Study explores the processing of body pictures in binge eating

Mar 29 2012

An investigation published in the current issue of Psychotherapy and Psychosomatics explores the processing of body pictures in binge eating.

Previous research suggests that the excessive influence of shape or weight concerns upon self-evaluation is strongly associated with psychological functioning in binge eating disorder. This association may be mediated both by selective attentional processes with regard to the selection of competing stimuli (e.g. own vs. other's body) and also the attentional distribution within a disorder- specific stimulus (e.g. ugly/beautiful parts of one's body). Regarding the latter, an eye-tracking study found that binge eaters (BE) and non-BE (NBE) differ with regard to the attentional processing of the self body picture (SB) compared to the processing of a 'control' body picture (CB). However, no study has tested attentional processing of body pictures when SB and CB are presented concurrently.

The aims of the present study were therefore to test whether: (1) attentional patterns for the SB/CB differ between BE and NBE; (2) different attentional patterns emerge at an early or at a later processing stage or both; (3) such biases are the result of automatic or schema-driven attentional processes. Participants were 23 female BE and 23 overweight female NBE recruited via local media. The stimuli were picture pairs including a SB (face omitted) and a weight-matched CB. Pictures were arranged in 3 blocks of 16 (randomly presented) trials of 3 s each. Both SB/CB were presented from 4 different body perspectives (front/left side/right side/back), whereby the left/right side presentation on the monitor of the SB/CB was counterbalanced. To capture automatic and schema-driven attention, the trials were presented in 2 conditions: in the cue condition (CC), participants were given information on whether the SB would appear on the left or right side of the monitor, while in the no cue condition (NCC) participants got no information on which side the SB would appear. Pictures were presented at an eye distance of 57 cm. Eye movements were measured by means of a 240-Hz Eye-Link _ Eyetracker equipped with iView Software (Sensomotoric Instruments). The mechanism is based on the determination of the center of the pupil and the corneal reflection, by which eye movements are assessed.

Overall, in the CC, the 1st fixation was more frequently directed towards the SB compared to the CB. However, in the CC, gaze frequency of the 1^st fixation towards the SB was higher in BE compared to NBE (p = 0.014), while gaze frequency towards the CB was lower in BE compared to NBE (p = 0.005). Regarding the frequency towards the SB/CC of the 2nd fixation, there was a significant main effect of body (p <0.001) and significant interactions for body X group (p<0.001) and for body X condition (p =0.036). Again, in the CC, the 2nd fixation was more frequently directed towards the SB compared to the CB. Additionally, in the CC gaze frequency of the 2nd fixation towards the SB was higher in BE compared to NBE (p = 0.022), while gaze frequency towards the CB was lower in BE compared to NBE (p = 0.024). For the duration of the 1^st fixation on SB/CB there were significant main effects for body (p<0.001), condition (p = 0.006) and a significant interaction of body X condition (p<0.001). Regarding the duration of the 2^nd fixation, there was a significant main effect for body (p<0.001) and significant interactions for group X condition (p = 0.019), body X condition (p<0.001) and group X condition X body (p = 0.048). Thereby, overall fixations were longer for the SB compared to the CB.

However, in the CC, NBE directed their gaze longer on the CB than BE (p =0.007). Gaze variables did not significantly correlate with BDI. However, in the NCC, Body Shape Questionnaire scores of the BE group correlated significantly and positively with gaze frequency (2nd fixation) towards the SB.

In summary, the opposite viewing patterns found may be mechanisms underlying the high body dissatisfaction of BE. However, even though the patterns were robust also when controlling for BMI, further studies should replicate the findings in a larger and weight-matched obese control sample.