Researchers have shown that a biological mechanism exists in the human brain to block unwanted memories. The findings reinforce Freud's thesis about the existence of memory suppression.
The experiment showed that people are capable of repeatedly blocking thoughts of experiences they don't want to remember until they can no longer retrieve the memory, even if they want to.
Controlling unwanted memories was associated with increased activation of the left and right frontal cortex which led to reduced activation of the hippocampus (the part of the brain used to remember experiences).
The more subjects activated their frontal cortex during the experiment, the better they were at suppressing unwanted memories.
The Freudian idea is that even though someoe is able to block an unpleasant memory it they has consequences even though he doesn't know why. Sound familiar?
I made myself a promise, that I'd soon forget we ever met, Well, but something sure is wrong, 'cause I'm so blue and lonely. I forgot to remember to forget.