The Effects of Social Stress on Memory: If, How and When

Physical stress, such as from the cold-pressor test, has been robustly associated with altered memory retrieval, but it is not yet clear whether the same happens following psychosocial stress. Studies using psychosocial stressors report mixed effects on memory, leading to uncertainty about the common cognitive impact of both forms of stress. The current study uses a stepped replication design, with four near-identical experiments, each differing by a single critical factor. In three experiments we induced psychosocial stress after participants encoded word stimuli, then assessed retrieval after a prolonged delay. These experiments found no group level influence of postencoding stress on recognition of neutral words or cued recall of word-pairs, but a small effect on recollection of semantically-related words. There was, however, some indication of positive relationships within the stress group between measures of stress (cortisol in experiment 1 and self-reported-anxiety in experiment 3) and recollection of single word stimuli. In the fourth experiment, we found that psychosocial stress immediately before retrieval did not influence word recognition. Overall, our findings demonstrate that psychosocial stress has a typically modest impact on memory, lower than previously claimed, but that individual differences in stress responsivity, particularly for tasks that tap recollection, may help to explain variability in previous findings.