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

Abstract

In the current study we examined an associative learning mechanism by which food cues (signaling low- versus high-calorie food) can bias instrumental responses directed toward those foods. To investigate the clinical relevance of this mechanism, we used a computerized Pavlovian-to-instrumental transfer task and compared performance of 19 severely obese individuals to that of 19 healthy-weight controls matched for age, education and gender. During the response-priming test we exposed participants to both food pictures and to Pavlovian cues predictive of those food pictures, and examined their biasing effect on instrumental choice. As expected, obese participants showed higher priming rates for palatable, high-calorie foods (potato chips and chocolate) relative to low-calorie foods (lettuce and courgette) whereas healthy-weight individuals did not show a difference between priming rates for these two food types. We also included various measures of impulsivity as well as a slips-of-action task designed to investigate the balance between goal-directed and habitual behavioral control in these two groups. We did not find any evidence of increased impulsivity or reliance on a habitual strategy during the slips-of-action task, in obese participants.General Scientific Summary: Our environment is full of cues signaling the availability of tasty, but often unhealthy, foods. This study suggests that severely obese individuals are particularly sensitive to high-calorie food cues whereas low-calorie food cues have little effect on their behavior.

Dissociable corticostriatal circuits underlie goal‐directed vs. cue‐elicited habitual food seeking after satiation: evidence from a multimodal MRI study

“…This line of research stresses the importance, therefore, of carefully regulating advertising aimed at selling unhealthy, high‐calorie snacks – especially when aimed at children. In related research, we have demonstrated that these cueing effects are indeed stronger with high‐calorie than with low‐calorie snack cues in adolescents (Watson et al ., ) and severely obese individuals (Watson et al, ). Combined with the demonstration that this associative (PIT) mechanism is not flexibly modulated by changes in motivation (e.g.…”

Goal-directed control in Pavlovian-instrumental transfer.

“…Finally, the data are interesting in light of a recent experiment by Watson et al (2017), who found that obese participants showed stronger PIT effects for high-calorie foods than low-calorie foods. The authors suggested that, because outcome value was established before training, obese participants might have formed weaker Pavlovian and instrumental links with the low-calorie foods than the high-calorie foods.…”

“…was superimposed on the Pavlovian stimulus, above the four outcome options ("CRISPS", "POPCORN", "CASHEWS" and "NACHOS"). The four options were arranged vertically and were ordered randomly on each trial, and participants selected an option using the mouse (see e.g., Watson, Wiers, Hommel, Gerdes, & de Wit, 2017, for a similar procedure). The correct outcome (see Table 1) was then presented, regardless of the participant's response.…”

Pavlovian‐to‐instrumental transfer in Anorexia Nervosa: A pilot study on conditioned learning and instrumental responding to low‐ and high‐calorie food stimuli

“…Garbusow et al, ; Garbusow et al, ; Hogarth & Chase, ; Hogarth & Chase, ; Martinovic et al, ; Vogel et al, ) or food‐related behaviour (e.g. Colagiuri & Lovibond, ; Watson, Wiers, Hommel, Gerdes & de Wit, ). A specific PIT effect is characterized by an increase of instrumental responding for a reward outcome in the presence of a conditioned stimulus associated with that outcome.…”

“…A specific PIT effect is characterized by an increase of instrumental responding for a reward outcome in the presence of a conditioned stimulus associated with that outcome. For example, Watson et al () found for obese individuals that a stimulus associated with high‐calorie food increased responding for high‐calorie foods demonstrating that aberrant eating behaviour may be influenced by conditioned food‐related stimuli. Consequently, the PIT paradigm seems to be a useful tool to investigate whether in AN, the confrontation with conditioned disorder‐compatible stimuli triggers pathological behaviour to achieve the goal of weight loss.…”