Electrophysiological evidence for enhanced representation of food stimuli in working memory

Abstract

Studies from our laboratory have shown that, relative to neutral objects, food-related objects kept in working memory (WM) are particularly effective in guiding attention to food stimuli (Higgs et al. in Appetite, 2012). Here, we used electrophysiological measurements to investigate the neural representation of food versus non-food items in WM. Subjects were presented with a cue (food or non-food item) to either attend to or hold in WM. Subsequently, they had to search for a target, while the target and distractor were each flanked by a picture of a food or non-food item. Behavioural data showed that a food cue held in WM modulated the deployment of visual attention to a search target more than a non-food cue, even though the cue was irrelevant for target selection. Electrophysiological measures of attention, memory and retention of memory (the P3, LPP and SPCN components) were larger when food was kept in WM, compared to non-food items. No such effect was observed in a priming task, when the initial cue was merely identified. Overall, our electrophysiological data are consistent with the suggestion that food stimuli are particularly strongly represented in the WM system.

Dietary self-control influences top–down guidance of attention to food cues

“…The overall data indicate that cues held in working memory had a greater effect on subsequent stimulus selection than cues that were merely identified – this matches prior research (e.g., Soto et al, 2005 ). Irrespective of whether they were held in working memory or not, food cues exerted stronger effects than non-food cues on subsequent selection also in line with previous findings ( Higgs et al, 2012 ; Rutters et al, 2014 ). In addition, the effect of working memory load (the longer all-round RTs when cues were held in working memory compared with when they were merely identified) was reduced for food compared with non-food items.…”

“…All participants had normal to corrected-to-normal-vision. Sample size was determined a priori on the basis of the effect sizes obtained in our previous studies ( Higgs et al, 2012 ; Rutters et al, 2014 ).…”

“…When this happens, the re-appearing item can capture the participants’ attention, even when it is irrelevant to the subsequent selection task. Interestingly, this re-appearance effect was typically much stronger when the first item was held in working memory than when it was merely identified (in the bottom–up priming condition) and it was stronger for food items than non-food items ( Higgs et al, 2012 ; Rutters et al, 2014 ). Like the bottom–up priming effect, the effect of working memory stimulus can be involuntary, influencing search even when it does not predict the search target ( Soto et al, 2005 ).…”

“…This ability of food to attract attention may be linked to its rewarding properties, which act to ‘drive’ attention to food in a bottom–up manner; food items attract attention because they are perceptually salient ( Robinson and Berridge, 1993 ; Castellanos et al, 2009 ). However, recent evidence from our laboratory suggests that higher level cognitive processes also direct attention to food, such that merely thinking about food can modulate the extent to which it captures attention; “top–down” modulation of attention ( Higgs et al, 2012 ; Rutters et al, 2014 ). The proposed mechanism underlying this effect is that holding specific information in working memory causes attention to be involuntarily drawn to similar stimuli in subsequent search displays ( Soto et al, 2005 ; Soto and Humphreys, 2007 ).…”

Make up your mind about food: A healthy mindset attenuates attention for high-calorie food in restrained eaters

“…RUNNING TITLE Mindset influences attention bias for food 5 Kumar, Higgs, & Humphreys, 2015). Thus, emerging evidence seems to suggest that variations in thoughts or mindsets about food (as state variable) influence perception and possibly attention for food.…”