Effects of Stress on Memory

Is your memory affected by stress?


How Stress Affects Memory?

How exactly does stress interfere with memory? To answer this question we first need to understand how memory works. You may find that stress has nothing to do with you forgetting!

Memory processing allows us to acquire, retain, and recall information and/or experiences. We have short-term memory and long-term memory. Information is first in our short-term memory (also called working memory) and it then gets processed and stored into our long-term memory. How?

Tips

You can think of the three stages of memory processing in the following way: encoding is like listening to songs, consolidation is like recording those songs (or burning a CD), and retrieval is like playing back the songs.

Information makes its way into memory by way of three stage:

1. Encoding is receiving information from the environment and preparing it to become a memory e.g. someone tells you a phone number.

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2. Consolidation is how information becomes fixed into our long-term memory. e.g. you work the information by repeating the number in your head.  Consolidating a memory is like burning a CD.  Once the CD is burnt, it is in your long-term memory store.

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3.Retrieval is calling back the information stored in long-term memory when we need to use it e.g. bringing the number to mind and dialing it the next day.

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Stress can interfere with each of these stages of memory processing.

Interfere with the memory

When we encode information, we usually have many methods that we use to ensure that this information will start to be consolidated.  Most of the time however, we simply repeat the information in our head in order to memorize it.  If I give you the phone number 761-6131 and asks you to go and dial it on the pay phone at the end of the corridor, there is a good chance that on your way to the payphone, you will repeat this number over and over again until you can dial it.  By doing this, you are ensuring that the memory trace of the phone number stays active in your short-term memory.

REMEMBER

You cannot forget what you never encoded in the first place! However, information can be in your long-term memory store, but this does not mean that it is safe! Stress can also interfere with your capacity to retrieve this information from your long-term memory store.


Although this system works quite well most of the time, the caveat is that this system is very sensitive to interference.  For example, if, while walking toward the payphone to dial the number, you meet your friend Sarah in the corridor who starts talking to you, then there is a very high probability that you will forget in an instant the phone number that you were repeating over and over again!

Stress is like Sarah showing up before you can encode the number; it is a form of inteference. When you are stressed by something (e.g. work, a colleague etc.) this stress takes a lot of resources from your brain and interferes with your capacity to encode any new information.  This is when you will ‘forget’ the management’ meeting, or to bring your child to the dentist. Did you really forget these events? OR did these events even make their way into your memory in the first place i.e. were they encoded?

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There is a fair chance that you never encoded this information in the first place.  At the time that your colleague told you that ‘Next Thursday, there is the management meeting’, you did not pay full attention to what this person said because your brain was occupied with a stressor.  Consequently, the management committee information never made it to your brain, was not consolidated and never entered your long-term memory store.

Did you know?

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). 

For example, the phone number that you had to dial on the payphone at the end of the corridor could now be in your long-term memory store, and you now know this phone number ‘by heart’.  However, it is quite possible that the next day, just as you are about to dial it, Steve asks you a question. You then look at the phone and you draw a blank. Stress can act in the same way and prevent us from retrieving information from our memory. 
 
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Take home message
Memory processing involves many steps each of which is relatively easy to disrupt. Stress primarily acts as a source of interference and can prevent each of the stages of memory processing (encoding, consolidation, and retrieval) from occurring. So, why do I really forget things when I am stressed?