Feedback-based learning is a process in which decisions are made based on the previous feedback. This learning process is influenced by acute stress. However, different laboratory stressors elicit different physiological response patterns, which may influence feedback processing differently. Moreover, individual differences in stress reactivity may be associated with reward sensitivity. Therefore, the present study investigated the effects of psychosocial and physical stress on feedback-based learning. The relationship between stress reactivity and reward sensitivity was also examined. Ninety-two college-aged subjects were assigned into the mental arithmetic (MA) task or the cold pressor task (CPT) group. All subjects performed a feedback-based learning task prior to and after the stressor. Cardiovascular reactions, stress experiences, and learning outcomes were recorded during tasks. Trait differences in behavioral inhibition and activation (BIS/BAS) were also measured. Results indicated different patterns of cardiovascular reactions to the MA and CPT. Learning outcomes were differentially influenced by the MA and CPT. Moreover, subjective stress scores were negatively correlated with the learning rate in the pre-stress learning task. Additionally, BAS Drive subscale score was related to the processing of positive feedback. The results suggested that physical and psychosocial stress influence learning through distinct neural mechanisms and psychological processes. Motivational processes underlie the relationship between stress reactivity and reward sensitivity. This study extended research on stress and learning, and the findings have applied implications in various areas. / Ph. D.