Testing a load theory framework for food-related cognition

The way we process rewarding stimuli is widely held to play a key role in normal and abnormal behavior. Biased processing of food—arguably the most primal form of reward—has been strongly implicated in the obesity crisis. Paradoxically, however, existing evidence suggests that both too much and too little attention can potentially lead to overeating. Here we sought to explain this contradiction within the framework of the load theory of attention, while also elucidating the relatively understudied role of memory biases. In 3 experiments, we presented food and nonfood images as irrelevant distractors during a letter search task with high and low levels of perceptual load, followed by a forced choice recognition task. As predicted, increasing perceptual load consistently powerfully reduced distraction by food and nonfood images alike. Similarly, food images encountered under high perceptual load were less likely to be recognized in a surprise memory test. Unexpectedly, however, there was a striking absence of attentional bias to food above and beyond salient nonfood stimuli, either within-subjects or in relation to traits implicated in food-biases. By contrast, a food memory bias was consistently observed across participants, and appeared independent of attentional biases. Food memory was consistently heightened in individuals with high levels of trait disinhibition (a measure of opportunistic eating). Our findings suggest that attention and memory for food and nonfood are similarly impacted by perceptual load. We discuss implications of the load theory framework for the wider literature on food-related cognition and for real world eating behaviors.