Crisis Stress: Part 4 – Concentration, Memory, and Focus
In the first three parts of this short four-part essay series, I briefly summarized some of the ways in which a crisis affects people in terms of physiological reactions including the Acute Stress Response (ASR) and some (but not all) of the various psychological and cognitive effects of such stress on crisis mangers and their performance. In this fourth and final essay in this series, I will cover some of the recent research on diminished memory and recall abilities rising from acute stress factors during crises.
Acute crisis stress affects many memory functions and other cognitive functioning of the brain. There are different levels of stress and the high levels can be intrinsic or extrinsic. Acute stress is a stressor that arises from an immediate perceived threat. The research on the effects of acute crisis stress on human memory and recall paints a complex portrait that resists simple descriptions. The main line of research findings suggests that acute crisis stress can impair both short and long-term memory, and one’s ability to recall even well-rehearsed skills, abilities and behaviors, as well as the formation of new memories that would have expected to have formed during crisis contexts. While other studies have to the contrary suggested instances where acute stress can enhance memory both in terms of recall and the formation of new memories during peak periods of acute stress. It is useful to remind ourselves that different people experience acute stress differently and not all of us react to experienced stress the same way as others even when we do experience it. It is possible that uncertain certain circumstances and for certain people that acute stress might function to suppress memories and either aid or hinder the formation of new memories.
Working memory is the ability to temporarily store information to manipulate it for performing complex tasks, such as reasoning or decision making. Working memory is affected by acute crisis stress. However, studies on stress has been shown to both improve and impair working memory. Changes in working memory reaction time, an increase in false alarms and mistakes, and faster information processing have all been findings from the research on acute crisis stress and working memory. On the other hand, anxiety has been found to be disruptive to working memory capacity and loading.
Acute Stress Response (ASR) and Memory
Anecdotal testimony about acute crisis stress and memory formation is contradictory. Stressful, aversive events are extremely well remembered, or people seem unable to recall the experience or any specific aspect of it. Scientific research has also produced mixed findings. For example, research on post-traumatic stress provides support pointing to the deep-rooted formation of indelible (unforgettable) memories during acute stress contexts. If acute stress does serve to enhance memory formation that would suggest that the ability for forming memories is evidently beneficial for survival, but the very same mechanism may become maladaptive and lead to posttraumatic stress disorders (PTSD). The less than fully satisfying conclusion is that crisis stress can have impairing, enhancing, or absolutely no influence on memory systems, recall, or new memory formation.
ASR-released hormones are known to enhance post-learning consolidation of aversive memories but are also thought to have immediate effects on attentional, sensory, and mnemonic processes at memory formation. The effects of acute stress on memory include possible interference with a person’s capacity to encode memory and the ability to retrieve or recall previously remembered information. During times of high stress, the body reacts by secreting various stress hormones into the bloodstream. Over-secretion of stress hormones may impair long-term delayed recall memory, but can enhance short-term, immediate recall memory. This aspect is particularly relative in emotional memory. The hippocampus, prefrontal cortex and the amygdala are affected. One class of stress hormone responsible for negatively affecting long-term, delayed recall memory is the glucocorticoids (GCs), the most notable of which is cortisol. Glucocorticoids facilitate and impair the actions of stress in the brain memory process. Under routine circumstances, the hippocampus regulates the production of cortisol through negative feedback because it has many receptors that are sensitive to these stress hormones. However, an excess of cortisol can impair the ability of the hippocampus to both encode and recall memories. These stress hormones are also hindering the hippocampus from receiving enough energy by diverting glucose levels to surrounding muscles.
Memory Retrieval and the Formation of New Memories During Crises
Acute stress can also affect a person’s neural correlates which may interfere with the memory formation. During a stressful time, a person’s attention and emotional state may be affected, which could hinder the ability to focus while processing experiences. However, there is a widely accepted construct that assumes that acute stress with incidents that are negative (bad or traumatic experiences) are retained as memories and that these memories are long-lasting and persistent.
Stress can also enhance the neural state of memory formation. Several studies have suggested that acute stress, the Acute Stress Response (ASR) and glucocorticoids, which are released as part of the ASR, may work generally to enhance new memory formation while they simultaneously impair memory retrieval. This might be the case if the brain regions involved in the retrieval of the memory correspond to the regions targeted by glucocorticoids. Further, there may also be differences in the type of information which is either being remembered or being forgotten while being exposed to acute stress. There is some contradictory research on this question to be found in the literature review. One study found that in some cases neutral stimuli tended to be remembered, but salient (emotional) stimuli tended to not be remembered during crisis stress contexts. In other studies, however, the opposite result was observed (neutral information was not remembered, and emotional information was remembered in crisis contexts).
The importance and relevance of the information to the individual may also be a variable as to whether the event information is to be remembered. If stressful context event information is salient and valent to a person, the event information is more prone to be stored in permanent memory.
It is also possible that an important factor in determining what will be remembered and what will be forgotten is the timing of the perceived stressful exposure and the timing of the retrieval. For emotionally salient information to be remembered, the perceived stress must be induced before encoding, and retrieval must follow shortly afterwards. In contrast, for emotionally-charged stimuli to be forgotten, the stressful exposure must be after encoding, and retrieval must follow a longer delay.
Acute stress appears to impair the accuracy of autobiographical-experienced memories. After exposure to an emotional and stressful negative event, personal flashback memories can occur. Aspects of autobiographical memory, episodic memory, the memory system regarding specific events, and semantic memory, the memory system regarding general information about the world, are all impaired by an event that induces a stressful response. This causes the recall of an experience of a specific event and the information about the event to be recalled less accurately.
The major effect of acute crisis stress on memory recall is that it may improve consolidation of memory, while it also impairs the retrieval of memory. In other words, while one may be able to remember event information (quite significantly if it is negative salience information) relating to a stressful situation afterwards, while during a stressful situation it is difficult for some to recall specific previously remembered information.
Malleability of Memory
One final aspect about memory as we consider acute crisis stress is the malleability of memory. Recent studies (including those investigating the unreliability of eyewitness testimony) have found that it is feasible and not all that difficult to implant “false” memories in people and have them recall those as if they were real and true memories. Further, recent gerontological research findings suggest that the tendency for the human brain to generate false memories on their own to “fill in the gaps” of remembered experiences may increase as we age (our brains are trying to be helpful).
The idea that an acute high stress crisis would affect our ability to retrieve memories, use our working memory, and affect our ability to form (or forget) new memories is quite easy to grasp. What we choose to do with knowledge of this human factor vulnerability is up to us.
Conclusion for the Four-Part Essay Series
During disasters and emergencies, people are affected by the stresses and challenges of events. These events can sometimes be quite traumatic. For those who are enduring and surviving during a high-stress situation, we should be attentive to the ways in which such events affect them and change them. In addition to recognizing and adapting to those with whom we work or manage (who are under tremendous pressures during crises) we as crisis managers are likewise affected by the stresses of these events. Even emergency responders and crisis managers who are usually well-trained professionals with specialized technical and professional knowledge appropriate to deal with a wide range of emergencies, dangers, and disasters can be significantly impacted by crisis events and high-pressure situations.
We must be aware of these human factors and adapt to them to perform effectively during crises.