Effects of attention allocation on habituation to food cues in normal weight and overweight children

Despite the rising prevalence of pediatric overweight, minimal research has been conducted to understand the basic biological processes underlying overweight in children. The present study assesses changes in physiological response (i.e., salivation) to food over time. The primary aims were to examine whether salivation patterns in children vary based on weight status and/or allocating attention to a distracter task. It was hypothesized that: (1) overweight children would not habituate (salivation at the final trial would not decrease back to baseline level), regardless of distracter task condition while the normal weight children would habituate (i.e., salivation at the final trial would decrease back to baseline level) and that (2) all children attending to the distracter task would take longer to habituate as compared to those not attending to the task. Participants were 31 normal weight and 26 overweight children ages 9 to12 years. All children were presented with nine one-minute trials of a food stimulus (French fries). During each intertrial interval, participants either listened to sequential one-minute presentations of an audio-book (distracter task) or listened to white noise (no-distracter-task control). Pattern and rate of salivation were measured using a validated procedure (the Strongin-Hinsie Peck method) and analyzed using repeated measures ANCOVA and Kaplan-Meier survival analysis. The rate of change in salivation over trials differed significantly by weight status (p=.01) but not by distracter task condition (p>.10). Specifically, regardless of distracter task condition, at the final trial of the study, normal weight children habituated to food cues while overweight children did not. Results suggest that children's physiological response to food is related to weight status. Such atypical habituation patterns could potentially lead to overconsumption, thus serving as a possible causal or maintaining factor in childhood overweight. The lack of a distracter effect is in contrast to previous findings and may be due to differences in methodology across studies. Future directions, including, (a) experiments to explore causal mechanisms, (b) experiments testing habituation in more naturalistic settings and, (c) prospective studies to determine the role of salivary response in OW, are discussed.