Influence Of Uncertainty Tolerance On Fear Generalization In Adolescence

Fear is a human inborn emotion which can help individuals defend against threatening situations.Although fear is essential for survival,its impairment is a hallmark of psychiatric disorders including anxiety disorder.Fear generalization is a common emotional phenomenon,including perceptual-based and category-based fear generalization.Previous studies mainly focused on the perceptual-based generalization,but the category-based generalization mechanism of more ecological validity needs to be studied.From the perspective of development,adolescence is a critical and susceptive period of anxiety disorders.At this stage,individual fear responses and brain circuits are significantly different from those of adults.The study of adolescent fear emotions and their neural mechanism is conducive to the prevention and early intervention of mood disorders.At present,the most commonly used treatment for anxiety disorder is exposure therapy based on fear conditioning.However,due to potential individual differences,many patients relapsed or were not completely cured after treatment.Uncertainty tolerance is one of the pivotal factors that directly affects individual judgment and responses to potential threats.Therefore,the present study explored the influence of uncertainty tolerance on the perceptual-based and category-based fear generalization through two experiments.Experiment 1,a 2（Uncertainty tolerance: High;Low）× 4（Generalized stimulus: GS1;GS2;GS3;GS4）mixed experimental design was conducted to explore the influence of uncertainty tolerance on the perceptual-based generalization of adolescents and its neural mechanism.The results showed that adolescents with high or low uncertainty tolerance level had no significant difference in fear acquisition.However,in the fear generalization phase,the adolescents with low uncertainty tolerance had stronger generalization,and the activation of the right dorsolateral prefrontal cortex was insufficient.Experiment 2 divided the generalization stimuli into high,medium,and low correlation levels according to the degree of classification correlation with dangerous stimuli.Conducted a 2（Uncertainty tolerance: High;Low）× 3（Generalization stimulus: GS1;GS2;GS3）mixed experimental design,experiment 2 explored the effect of uncertainty tolerance on category-based fear generalization in adolescents.Studies found that low uncertainty tolerance adolescents had greater fear response at acquisition phase than high uncertainty tolerance adolescents.In the fear generalization phase,adolescents with low uncertainty tolerance could not inhibit the fear response to safe stimuli,and the activation of the right dorsolateral prefrontal cortex was insufficient.In conclusion,we have three major findings:（1）Students with low uncertainty tolerance had increase fear generalization based on perception and conceptual clues;（2）In the process of fear generalization,the activation of the right dorsolateral prefrontal cortex was insufficient in low uncertainty tolerance;（3）Compared with perceptual information,individuals with low uncertainty tolerance are more sensitive to conceptual information.The current study contributes to the theoretical basis of adolescent fear generalization,and provide reference suggestions for middle school mental health education from the following three aspects:（1）Identifying students with low uncertainty tolerance characteristics can effectively prevent anxiety disorders in junior high school;（2）students’ negative expectations in the face of uncertainty can be reduced through curriculum activities and individual counseling;（3）Strengthening safe learning of students with low uncertainty tolerance to reduce unnecessary fear.