We’ve probably all experienced those moments where too many things compete for our attention and something has to give. You’re running late, you get to the car only to find you’ve forgotten the keys. Just a few days ago the British Prime Minister, David Cameron, arrived home after a Sunday lunch with friends and family and discovered to his horror that he’d left his eight-year-old daughter behind. A number of parents were quick to point out that they’d had similar experiences having left their own child in a taxi, on a train, or maybe in some cafÃ©.
So, forgetfulness is a fact of life. The causes and extent of forgetfulness may vary from fatigue to problems in the way we encode, store and retrieve information, competition for our attention, through to organic reasons such as trauma, or diseases like dementia. We generally accept our forgetfulness as a human flaw, but there are times when people begin to notice they’ve become more forgetful than usual and this gives rise to concerns.
Chronic stress is a well-known cause of forgetfulness and researchers believe they understand at least part of the mechanism behind this. An area of the brain called the prefrontal cortex is responsible for, amongst other things, working memory, attention, judgment and decision-making. It takes just a few days of exposure to stress hormones like cortisol before the negative effects of stress on these processes begin to show.
Professor of Psychiatry and Psychology, John W. Newcomer, M.D., asked volunteers to take a substance that mimicked the effects of cortisol over a four day period. Volunteers were asked to recall certain parts of a paragraph in order that a component of memory (known as verbal declarative memory) involving particular regions of the brain could be tested. The results were then compared with volunteers who took a lower dose and those who took none. Only those who were exposed to higher levels of the cortisol substitute showed forgetfulness.
Exactly what does this experiment tell us? According to Newcomer, the amount of stress required to produce such an effect far exceeds a typical bad week at work, for example. He likened the experimental effect to that of a major trauma such as abdominal surgery. Even so, he says, the cumulative effect of stress over a period of time could well explain why many chronic stress sufferers appear to have problems with their memory.
And what about everyday activities? Professor Newcomer concedes that some people may well experience high levels of cortisol in response to other forms of psychological stress. The pressure of upcoming final exams could be an example. He says, "Mom and Dad may have been right when they told us cramming for exams is not a good idea."
The good news is that it after a week on the cortisol-memory experiment the memory impairments shown by volunteers were reversed.
Washington University School Of Medicine (1999, June 17). High Stress Hormone Levels Impair Memory. ScienceDaily. Retrieved June 25, 2012, from http://www.sciencedaily.com /releases/1999/06/990617072302.htm