Cortisol broadens memory of a non-stressful social interaction

Stress and its associated hormonal cascade are known to enhance long-term memory consolidation. Recently we have shown that central details of a stressful situation (Trier Social Stress Test; TSST) are remembered better than central details of a similar but non-stressful control condition (friendly Trier Social Stress Test; fTSST). We reasoned that since cortisol concentrations increase during stress (TSST) but remain low during the control condition (fTSST), a pharmacological increase in cortisol during the fTSST might be able to mimic the stress effects observed previously. The objective of the study was to assess the impact of a pharmacologically induced cortisol increase during the non-stressful friendly TSST on long-term memory for details presented during this event. In a double-blind between-group design, participants (final sample: 20 men and 13 women) either received hydrocortisone (20 mg) or a placebo and were then exposed to a non-stressful social interaction (fTSST). Affect, salivary cortisol, and salivary alpha-amylase (sAA) were assessed before and after the fTSST. Recognition memory for objects presented during this situation was assessed 1 day later. Positive affect and sAA increased in response to the friendly TSST in both groups. Hydrocortisone enhanced memory for peripheral objects of the situation in men but not in women. Memory for central objects was not affected by the hormone. The results suggest that in a non-stressful positive social environment, cortisol induces a broadening rather than a narrowing of memory. In addition, the findings provide preliminary evidence that this effect might be more prominent in men.