Our minds build up defenses when we are hurt that allows us to block out events that cause us pain. Some of these memories are consciously suppressed, until a time when we feel we are strong enough to pull them back into our conscious, while others are unconsciously repressed, or even disassociated, so they can only be pulled back through deep psychoanalysis.
When we suffer some kind of tragic event — such as the death of a loved one or the break up of a long relationship, we often consciously push thoughts that may remind us of that person out of our minds and bury them deep in our subconscious. A suppressed memory can be brought back through a conscious effort to do so, as we placed it in storage on a conscious level in the first place. Repressed or disassociated memories are not so easy to retrieve.
In 1892, Sigmund Freud, himself a trained neurologist, proposed that suppressed memories are a “voluntary form of pushing painful and anxiety-provoking thoughts, memories, emotions, fantasies and desires out of awareness.”
Say you and your spouse were having a wonderful vacation in the Bahamas and everything seemed to be going beautifully when he/she went swimming and was attacked by a sting ray and died suddenly. You are in shock and pain as you make the arrangements to return home and contact family and friends. You are in a daze throughout the funeral and for weeks afterward, going through the motions of living and trying not to think about your loss. You have suppressed all memory of the vacation and what happened afterward, and stored them for future reference when you are strong enough to deal with them. You even consciously avoid going through closets and personal belongings in order not to have to deal with the pain that is still fresh. This is suppression, your brain’s conscious effort to put aside for safe keeping memories that are too hard to deal with.
Science is able, through the advances in technology (including the MRI and fMRI machines), to directly measure brain activity. They are able to look into how our brains are able to take traumatic events and build up defenses that include suppression, repression and even disassociation of these memories. Whereby scientists believed that suppressed memories were simply a psychoanalytical myth with no scientific support, data obtained from fMRI scans now can indicate otherwise.
Researchers at St. Andrews University in Scotland, explored the brain basis of memory suppression through a study called “think/no-think.” Twenty-four volunteers had to memorize 48 word pairs (for example, ordeal-roach or steam-train). While they were lying in a fMRI scanner. Each was shown the first cue word and had to either recall the second, associated word (called the respond condition) or prevent it from entering consciousness (suppress condition). “Actively suppressing the matched word while lying in the scanner had the effect of reducing recall of the word afterward (as compared with the respond condition), said Psychologist Michael C. Anderson, the lead on the study. “The result was not just simple forgetting that occurred with the passage of time,” he said.
The imaging data that Anderson and his colleagues collected found that the volunteers suppressed the words by recruiting parts of the brain involved in “executive control,” namely, areas in the prefrontal cortex, to disengage processing in sectors of the brain important for memory formation and retrieval, in particular the hippocampus.
Noteworthy from this study as opposed to earlier experiments was the amount of activity in the hippocampus is proportional to memory recall–the stronger the activity, the higher the likelihood of remembering. Secondly, the researchers found that the brain is more active when avoiding the recall of a memory than during the recall itself. People suppress unwanted memories by exerting willful effort that can be tracked in the nervous system.
This is Ron White, two-time USA Memory Champion
Scientific American — Defense Mechanisms: Neuroscience meets Psychoanalysis: http://www.scientificamerican.com/article.cfm?id=neuroscience-meets-psychoanalysis