According to a study published in Behavioral Neuroscience in 2010, the ability to retrieve social information from memory can be impaired by a brief exposure to stress.
The study was conducted by Christian J. Merz, Oliver T. Wolf, and Jurgen Hennig.
Previous research has found that being exposed to stress can aid in the creation of new memories, which is one of the reasons why negative memories can often be harder to forget than positive memories.
In Merz and his colleagues study, 29 participants learned the details of two biographical notes and were then exposed to a stressful situation by having to give an impromptu speech for five minutes in front of a camera, which they were told was being broadcast to a live audience.
After being exposed to this stressful event, the participant’s social memory was tested and compared with a control group. The participant’s level of stress was assessed by measuring the amount of the “stress hormone” cortisol in their saliva.
As the amount of cortisol increased, the ability of the participant to recollect and recognize information from the biographical notes that he or she had learned previously decreased.
In other words, increased stress caused a decreased ability to retrieve social information from memory. The more stress the participant had experienced, the harder it was to retrieve information from memory.
The effect of stress on memory may be due to the way that cortisol effects the hippocampus, a region of the brain that is associated with memory. The hippocampus is known to have a high level of glucocorticoid receptors, which are sensitive to hormones such as cortisol.
“The relevance of impair social memory retrieval after stress is obvious in daily experiences such as partnership conflicts,” notes Merz and his colleagues. “These effects become even more important during courtroom testimony or similarly important stressful retrieval conditions.”
Merz, C.J., Wolf, O.T. & Hennig, J. (2010). Stress impairs retrieval of socially relevant information. Behavioral Neuroscience, Vol. 124, No. 2: 288-293.