External Eating Behaviour Effects Performance in Food Picture Flanker Task

External eaters demonstrate an automatic bias towards food stimuli and increased motivational drive to consume palatable foods. In an environment where food and food related stimulus are increasingly present, this attentional bias may lead to over-consumption and weight gain if not controlled. This experimental study investigated external eaters' cognitive processes when exposed to conflicting food images. A modified Flanker task using food pictures was undertaken on 31 participants. Participants responded quickly and accurately to a central target food picture while trying to ignore flanking food pictures. The flankers either facilitated the response choice (congruent) or conflicted with the response choice (incongruent). The difference between incongruent and congruent trials, the flanker effect, reflects the level of distraction, or conflict, experienced. Responses to different food groups (high/low fat and high/low sugar) were compared with a “low fat low sugar” baseline condition. Results showed (1) overall reaction times correlated with emotional eating and negative affect, (2) significant flanker effects of a similar size were found for all food group comparisons, (3) flanker effect magnitude positively correlated with positive affect and negatively correlated with external eating. This indicates external eaters were more effective at ignoring distraction from irrelevant food stimuli. We propose this may indicate that over time external eaters develop a controlled cognitive strategy, focusing more strongly on target foods, to help inhibit distraction from palatable foods. If this suggestion is true, this strategy would require additional cognitive resources and may be subject to failure when resources are low, as seen by periods of over consumption.