An associative account of how the obesogenic environment biases adolescents' food choices

Abstract

Adolescents and children are the targets of much food advertising, the majority of which is for unhealthy snacks. Although the effects of advertising on food preferences and consummatory behavior are well documented, our understanding of the underlying mechanisms is still limited. The present study investigates an associative (ideomotor) mechanism by which exposure to rewarding (snack) outcomes may activate behavior that previously resulted in these rewards. Specifically, we used a computerized task to investigate whether exposing adolescents to food pictures directly, or to Pavlovian cues predictive of those food pictures, would bias their subsequent responses towards the presented/signaled food. Furthermore, we assessed whether this effect was particularly pronounced with palatable, high-calorie snacks (crisps and chocolate) relative to low-calorie snacks (tomatoes and cucumber). In two experiments, adolescents learnt that certain key presses would yield particular food pictures - some high calorie and others low calorie - before learning Pavlovian associations between cues (cartoon monsters) and these same food pictures. Subsequently, in a response-priming test, we examined the extent to which the food pictures and Pavlovian cues spontaneously primed the previously associated response. The results show that we replicated, in adolescents, previous demonstrations of ideomotor response priming in adults: food pictures biased responding towards the response that previously yielded them, and this effect transferred to the Pavlovian cues. Furthermore, the priming effect was significantly stronger for high-calorie rewards than for low-calorie. These findings indicate that the ideomotor mechanism plays an important role in the detrimental effect of our obesogenic environment, with its plethora of unhealthy food reminders, on adolescents' food-related choices.

Monetary, Food, and Social Rewards Induce Similar Pavlovian-to-Instrumental Transfer Effects

“…Participants were willing to invest more effort when reward-associated cues were presented in the background compared to a neutral cue (Figure 2), which is in line with previous PIT research in humans (Bray et al, 2008; Talmi et al, 2008; Prévost et al, 2012; Watson et al, 2014, 2016; Garofalo and di Pellegrino, 2015). Furthermore, this general PIT effect was stronger, the higher the individual level of motivation, i.e., the higher the subjective reward value (Figure 2).…”

“…When deciding how to act, it is commonly assumed that these reward-associated stimuli are compared in order to choose the option associated with the highest value. More generally, there is ample evidence that reward-predicting stimuli can consciously or unconsciously exert a strong influence on behavior (Pessiglione et al, 2008; Holmes et al, 2010; Watson et al, 2016). Despite the well-established links between rewards and actions, one important open question is whether different reward types (i.e., monetary, food or social rewards) are equally effective in motivating behavior.…”

Stimulus Control Over Action for Food in Obese versus Healthy-weight Individuals

“…This direct outcome-response (O-R) priming effect (see Figure 1 ) has been observed in the lab with demonstrations that presentation of pictures of, e.g., chocolate on a computer screen can elicit key presses that previously yielded a chocolate reward (Hogarth and Chase, 2011; Hogarth, 2012; Watson et al, 2016). However, even merely being reminded of croissants (e.g., by seeing a painting of Paris) can trigger the trip to the bakery (see Figure 1 ).…”

“…However, even merely being reminded of croissants (e.g., by seeing a painting of Paris) can trigger the trip to the bakery (see Figure 1 ). This indirect stimulus-outcome-response (S-O-R) priming effect (with Pavlovian stimuli that had been paired with food outcomes) has been demonstrated experimentally with the Pavlovian-to-instrumental (PIT) task (Bray et al, 2008; Prévost et al, 2012; Lovibond and Colagiuri, 2013; Watson et al, 2014, 2016). Watson et al (2014), for example, presented participants with abstract (Pavlovian) pictures that had previously been associated with popcorn or chocolate Smarties, while participants were free to respond for these two food rewards.…”

“…Using various associative-learning paradigms it has been demonstrated in carefully controlled laboratory settings that responding for food can be triggered by exposure to those food rewards either directly or indirectly (via Pavlovian cues previously associated with those food rewards; Watson et al, 2014, 2016). These effects are relevant for understanding the mechanism by which our obesogenic environment, filled with cues signaling the availability of tasty food, can lead to maladaptive food-seeking behavior and ultimately to obesity (Cohen, 2008; Swinburn et al, 2011; Johnson, 2013).…”