A number of studies have examined how stress affects learning and memory, but the literature has shown mixed results.
Joëls and colleagues (2006) have summed up the results. In fact, stress may enhance learning and memory processes, but only as long as the stress hormones are experienced in the context and around the time of “the event” that needs to be remembered.
The release of stress hormones, particularly corticosteroids, may result in a learning experience by focusing attention and improving memory of relevant over irrelevant information. So how do stress hormones affect the brain?
“It has been found that both noradrenaline and CRH [corticotropin releasing hormone] strengthen synaptic contacts in the hippocampus.”
The hippocampus has been associated with learning and memory processes (Deng et al., 2010), and stress hormones strengthen synaptic contact in this region of the brain.
The initial release of stress hormones enhances learning if it is experienced in the context of learning, but the normalization of stress levels seems to be just as crucial for learning processes.
So stress hormones need to be normalized (to a moderate level) before or after a learning task in order to enhance learning, otherwise they just impair it.