What we remember from a stressful episode.

A stressful episode is thought to be consolidated better because of a stress-induced activation of the hypothalamus-pituitary-adrenal (HPA) axis. However, human experimental studies addressing this hypothesis directly are lacking. Thus, we investigated memories of the stressful episode itself. Furthermore, we aimed to determine the influence of stress on recollection and familiarity processes. Participants (n=63) were subjected to a psychosocial stressor (Trier Social Stress Test, TSST) or a newly developed non-stressful control condition (friendly-TSST). During both conditions, they were exposed to a committee and visual stimuli, either bound to the situation (central) or not (peripheral). The next day, participants engaged in unexpected recognition tasks. Negative affect and salivary cortisol concentration increased in stressed but not in control participants. The following day, stressed participants recognized central objects and the committees' faces better than control participants. Furthermore, recollection contributed significantly more to memory performance in stressed than in control participants. Our findings are congruent with the idea of enhanced memory binding under stress combined with enhanced memory consolidation of information acquired during stress. What we remember from a stressful episode appears to be determined by the strength of the association between the stressor and the material to be remembered.