See it, grab it, or STOP! Relationships between trait impulsivity, attentional bias for pictorial food cues and associated response inhibition following in-vivo food cue exposure

Impulsivity is associated with appetitive behaviour such as heightened sensitivity to cues of reward. Impulsivity may thus confer a vulnerability to weight gain by virtue of over-responsiveness to rewarding appetitive cues. This vulnerability should be detectable as heightened cognitive and behavioural responsiveness to food cues, namely, an attentional bias to food-stimuli, subjective wanting, and loss of inhibitory control. We examined this proposition by measuring reactions to acute, in-vivo, food-cue exposure in low-impulsive and high-impulsive individuals. We expected that high-impulsive individuals would: (1) show a greater attentional bias towards pictorial food cues presented after in-vivo food cue exposure; (2) show a greater appetitive reaction to high-calorie snack foods; and (3) show poorer inhibitory control after in vivo exposure compared to control. Fifty female participants (25 yr ± 1.1; 24 kg/m2 ± 0.6) randomly allocated to either a high-calorie food-cue exposure or food-neutral control condition subsequently completed a food-cue visual probe reaction time task, subjective ratings of appetitive state and the Stop-Signal task. A significant Group-by-Duration interaction indicated that high-impulsives show slowed disengagement (longer RTs for 2000 ms duration) of pictorial food stimuli compared to their low-impulsive counterparts. Conversely, the low impulsive group show greater attentional bias than the high impulsive group (faster RTs) at the 500 ms duration, indicating speeded detection of pictorial food cues. High-impulsives showed poorer response inhibition compared to low-impulsives following in-vivo food-cue exposure. Impulsivity did not significantly moderate the effect of in-vivo cue-exposure on desire-to-eat ratings. The evidence we obtained regarding inhibitory control following in vivo food cue exposure suggests that high-impulsive individuals may be prone to overeat when their reward systems are activated, a hypothesis that requires further confirmation.