Correlational analysis revealed that total EDI score was positively related to depression, alexithymia and trait anxiety; r(52) = .64, p < .001, r(52) = .30, p < .001 and r(52) = .49, p < .001 respectively. Similarly, depression was positively related to alexithymia and trait anxiety; r(52) = .36, p = .01 and r(52) = .60, p < .001 respectively. Furthermore, alexithymia was positively related to trait anxiety; r(52) = .66, p < .001. As a result, it is possible that mood and alexithymia may have contributed to the differences in face processing reported above. Therefore, we assessed the interrelationships between mood, alexithymia, eating-related psychopathology and measures of face processing (attentional processing and emotion recognition).
4.3.6. The influence of mood, alexithymia and eating-related psychopathology on face processing
Correlational analysis revealed that initial fixation bias scores (direction and duration) were not significantly related to depression, trait anxiety, alexithymia or any of the EDI subscales, all tests p >.05. Similarly, gaze duration bias scores (for happy and angry
136 expressions) were not significantly related to scores on the body dissatisfaction or bulimia subscales of the EDI or to depression, alexithymia and trait anxiety; all tests p > .05. However, gaze duration bias scores for both happy and angry expressions were significantly related to scores on the drive for thinness subscale (DFT) of the EDI; r(52) = -.35, p = .01 and r(52) = -.29, p = .04 respectively. This suggests that higher DFT scores were associated with longer fixation times on neutral expressions compared to emotional.
4.4. Discussion
The primary aim of this study was to examine if the bias towards threatening (i.e. angry) faces that has been observed in patients with eating disorders generalised to participants with non-clinical levels of eating-related psychopathology. A further aim was to determine if participants high in eating-related psychopathology would demonstrate avoidance in response to threatening (angry) faces. Eye-tracking technology was used to monitor continuous attentional deployment in participants scoring high and low on the eating and weight-related subscales of the Eating Disorder Inventory (EDI) during free visual exploration of a series of face pairs (angry-neutral and happy-neutral).
The prediction that high EDI scorers would demonstrate a greater tendency to initially fixate on the angry faces than would low EDI scorers was not supported by our findings, as both groups exhibited a tendency to orient attention towards neutral faces. Similarly, the prediction that high EDI scorers would spend longer during these initial fixations looking at angry faces than would low scorers was not supported. Interestingly, both groups spent longer looking at emotional faces compared to neutral, but there was no bias towards angry over happy in either group. Taken together these findings fail to provide evidence of an orientation bias towards threat in participants ‘at risk’ of developing an eating disorder. These findings were also replicated in our continuous analysis, as no significant relationships emerged between eating-related psychopathology (scores on the EDI subscales) and the percentage of initial fixations or the duration of these fixations. The lack of evidence for an orienting of attention towards both angry and happy faces conflicts with much of the previous literature on attentional bias in eating disorders (Cardi et al., 2012; Harrison et al., 2010a; Kanakam et al., 2013). However, it is possible that these discrepancies are a result of the type of participant studied. In this way, the previously observed attentional biases towards threat may not be generalisable to non-clinical samples.
137 Although not significant, high EDI scorers were found to exhibit longer total gaze durations on the neutral faces compared to low EDI scorers which partially supports our initial hypothesis. Specifically, high scorers looked longer at neutral faces when presented with both angry-neutral and happy-neutral pairs which can be interpreted as avoidance of emotion. The finding of avoidance in those high in eating-related psychopathology supports previous research which has demonstrated emotional avoidance among eating disorder patients (Davies et al., 2011; Quinton, 2004). The avoidance of threat (angry faces) in the current sample also supports the notion that anger is perceived as a threatening and highly salient emotion for those high in eating- related psychopathology (Fox, 2009; Fox & Power, 2009; Ioannou & Fox, 2009). Subsequent pleasantness ratings also lend support to this idea, with high EDI individuals rating angry expressions as significantly less pleasant than did the low EDI group.
Interestingly, trait anxiety was shown to have a partial influence on attentional orienting towards threat. Specifically, when examining participants’ direction bias scores, the previously non-significant main effect of group became significant when the impact of trait anxiety had been statistically taken into account. Furthermore, analysis of the gaze duration bias scores revealed that the significance of the main effect of emotion was considerably reduced when trait anxiety has been taken into account. Overall, these findings suggest that concurrent trait anxiety may have some effect on the processing of emotional faces in the current sample. To date, the impact of underlying mood variables on attentional processing within eating-related psychopathology has remained relatively unacknowledged in the literature. Therefore, replication of these findings is necessary before conclusions regarding the impact of trait anxiety on the processing of emotional faces can be drawn.
In addition, findings from the continuous analysis confirm that eating-related psychopathology was associated with a bias away from the emotional faces. However, this relationship was only apparent with scores on the drive for thinness (DFT) subscale of the EDI and not bulimia or body dissatisfaction. Importantly, the significant relationship between DFT and the avoidance of emotional faces remained after controlling for trait anxiety, depression and alexithymia. However, the relationship between trait anxiety and emotional avoidance became non-significant after controlling for DFT. This may imply that concerns with weight, shape and dieting are key factors in explaining the emotional avoidance response observed. Taken together, these findings suggest that dieting and weight concerns may lead an individual to avoid emotional (particularly threat-related) information.
138 From a theoretical perspective, both motivational and cognitive mechanisms may contribute to the avoidance response observed in high EDI individuals (Kaye, 2008; Kaye, Fudge, & Paulus, 2009). Based on the current findings, it may be suggested that individuals high in eating-related psychopathology initially deploy attention to emotional expressions in the same way that healthy eaters do. However, the gaze data reveal that it is only after an initial phase, whereby the particular stimulus is encoded and identified as an emotional expression that disordered eaters begin to avoid this image. This is supported by findings from the emotion recognition task, which demonstrated that the high and low EDI groups did not differ significantly in their identification of both angry and happy faces. In other words, there are no differences in the incentive salience of emotional information between the high and low EDI groups initially, but it is the later dysfunctional cognitions present in highly disordered eaters which lead to the emotional avoidance observed. In this way, disorder-specific dysfunctional cognitions may attempt to resolve conflicting short- and long-term goals in high EDI individuals through the re-evaluation and subsequent avoidance of potentially harmful emotional information (Kaye, 2008).
The aim to account for the influence of important individual difference variables (depression, anxiety, alexithymia and eating-related psychopathology) on attentional processing represents one of the main strengths of the current investigation. As a result, the findings of this study may have potential explanatory power for understanding much of the variability in previous emotion processing research. To our knowledge, this is also the first study to use eye-tracking technology as a measure of attentional processing in a sample of non-clinical disordered eaters. The use of this technology to continuously monitor the allocation of attention by the participants throughout the facial attention task represents a methodological strength of the current study, as it overcomes some of the weaknesses of previously used paradigms (Stroop and dot-probe). Nevertheless, there are a few notable limitations that need to be taken into consideration. Firstly, the size of the sample was quite small which may have resulted in diminished statistical power to detect a significant effect. However, this is greater than the sample sizes reported in other eye-tracking studies involving participants with clinical (Giel et al., 2011) and non-clinical eating-related psychopathology (Gao et al., 2011; Hewig et al., 2008). The effect sizes observed in the present study were also relatively small, suggesting that the significance of the effect may not have increased with a greater sample. A further limitation concerns the number of stimuli presented in the face processing tasks of the current study. Although the number of face pairs (24) used in the facial attention task is comparable to the
139 number of picture pairs (30) presented in Giel et al. (2011), it is considerably less than the number of word pairs (120) used in Gao et al. (2011). The number of stimuli used in the facial emotion recognition task (14; two examples of each of the seven emotions) is also fewer than have been used in previous studies, for example Ridout, Thom and Wallis (2010) who presented 28 stimuli (four examples of each emotion). Using a greater number of trials would clearly have improved the reliability of the estimate of the group means; however it is unlikely that a substantially different pattern of results would have been found if the number of stimuli was increased.
In addition, it is possible that the use of ANCOVA to ‘control for’ group differences in trait anxiety may have not been a suitable method of analysis. Previously, Miller and Chapman (2001) have suggested that the covariate must be independent from the experimental effect (or independent variable). As a result, the use of ANCOVA to examine the influence of anxiety on attention processing may be questioned, as high and low EDI groups were shown to differ significantly on this variable. This may have obscured the findings and potentially compromised the interpretation of the ANCOVA (Wildt & Ahtola, 1978). Nevertheless, it is argued that when group differences on the covariate occur by chance, the use of ANCOVA is appropriate (Maxwell & Delaney, 1990). In the relatively healthy, non-clinical sample examined in the current study it is likely that differences in anxiety may have arisen by chance, therefore the use of ANCOVA in this case would be suitable. In this case, the resulting analysis would act only to reduce background ‘noise’ from the group and not anything substantive about the grouping variable.
Overall, the findings of this study do not support the notion of an early orientation bias towards threat in those with non-clinical eating-related psychopathology. However, there was clear evidence that participants with relatively high levels of disordered eating, particularly relating to drive for thinness, were more likely to attend to neutral faces rather than emotion (happy and angry), which could be interpreted as evidence of emotional avoidance. Although it is necessary to replicate these findings before reliable conclusions can be drawn, this study points towards impaired attentional processing in non-clinical eating-related psychopathology. Indeed, problems attending to emotional faces are likely to negatively impact on social functioning and could potentially act as a risk factor for the future development of a serious eating disorder in those who selectively avoid threatening emotional displays. Although preliminary in its conclusions, this study also points towards a focus on emotional factors in the treatment of eating disorders. Challenging the currently held negative perception of emotions as ‘unpleasant’ or threatening’, may therefore represent an important first
140 step towards improving emotion regulation in these individuals. In this way, encouraging the use of more effective ways of managing both positive and negative emotions may help to prevent the development of an eating disorder in those with already high levels of eating-related psychopathology. It is also hoped that a greater understanding of the factors that contribute to disordered eating-related psychopathology would also guide clinicians towards more successful eating disorder treatments.
141