Time cost reduces the generalization of fearful avoidance.

Excessive generalization of avoidance behavior is considered a core symptom of anxiety disorders. Avoidance behavior associated with anxiety often involves a certain cost, usually in the form of a reward that is foregone. Avoidance behavior can also be time-consuming, resulting in an additional cost. Little research has examined how time cost influences fearful avoidance generalization. Furthermore, rare studies have investigated how different levels of avoidance costs shape this generalization process. This study therefore focused on how the magnitude of time costs affects the degree to which fearful avoidance is generalized. After the fear conditioning stage, participants were divided into two avoidance time-cost groups. The high-cost group (18-s time delay) spent more time when choosing to avoid danger than the low-cost group (4.5-s time delay). Linear mixed models were employed to investigate the group differences in avoidance generalization. The results revealed a significant effect of time cost on avoidance of the CS+ and the generalization stimuli that were most similar to it, with the high-cost group exhibiting lower avoidance rates than the low-cost group. These findings highlight time cost as an important contextual factor in fearful avoidance behavior and suggest potential implications for interventions development.