The primary goal of this study was to examine possible differences in threat bias acquisition across development. The current study aimed to 1) examine if threat bias could altered in 8, 12, and 18-year old children and explore possible age-related differences in threat bias acquisition 2) examine age-related differences in the relations between bias change and stress reactivity 3) examine pubertal development and its possible relations to bias change and stress reactivity and 4) explore temperamental traits and their possible relation to threat bias acquisition. To address these aims, the current study utilized an attention bias modification (ABM) with three age groups (8-year-old, 12-year-old, and 18-year-old children) to train attention allocation toward threat-related stimuli. After training, participants underwent a stress task and were assessed on emotional reactivity to stress. Data were also collected on pubertal development, trait anxiety, trait fearfulness, and social sensitivity.

Overall, the results indicated that the training paradigm was partially successful in altering children's threat bias, however, age was related to bias change. Results indicated that participants, regardless of age group, responded faster on the dot-probe task over time, suggesting the training procedure increased vigilance to threat. Results did not show a main effect of bias change from pre-training to post-training; however, there was a significant age group difference in threat bias acquisition. The 8-year old group displayed a greater threat bias change than did the 18-year old group. In partial support of the hypotheses, findings suggested that there were some group differences between stress reactivity and bias change. As well, decreases in anxiety reported stress reactivity after completion of a speech task were associated with more advanced pubertal development. Lastly, while pubertal development scores correlated with threat bias acquisition, self-reported temperamental trait characteristics did not relate to threat bias acquisition. While there is a clear need for the continued study of ABM across development, the current study is one of the first to show age differences in threat bias acquisition and its' relations to stress reactivity and pubertal development.