Effects of Stress on Memory

Test the effects of stress on your memory

This graph represents our prediction of your pattern of results.


Why were we able to predict your results, without knowing your scores?  Because scientific studies of memory function in humans have shown us that when you divide your attention between two tasks, your brain finds it hard to encode everything at the same time.

With the simple task, you were only asking your brain to read and remember one thing at a time. But as you went on with the tapping, your brain had to do multiple things at once. As you can see, the number of words you recalled decreased with more distractions. If it didn’t well then bravo!

In fact, you were dividing your attention which likely interfered with your ability to pay attention to what was relevant; the words. As a result, fewer words entered your short-term memory because the tapping and blablaing interfered with the encoding of the words.


Your memory may in fact be excellent, but when your attention is divided between 3 or 4 things, your memory system can ‘crash’. Stress does not even have to be in the picture for your memory abilities to decrease!

Brain Drain

The degree to which your memory will suffer is also highly related to the nature of what you are doing. The BLA BLA BLA task was the hardest because we asked you to read, learn words, and make sounds all of which are verbal in nature. This is mentally draining!

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If you are at the office and are reading emails and the phone rings stop reading, pick up your note pad and pen, and listen to what the caller has to say, otherwise you are dipping into the same resource pool and will come up dry in the end! How can I improve my memory?

Think of your brain and its different resources (e.g. verbal or motor) as a series of swimming pools. Every time you place a demand on a resource system, you are draining water out of the pools. Even though the brain has many pools, they do not contain much water. By tapping into the same resource pools at the same time you will literally cause a brain drain!


Keep this in mind the next time you are driving.

You are driving (motor), your cell phone rings and you reach to answer (more motor), you start talking (verbal), the radio is too loud (verbal) so you turn it down (even more motor), and all the while you are keeping an eye on the exit signs to get off the highway (more verbal and visual). How much water do you think is left in the pools? Some of what the caller said may not make into your memory and stress had nothing to do with it!

In reality, you do not even need to be stressed to have difficulties remembering things. The mere act of draining water from the same resource pools can be enough. Adding stress just empties the pools faster.


Internal Interference from Stress

A final important point is that interference from stress is not always from an external source, we actually do a pretty good job at interfering with our own memory’s with stuff going on in our head’s!

For instance, at lunch you catch two co-workers talking behind your back and this causes you some emotional distress.

If you are like many people, you replay the moment in your head. Then your boss comes to your office with an unforeseen request. BINGO, the stressful nature of the experience at lunch (unpredictable, threatens your self-image or ego and perhaps leaves you with a poor sense of control) and the stress hormones released as a result might prevent you from giving your full attention to the request and important details. Here, stress has interfered with encoding.

Don't go n.u.t.s. over stress



Threat to the ego

Sense of Control

THE recipe for stress

Now say that your boss came in, gave you the information needed to complete the request. While you were consolidating this information the events of lunch pop into your mind. This intrusion by the stressful situation could disrupt the consolidation process.

Finally, you have consolidated the information but the next day you are in a meeting with the individuals who were talking behind your back. You relive the stressful event in your head and just at that moment, your boss asks you to share the information given yesterday. You choke, get flustered, and simply cannot remember. The stress you are feeling interfered with your ability to retrieve/recall the information you had clearly consolidated.

Take home message
Dividing your attention can be enough to prevent you from detecting and paying attention to the relevant information. If you add stress, then your ability to detect what is relevant is compromised because it acts as a form of interference that prevents you from: (1) Paying attention (2) Determining what is relevant (3) Paying attention to what is relevant and ultimately encoding it. You cannot forget something you have not encoded in the first place! Each stage of memory is vulnerable to stress (i.e. consolidation and retrieval) and importantly, stress is not always an external influence on memory, what goes on in our mind can be a very potent source of stress interference.