Why Do We Remember Stressful Experiences Better?

Summary: Memories of objects from stressful situations rely on similar neural activity to memories of the stressful events themselves.

Source: Current Biology.

Stressful experiences are generally remembered more easily than neutral experiences. Researchers at Ruhr-Universität Bochum (RUB) have analysed the reasons for this cause. They conducted an experiment where they put participants in stressful situations during simulated job interviews and then recorded their memory of objects from these interviews.

Using functional magnetic resonance imaging, they measured brain activity while the participants saw the objects again. Memories of objects from stressful situations appear to depend on similar brain activity as memories of the stress trigger itself.

Unlike in many previous laboratory studies, the researchers decided to record the memory trace of an actual event in their experiments, using the so-called Trier Social Stress Test for this purpose. This test requires the participants to speak in front of an application committee, all of whom display a neutral expression and do not give any positive feedback. The test is designed to trigger stress in the participants.

During the job interview simulation, the committee used a number of everyday objects; for instance, one of the committee members took a sip from a coffee cup. The control group was approached with the same objects, but the participants were not subjected to any stress.

After one day, the researchers showed the objects to subjects in both groups while recording brain activity in a magnetic resonance imaging scanner. The participants who were put under stress remembered the objects better than members of the control group.

The researchers analysed the brain activity in the amygdala particularly. It is a region whose main functions include emotional learning.

The researchers found that the memory traces of objects that had been used resembled each other more closely than those of objects that had not been used. For the subjects in the control group this was not the case. In other words, the brain representations of the objects from the stressful situations were very closely linked, and they were thus clearly distinct from other experiences and we’re remembered vividly.