Whether or not to eat: A controlled laboratory study of discriminative cueing effects on food intake in humans.

There is a wealth of data showing a large impact of food cues on human ingestion, yet most studies use pictures of food where the precise nature of the associations between the cue and food is unclear. To test whether novel cues which were associated with the opportunity of winning access to food images could also impact ingestion, 63 participants participated in a game in which novel visual cues signalled whether responding on a keyboard would win (a picture of) chocolate, crisps, or nothing. Thirty minutes later, participants were given an ad libitum snack-intake test during which the chocolate-paired cue, the crisp-paired cue, the non-winning cue and no cue were presented as labels on the food containers. The presence of these cues significantly altered overall intake of the snack foods; participants presented with food labelled with the cue that had been associated with winning chocolate ate significantly more than participants who had been given the same products labelled with the cue associated with winning nothing, and in the presence of the cue signalling the absence of food reward participants tended to eat less than all other conditions. Surprisingly, cue-dependent changes in food consumption were unaffected by participants' level of contingency awareness. These results suggest that visual cues that have been pre-associated with winning, but not consuming, a liked food reward modify food intake consistent with current ideas that the abundance of food associated cues may be one factor underlying the 'obesogenic environment'.