Through the Frosted Glass Pane: Blunted Physiological Responses to Extremely Under- and Over-Sized Body Pictures in Female Adolescents with Obesity—An Experimental Pilot Study

Problematic weight control behaviors during adolescence are associated with an increased risk of chronic obesity. Understanding how adolescents with obesity respond to body-related visual cues may offer insights into underlying motivational deficits. This experimental pilot study employed a peripherally measured startle reflex paradigm to assess the involuntary emotional responses to images of underweight, normal-weight, and overweight bodies. Twenty female adolescents with obesity and 21 normal-sized control subjects between 14 and 21 years of age were presented with photos of female bodies. Images from the International Affective Picture System served as reference material. The Self-Assessment Manikin was used as the subjective measure, while startle reflex magnitude and skin conductance response served as objective measures. A significant interaction emerged for body-related stimuli. In the normal-weight group, underweight and overweight body images elicited increased skin conductance responses (indicative of heightened attention) and potentiated startle reflexes (indicative of behavioral avoidance). In contrast, adolescents with obesity exhibited a general physiological down-regulation and a subjective vs. objective dissociation across all body image categories, suggesting a dysfunction in motivational processing. Our findings suggest diminished physiological salience of body-related cues in obese adolescents, which may undermine intrinsic motivation for weight loss. The limited sample size restricts generalizability.