Effects of Stress on Memory

Stress, emotions and memory

When having high stress hormone levels is good for you…

Normal everyday memory performance is very different than memorizing a very arousing or traumatic event, such as a car accident. Stress hormones have the capacity to increase your memory for traumatic events because they exist in large part to help you survive (e.g. chase a mammoth). By having a vivid memory of the highly arousing or traumatic event you will likely act in a way to avoid similar encounters in the future.


Think back and recall who you were with and what you were doing on the morning of May 14th 2005. Go ahead, you can laugh!

Now, recall who you were with and what you were doing when you learned of the events of September 11th 2001? You likely answered this question in full detail. Despite the fact that September 2001 was 4 years before May 2005, you had an easier time remembering events that took place much further back in time....Why?

Because emotionally charged events are better remembered than are neutral events.

Our ability to remember something is directly linked to how much attention is devoted it. If you do not pay attention to what you are reading right now, there are few chances that your brain will be able to memorize it.

What we now know is that the emotional significance or valence of an event helps to determine how much attention we pay to it. Events such as September 11th command our attention because this information is detected by the brain as being threatening, so the brain directs all its attention to it.  More attention equals more memory because all the brain’s power is used to encode this event. Researchers describe this as the Flashbulb Memory Phenomenon in which the details are literally burned into our memory.




Threat to the Ego

Sense of control              

If you think back to our mammoth hunting days, this makes sense. If you narrowly escaped a saber tooth tiger attack, then it would be critical for you to remember the important details that ultimately ensured your survival (what territory you were in, how you escaped etc). Stress hormones like adrenaline and cortisol work together to help you along in this process. By increasing your memory of threatening events, they ensure that you will survive.

The link between stress hormones and memory

In highly charged emotional situations, the stress hormones released travel to our brain and take seat in areas that are important for memory. This helps us to focus on central or key elements of the situation and as a result we tend to let the peripheral details that are not relevant slide. e.g. the colour of your friend’s sweater the day of the September 11th attacks.

In the same vein, there is something known as the weapon’s focus phenomenon. People, who have been mugged at gun-point for instance, can often describe their attacker’s gun in detail but are hard pressed to say what he/she looked like.  After all, the gun is what posed the immediate threat, not the attacker’s eye colour!

Desperate to forget

There are times however, when the memory enhancing effects of stress hormones can be too efficient and result in memories that will just not go away. In Post-Traumatic Stress Disorder (PTSD), individuals exposed to trauma are often plagued with intrusive memories of the event that they relive over and over. Researchers are now trying to see if giving drugs that prevent stress hormones from enhancing emotional memory would be effective in decreasing the probability of developing PTSD.

So good to remember

There is always a silver lining to any situation and the effects of stress hormones on memory are no exception to this. The beauty of our stress response system is that it also releases stress hormones when we experience positive emotions. As such, you will likely never forget the look on your child’s face when they saw their first birthday cake; you probably have vivid memories of receiving the shiny red bicycle you always wanted as a child or the proud look on your parent’s face when you walked across the stage to get your diploma.

Take home message
Where stress hormones and emotional memory are concerned, again, it is a matter of balance as such, too much of a good thing can be bad. We are equipped with a system that makes it is easy for us to remember things of emotional significance be they good or bad. Stress and stress hormones can often be good for memory function. So why is it that I forget things when I am stressed?