Over-generalization of dangerous stimuli is a possible etiological account of anxiety. Recently, we demonstrated it could result from alterations in early perceptual mechanisms, i.e., a fundamental change in the way the stimulus is perceived. Yet it is still unclear if these mechanisms already exist in youth, or develop only later. The purpose of this study was therefore to explore the mechanism of generalization in youth suffering from anxiety disorders. Children and adolescents with anxiety disorders and age-matched control participants underwent a conditioning task where a loss or gain outcome was associated with two well-separated tones. A generalization probe then followed in which different surrounding tones were presented and classified. Generalization curves and changes in discrimination abilities were compared between groups and according to the background variables. We found that patients had lower perceptual discrimination thresholds after conditioning, and tended to have wider generalization curve. Relative enhanced generalization was observed in adolescents with anxiety, in males, and as the level of anxiety rose. Our results suggest that over-generalization in anxiety can start already during adolescence, and may suggest that an early perceptual source can give rise to later more cognitive over-generalization during adult anxiety.
Keywords: Anxiety; adolescents; amygdala; children; generalization; perceptual mechanisms.