The Role of Attentional Bias in Excessive Food Consumption

New Zealand obesity rates have reached epidemic proportions. Excessive eating not only harms individual health, but also the NZ economy; health-related costs soar with rising obesity rates. The need to understand possible mechanisms driving excessive eating behaviour is now crucial. One cognitive mechanism thought to contribute to excessive eating is an attentional bias towards food stimuli. We propose this bias would be similar to the attentional bias that is consistently shown with emotional stimuli (e.g. erotic and mutilation images). In this thesis I examined attentional biases towards food stimuli and how they relate to both state (hunger) and trait (waist circumference) factors. In Experiment 1, I investigated the existence of a food-related attentional bias and whether this bias is stronger towards high calorie food images, compared to low-calorie and non-food images (household objects). Participants were asked to fast for 2 hours (to promote self-reported hunger) before completing a distraction task. This task has repeatedly shown an attentional bias to high arousal emotional images (erotic and mutilation scenes). On each trial, participants had to determine whether a target letter was a ‘K’ or an ‘N’, while ignoring centrally-presented distractors (high calorie, low calorie and household object images). Compared to scrambled images, all image types were similarly distracting. We found no support for the existence of an attentional bias towards food stimuli; nor did we find a significant association between the bias and either state or trait factors. Experiment 2 sought to conceptually replicate Cunningham & Egeth (2018) who found significant support for the existence of a food-related attentional bias. Participants completed a similar task. However, distractor relevance was manipulated by incorporating both central and peripheral distractors, to increase ecological validity. Additionally, participants were asked to fast for longer (4 hours) to increase self-reported hunger. Despite a significant distraction effect (participants were more distracted on distractor present vs. distractor absent trials) and distractor-location effect (participants were more distracted by central vs. peripheral distractors), participants did not exhibit an attentional bias towards food stimuli. Furthermore, no significant associations between the bias and either state or trait factors were found. Thus, food stimuli do not appear to rapidly capture attention the way that emotional stimuli do, at least not in this task. Future research is needed to clarify the role of cognitive mechanisms in excessive eating behaviour.