accuracy of body image have been linked to the varying techniques employed to assess this construct, (e.g., Brodie, Slade, & Rose, 1989; Cash & Brown, 1987; Gardner, 1996). See Thompson and Gardner (2002) for a review of these techniques. Some researchers have reported that both men and women overestimate (i.e., report their body to be larger than its actual size) body size with site-estimation techniques and underestimate (i.e., report their body to be smaller than its actual size) with whole-body procedures (e.g., Gardner, Jones, & Bokenkamp, 1995; Slade, 1985). Improving upon the limitations of previous techniques, a new computergenerated technique has been developed, which will be employed in the current study. Presented with a whole body image, the technique allows, within a single trial, the independent manipulation of five regions of the body (chest, waist, hips, thighs and calves) (Stanford & McCabe, 2002). The research has revealed inconsistent results with regard to the relationship between BMI and the accuracy of estimating body size. While some research has suggested that the accuracy of body size estimation is significantly related to the BMI of individuals who fall within a normal weight range (Dolan, Birtchnell, & Lacey, 1987), other studies have found that BMI values are not related to estimation accuracy (Bergstron, Stenlund, & Svedjehall, 2000; Monteath & McCabe, 1997). Studies have revealed that overweight men and women tend to underestimate their body size, while

normal and underweight men and women estimated themselves to be larger than they actually were (Smeets, Smit, Panhuysen, & Ingleby, 1998). A possible explanation as to why the accuracy of body size estimations vary in relation to BMI is that individuals attempt to bring their body size closer to average body size. On the other hand, some researchers have found that both over- and under-weight individuals have a tendency to overestimate their body size (e.g., Cash & Green, 1986; Collins, McCabe, Jupp, & Sutton, 1983). The contradictions and inconsistencies throughout the research may be due to methodological differences, such as samples comprising more women than men (Monteath & McCabe, 1997), or different methods of measurement. Slade (1985) proposed that persons with low mood have an increased tendency to attend to negative body information and evaluate their body more negatively, resulting in estimation inaccuracy in body size. Taylor and Cooper (1986) also reported that within a sample of women with no history of eating disorders, depressed mood was related to body size overestimation. Garner and Garfinkel (1981) suggested that the degree of perceptual inaccuracy of specific regions of the body may vary according to the importance placed on them from sociocultural messages. A preoccupation with body image, transmitted socioculturally via the media, family and peers has been implicated in the etiology of body image disturbances and can affect how one cognitively and affectively responds to their body. Western culture values an increasingly thinner, ectomorphic female body ideal (e.g., Thompson & Stice, 2001; Tiggemann & Pickering, 1996). With regard to the male ideal body image, sociocultural influences promote a large and muscular, mesomorphic, V-shaped body, which is stereotypically associated with masculinity, power and strength (e.g., Cafri, Thompson, Ricciardelli, McCabe, Smolak, & Yesalis, 2005; McCabe & Ricciardelli, 2004; Tiggemann, 2002). Within this framework, it would be expected that men would be more likely to demonstrate estimation inaccuracy in regions that are involved in the definition of the sociocultural ideal of a male body, such as the chest and upper torso area in particular. Women, on the other hand, would be expected to demonstrate inaccuracy in areas such as the mid and lower torso (Nagel & Jones, 1992). Consistent with this proposal, Dolan et al. (1987) reported that both men and women significantly overestimated body size, with men markedly overestimating the chest region, and women primarily overestimating the waist region. Pope, Gruber, and Mangweth (2000) found that men chose an ideal body that was 28 lb more muscular than themselves.

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Other research findings have been less consistent, with no reported significant differences between men and women in the degree of estimation accuracy of the various body regions (Gardner & Bokenkamp, 1996; Thompson & Thompson, 1986). Gendebein and Smith (1992) reported a significant overestimation of the lower torso relative to the upper torso among women, whereas no such distinction in overestimation was found with men. Bergstron et al. (2000) reported that both men and women overestimated the waist, buttocks and thighs, with women overestimating these areas more than men, whereas Ben-Tovim, Walker, Murray, and Chin (1990) found that women in the study overestimated their shoulders and thighs. Leit, Gray, and Pope (2002) found that even brief exposure to muscular images resulted in an increased level of inaccuracy in the estimation of body size among men. These results suggest that the overestimation of body size in men and women may bring men closer to the sociocultural ideal for men, but take women further away from the sociocultural ideal for women. The present study utilized a whole-body technique, where a distorted image of the individual’s own body was presented, allowing them to adjust individual body parts (Stanford & McCabe, 2002). The degree of estimation accuracy was measured by the percentage of overestimation and underestimation. This technique is superior to former methods, as it allows individuals to make the images wider or thinner an unlimited number of times, until they are satisfied that the image represents their ‘actual’ size. The study compared the degree of estimation accuracy for specific body parts with the degree of estimation accuracy for the equivalent regions of an inanimate object, that is, a vase. It was expected that there would be better estimation accuracy for the vase. The inclusion of the vase acted as a control object to control for perceptual errors inherent in the task, but unrelated to one’s body size. The biopsychosocial factors were BMI, depression, peer, and media influences to change weight. In keeping with the biopsychosocial model that has been developed to explain body dissatisfaction, it was predicted that BMI, depression and messages from the media and peers to lose weight and increase muscles would predict estimation accuracy for body size for men and women. These predictors were expected to be greater for men for the upper body, and for women for the lower body. It was expected that men would be more likely to demonstrate estimation errors in the chest region, while women would be more likely to demonstrate estimation errors in the waist, hip and thigh regions. Men and

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women with a high BMI were also expected to demonstrate higher levels of estimation inaccuracy. It was also expected that both men and women with higher levels of depression would display higher levels of estimation inaccuracy. It was expected that there would be a higher levels of estimation inaccuracy for the various parts of the body compared to the vase. It was also expected that the level of estimation accuracy would be predicted by messages about ideal body size from the media and peers. Method Participants The participants were 82 men and 107 women aged between 18 and 36 years. The mean age of the men was 23.71 (SD = 4.46), and for women was 24.71 (SD = 4.99). BMI ranged from 18 to 36. The mean BMI for men was 23.74 (SD = 3.65) and for women was 23.97 (SD = 3.45). Participants were drawn from a wide range of cultural backgrounds. Participants reported no history of eating disorders or psychiatric illness. Materials Digital body image computer program The digital body image computer program included two components. The first component enabled participants to manipulate an onscreen 10 cm image of a neutral object (a vase of varying dimensions) at five different regions. The second component enabled participants to manipulate a full frontal image of their entire body at five specific sites: chest, waist, hips, thighs and calves. Digital images of each individual and the neutral object were provided through use of a Kodak DC290 digital camera and Photoshop program (see Stanford & McCabe, 2002 for further details of the equipment). Depression scale The depression scale (seven items) from the short form of the depression, anxiety and stress scale (DASS; Lovibond & Lovibond, 1995) was used to assess levels of depression. Participants were required to indicate the extent to which they experienced various feelings and symptoms related to depression over the past week, by circling a number on a Likert scale ranging from 0 ‘did not apply to me’ to 3 ‘applied to me very much, or most of the time’. Higher scores indicated higher degrees of depression. The DASS has reported an internal consistency of 0.91 for the depression scale (Lovibond & Lovibond, 1995).

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Sociocultural influences questionnaire Sociocultural pressures to lose weight and increase muscles were assessed by two sub-scales from the Perceived Sociocultural Influences on Body Image and Body Change Questionnaire (McCabe & Ricciardelli, 2001). The peer influences sub-scale assessed perceived influences on weight (three items) and muscularity (four items) from the individual’s peers. The media sub-scale assessed perceived influences on weight (three items) and muscularity (four items) from the media. All items were rated on a five-point Likert scale (1 = strongly agree to 5 = strongly disagree). Satisfactory internal consistencies and reliabilities for the scales have been reported (McCabe & Ricciardelli, 2001). Coefficient alpha for each of these sub-scales in the current study were 0.78. Procedure Participants were recruited by placing signs at various locations on the university campus asking for volunteers to participate in the study on perception of body image. Participants were instructed to wear dark and fitted clothing to the testing session, and height and weight were measured and recorded. Standing in front of a plain, opaque backdrop to achieve an image with a monotone background, a digital image of each respondent was taken according to the body image program set-up instructions, the digital image was then transferred to the laptop computer and presented as an approximately 10 cm image on the screen. The program consisted of two components. In the first component, participants were simultaneously presented with two images of a neutral object (vase), one pre-distorted by the program (each of the five regions distorted by 20%) and one undistorted. Participants were instructed to alter the size of the various regions of the neutral object’s image to match the size of the adjacent undistorted image. The second component simultaneously presented two images of the participant’s body, one pre-distorted by the program and one undistorted. Again, instructions were given to alter the size of the five body regions of the distorted image, to provide an image that matched the undistorted image. Five measures of estimation accuracy were obtained for both the neutral object and body image condition. Half of the distorted images were larger than the actual size, and half were smaller than the actual size. Individuals were able to separately alter the size of their body and the vase, increasing or decreasing the width, by clicking on the body part or region, the left mouse button decreasing the size and the right mouse button increasing the size of the particular body part in

1% increments. The image could be adjusted from 90% smaller than actual size to 130% larger than actual size without distorting the height of the image. Morphing of images resulted in body contours still being linked after body parts were distorted. A measure of estimation accuracy was obtained from the percentage discrepancy between the actual size of the region and the estimated size of the region (positive values indication overestimation and negative values indicating underestimation). Half the participants viewed the vase first, and half viewed their own body first. One estimation was obtained of each of the five sites of the vase and the person’s body. Participants were then also required to complete a demographic information form and the questionnaires described earlier. Measurements of height and weight were taken to provide the calculation of a BMI (weight in kilograms divided by height in meters, square). The entire procedure took each participant approximately 30 min to complete. Results Means and standard deviations, expressed as percentage overestimation (positive scores) or underestimation (negative scores), for men and women for the five regions of the neutral object (1–5) and body (chest, waist, hips, thighs, calves) are shown in Table 1. Both men and women overestimated the regions of the neutral object, and each of the regions of the body. Body image distortion A repeated measures MANOVA was performed to determine the effect of gender and the object of Table 1 Mean and standard deviations for the differences in the degree of estimation accuracy of the neutral object and body regions for men and women Object

Region

Vase Body Vase Body Vase Body Vase Body Vase Body

Upper Chest Upper-mid Waist Lower-mid Hips Upper-bottom Thighs Lower-bottom Calves

Men (N = 82)

Women (N = 107)

M

SD

M

SD

4.62 9.33 4.33 8.57 3.35 6.61 1.96 11.17 2.52 13.62

7.81 9.86 7.39 10.95 6.44 10.53 5.07 11.25 6.27 11.55

4.85 8.58 3.16 6.64 3.35 5.68 2.07 10.21 1.71 11.78

7.40 9.59 6.50 10.59 6.41 9.40 5.29 11.59 5.83 12.77

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distortion (a vase versus their own body) on levels of perceptual accuracy for five areas (upper/chest, uppermid/waist, lower-mid/hips, upper-bottom/thighs, and lower-bottom/calves). The analysis revealed a significant Pillai’s value for the object of distortion, F(5, 183) = 28.53, p < 0.001, but not for gender, F(5, 183) = 2.25, p > 0.05 or for the interaction between gender and object, F(5, 183) = 1.70, p > 0.05. Univariate analyses revealed a significant effect for the object of distortion on chest, F(1, 187) = 21.96, p < 0.001, waist, F(1, 187) = 17.76, p < 0.001, hips, F(1, 187) = 13.24, p < 0.001, thighs, F(1, 187) = 87.01, p < 0.001, and calves, F(1, 187) = 112.77, p < 0.001. Examination of the means (see Table 1) demonstrated that both men and women reported higher levels of estimation inaccuracy in relation to the five regions of their own bodies in comparison to the vase. Predictors of estimation accuracy Multiple regression analyses were performed to determine which of the independent variables (BMI, depression, media influence to lose weight, media

Table 2 Summary of variables predicting the degree of estimation accuracy of the body regions in men Variable Chest area BMI Media influences to lose weight Media influences to increase muscle Peer influences to increase muscle Waist area BMI Media influences to lose weight Peer influences to increase muscle Hip area Vase distortion lower mid region BMI Peer social influences to increase muscle Thigh area BMI * ** ***

p < 0.05. p < 0.01. p < 0.001.

B

Beta

2

sr

t

2.70**

1.22

0.22

0.04

2.22*

0.97

0.24

0.05

2.28*

0.21 0.85

0.21 0.23

0.04 0.04

2.26* 2.38*

1.45

0.27

0.06

2.70**

**

Thigh area Depression Media influences to lose weight

0.27 1.08

0.22 0.28

0.04 0.05

2.27* 2.48*

***

Calf area Depression Peer influences to lose weight

0.30 1.57

0.22 0.22

0.04 0.04

2.31* 2.08*

2.39*

1.07

0.23

0.05

2.21*

1.26 1.21

0.42 0.31

0.14 0.09

3.90*** 3.04***

1.19

0.23

0.05

2.27*

0.37

0.11

3.29*** 2.87 2.74**

3.07

t

0.06

0.06

1.13

sr2

0.27

0.25

0.07 0.07

Beta

0.99

0.97

0.32 0.28

Chest area Media influences to lose weight Media influences to increase muscle Peer influences to lose weight

B

2.26*

2.34 2.75**

0.91 1.35

Variable

0.04

0.05 0.08

0.10

Table 3 Summary of variables predicting the degree of estimation accuracy of the body regions in women

0.25

0.26 0.30

0.33

influence to increase muscle, peer influence to lose weight, peer influence to increase muscle), predicted the degree of estimation accuracy of each of the five body regions (chest, waist, hips, thigh, and calf). Estimation accuracy of the neutral object was also included as an independent variable to account for the proportion of variance attributed to purely sensory factors. Since it was expected that there may be gender differences in the predictors of distortion, analyses were conducted separately for men and women. The significant predictors for men for each of the body regions are summarized in Table 2, and for women in Table 3. The results demonstrated for men that the level of estimation accuracy of the chest area was significantly predicted by the independent variables, F(7, 73) = 3.92, p < 0.001, R = 0.52, R2 = 0.27. The unique predictors were high BMI, low media influences to lose weight, and high media peer influences to increase muscle (see Table 2). The level of estimation accuracy of the waist area was significantly predicted by the independent variables, F(7, 73) = 4.77, p < 0.001, R = 0.56, R2 = 0.31. The unique predictors were high BMI, low media influences to lose weight, high peer influences to increase

0.77

*

0.72 1.04

0.54

167

Waist area Media influences to increase muscle Hip area Depression Media influences to increase muscle Peer influences to lose weight

* **

p < 0.05. p < 0.01.

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muscle (see Table 2). The level of estimation accuracy of the hip area was significantly predicted by the independent variables, F(7, 73) = 5.38, p < 0.001, R = 0.58, R2 = 0.34. The unique predictors were the high levels of vase distortion in the same region, high BMI, and high peer influences to increase muscles (see Table 2). The level of estimation accuracy of the thigh area, was significantly predicted by the independent variables, F(7, 73) = 2.45, p < 0.05, R = 0.40, R2 = 0.16. The only unique predictor was high BMI (see Table 2). The level of estimation accuracy of the calf area was not significantly predicted by the independent variables, F(7, 73) = 1.83, p > 0.05. For women, the level of estimation accuracy of the chest area was significantly predicted by the independent variables, F(7, 99) = 3.80, p < 0.001, R = 0.46, R2 = 0.21. The unique predictors were high media influences to lose weight, low media influences to increase muscle and high peer influences to lose weight (see Table 3); the level of estimation accuracy of the waist area was significantly predicted by the independent variables, F(7, 99) = 2.60, p < 0.05, R = 0.35, R2 = 0.12. The only unique predictor was low media influences to increase muscles (see Table 3). The level of estimation accuracy of the hip area was significantly predicted by the independent variables, F(7, 99) = 4.03, p < 0.001, R = 0.47, R2 = 0.22. The unique predictors were high levels of depression, low media influences to increase muscle, and high peer influences to lose weight (see Table 3). The level of estimation accuracy of the thigh area was significantly predicted by the independent variables, F(7, 99) = 3.06, p < 0.01, R = 0.42, R2 = 0.18. The unique predictors were high levels of depression, and high media influences to lose weight (see Table 3). The level of estimation accuracy of the calf area was significantly predicted by the independent variables, F(7, 99) = 2.82, p < 0.01, R = 0.41, R2 = 0.17. The unique predictors were high levels of depression, and high peer influences to lose weight (see Table 3). Discussion The results of this study demonstrated that participants were more accurate in estimating the five vase regions than they were in estimating the five body regions, suggesting that other factors were involved in body image distortion. These findings are consistent with other studies that have employed inanimate objects, where participants accurately estimated the size of inanimate objects but were inaccurate in their estimation of their own size (Cash & Green, 1986; Gardner & Moncrieff, 1988; Szmanski & Seime, 1995).

Garner and Garfinkel (1981) suggested that the degree of estimation accuracy of specific body sites may vary according to the emphasis placed on them from sociocultural messages. Given that sociocultural influences predominantly emphasize the chest for men, and the hips, waist and thighs for women, it was expected that women would overestimate their waist, hips and thighs, whereas men would overestimate their chest region. However, this hypothesis was not supported, since it was found that men and women were very similar in the extent to which they overestimated the size of the five body regions. These findings are consistent with previous studies that have found that both men and women overestimate body size (Birtchnell, Lacey, & Harte, 1985; Casper, Halmi, Goldberg, Eckert, & Davis, 1979; Dolan et al., 1987). Discrepancies across studies may be due to methodological differences, such as the type of apparatus used to measure estimates of body size, randomised estimations of width or varying distance of participants from the stimulus materials (Stewart & Williamson, 2004). Alternatively, the current results may suggest that men and women are now focused on all aspects of their bodies, as they both attempt to achieve a slim toned (for women) and muscular body (for men). However, an interesting finding from the current study is that by men overestimating their body size, it is likely to bring them closer to the muscular sociocultural ideal for men. In contrast, overestimation would move women further from the sociocultural ideal for women. These findings suggest that just as men evidence lower levels of body dissatisfaction than women (Davison & McCabe, 2005), men may also be more likely than women to perceive that their bodies conform to the sociocultural ideal for their gender. Future research needs to focus more closely on the relationship between the ideal body of men and women and their accuracy of body size estimation. Although men and women were found to overestimate each of the five body regions, the source of overestimation may be different. As suggested above, women may have overestimated their body size because they believed they were ‘fatter’ than they really were, and men may have overestimated their size because they perceived themselves to be more ‘muscular’ than their actual size. A possible way of clarifying whether or not this was the case would be to include a question on the body image computer program, prior to participants adjusting their ‘actual’ body size, asking whether the image on the screen ‘should be fatter’, ‘should be slimmer’ or ‘should be more muscular’. BMI was a significant predictor of the estimation accuracy of four of the five body parts for men, but did not predict the estimation accuracy of any body parts for

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women. Larger men were more likely to perceive they had a larger body size for each of their body parts (except for the calves), but accuracy of body size estimation was equally likely to occur for women independent of their BMI. This result is consistent with the finding that women of all weights and sizes are attempting to obtain a slimmer body through internalization of the thin ideal (Stice, Shaw, & Nemeroff, 1998), and may be both dissatisfied with their body, as well as likely to inaccurately estimate the size of their body. In contrast, male body image may be more dependent upon BMI, with men with a higher BMI perceiving themselves to be larger than their actual size, and men with a lower BMI perceiving themselves to have a less muscular body build (McCabe & Ricciardelli, 2004). Past research has demonstrated the normative nature of body dissatisfaction among women (Thompson et al., 1999), whereas significantly lower proportions of men are dissatisfied with their body, and dissatisfaction may be particularly characteristic of overweight and underweight men (McCabe & Ricciardelli, 2004). Unfortunately, the current study was not able to examine the impact of muscularity versus body fat in terms of the extent of accuracy of body size estimation among men. Depression was a significant predictor of women’s estimation accuracy for three out of five body parts (all lower body parts), but did not predict estimation accuracy for men. These findings are consistent with those obtained by others in relation to body dissatisfaction among women (e.g., Obring, Graber, & BrooksGunn, 2002; Paxton, Schultz, Wertheim, & Muir, 1999; Stormer & Thompson, 1996). However, as for the studies on body dissatisfaction, the direction of this relationship is unclear, as recent evidence suggests that it may be depression that leads to body image disturbance, rather than vice versa (e.g., Stice & Bearman, 2001). As for body dissatisfaction, these results indicate that there is a much weaker association between accuracy of body size estimation and negative affect for men compared to women. Women’s sense of self appears to be more strongly associated with their body image than for men, and so they perceive their bodies to be larger than they are, (Davison & McCabe, 2005). If they are feeling depressed they may, then, be more likely to feel bad about their body as well as feel bad about other aspects of themselves. This proposal needs to be empirically evaluated. The results of the study demonstrated that perceived sociocultural influences to both lose weight and increase muscle predicted accuracy of body size estimation for both men and women. Not surprisingly, the direction of

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these influences were different for men and women: higher pressures to lose weight increased estimation inaccuracy for women and reduced it for men; higher pressures to increase muscles increased estimation inaccuracy for men and reduced it for women. The most consistent sociocultural factor to predict estimation inaccuracy of each of the body parts for men was higher levels of perceived peer influence to increase muscles, with higher levels of perceived media pressure to increase muscles as well as lower levels of both media pressure to lose weight being important predictors. For women, the most consistent sociocultural influence was lower levels of perceived media pressure to increase muscles, with both higher levels of both perceived media pressure to lose weight and perceived pressure from peers to lose weight also playing a significant role in the accuracy of body image estimation. These findings applied to the estimation of all body parts, including those more closely related to the sociocultural ideal for each gender prescribed by society. These results suggest that the peer messages most strongly predictive of body image accuracy estimations were those most closely related to the stereotyped behaviors of that gender: increasing muscles for men, and losing weight for women. However, the media messages that predicted the accuracy estimations of body for both men and women related to both losing weight and increasing muscle. The images that are portrayed by the media are slim toned bodies for both men and women, (e.g., McCabe & Ricciardelli, 2004; Thompson & Stice, 2001), and this media ideal appears to impact on increasing muscle and losing weight for both men and women. Clearly, this proposal needs to be explored further in future studies. The finding that only moderate proportions of the variance of the perceptual distortion could be explained by the variables included in the current study indicates that other variables that were not included may represent significant predictors of estimation accuracy. For example, Thompson and Spana (1991) conducted a study of body size estimation among college females and found that size overestimation was associated with visuospatial dysfunction. The role of visuospatial ability in one variable that could be explore further in future research in this area. The findings in the current study are limited by the small sample size, the limited range of predictor variables, and the limited age range of respondents. Clearly, the findings from this study need to be replicated with a larger study before we can draw strong conclusions. The current study only included a limited range of predictive variables, and these need to be

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extended in future studies. A broader range of respondents also need to be included, so that we can determine the generalizability of the findings to other age group and other cultural groups. Future studies also need to include a control condition that involves distortion of a male (for men) or female (for women) body other than their own, to control for estimation accuracy effects inherent in adjusting for the size of particular body parts in a body other than one’s own body. In conclusion, the findings of the study revealed that both men and women demonstrate estimation inaccuracies in their body image. No significant gender differences in the degree of estimation inaccuracies were found. However, different biopsychosocial variables were found to predict the degree of estimation accuracy among men and women. The findings of the current study support the assertion that the accuracy of body image estimations is not exclusively a defining factor of eating disorders (Hsu, 1982), as these estimation inaccuracies are a phenomenon also found among the general population. It is proposed that developing a greater understanding of the degree and nature of body estimation accuracy in the normal population will provide invaluable information in our understanding of body image disturbance, and so inform intervention and prevention programs in this area. References Ben-Tovim, D. I., Walker, M. K., Murray, H., & Chin, G. (1990). Body size estimates: Body image or body attitude measures? International Journal of Eating Disorders, 9, 57–67. Bergstron, E., Stenlund, H., & Svedjehall, B. (2000). Assessment of body perception among Swedish adolescents and young adults. Journal of Eating Disorders, 6, 385–391. Birtchnell, S. A., Dolan, B. M., & Lacey, J. H. (1987). Body image distortion in non-eating disordered women. International Journal of Eating Disorders, 6, 385–391. Birtchnell, S. A., Lacey, J. H., & Harte, A. (1985). Body image distortion in bulimia nervosa. British Journal of Psychiatry, 147, 408–412. Brodie, D. A., Slade, P. D., & Rose, H. (1989). Reliability measures in distorting body image. Perceptual and Motor Skills, 69, 723–732. Cafri, G., Thompson, J. K., Ricciardelli, L. A., McCabe, M. P., Smolak, L., & Yesalis, C. (2005). Pursuit of the muscular ideal: Physical and psychological consequences and putative risk factors. Clinical Psychology Review, 25, 215–239. Cash, T. F., & Brown, T. A. (1987). Body image in anorexia nervosa and bulimia nervosa: A review of the literature. Behavior Modification, 11, 437–521. Cash, T. F., & Deagle, E. A. (1997). The nature and extent of body image disturbances in anorexia nervosa: A meta-analysis. International Journal of Eating Disorders, 22, 107–125. Cash, T. F., & Green, G. K. (1986). Body weight image among college women: Perception, cognition and affect. Journal of Personality Assessment, 50, 290–301.

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