Stress Differentially Affects Memory for Positive and Negative Words, Independent of Its Proximity to the Learning Experience
Stress can enhance, impair, or have no effect on learning and memory, depending on several factors. We have examined how the temporal proximity of stress to a learning experience affects one’s memory for that experience. Seventy-two participants were exposed to stress (cold pressor test) or no stress by placing their dominant hands in a bath of cold (1±1°C) or warm (36±1°C) water, respectively. Cardiovascular measurements, saliva samples, and pain/stress ratings were collected from participants to corroborate stress induction. Either immediately or 30 minutes after water bath exposure, participants read a list of 30 words that varied in emotional valence. Twenty-four hours later, participants completed free recall and recognition tests to assess their memory for these words. The results indicated that participants exposed to the cold pressor test exhibited significantly greater blood pressure and pain/stress ratings than non-stressed participants. In addition, stress, independent of temporal proximity to the learning experience, led to significantly lower recall of negative words and significantly enhanced recognition of positive words. These results lend insight into how stress differentially affects memory for positive and negative information and suggest that the temporal proximity of stress to a learning experience may not largely influence how stress affects memory.