Returning briefly to the dynamics of memory, this may be of interest from the current edition of Nature magazine, which can be found on-line at this site (although it requires a free registration for reading abstracts like this one).

Suppressing unwanted memories by executive control

MICHAEL C. ANDERSON AND COLLIN GREEN

Freud proposed that unwanted memories can be forgotten by pushing them into the
unconscious, a process called repression. The existence of repression has remained
controversial for more than a century, in part because of its strong coupling with trauma,
and the ethical and practical difficulties of studying such processes in controlled
experiments. However, behavioural and neurobiological research on memory and
attention shows that people have executive control processes directed at minimizing
perceptual distraction, overcoming interference during short and long-term memory tasks
and stopping strong habitual responses to stimuli. Here we show that these mechanisms
can be recruited to prevent unwanted declarative memories from entering awareness, and
that this cognitive act has enduring consequences for the rejected memories. When people
encounter cues that remind them of an unwanted memory and they consistently try to
prevent awareness of it, the later recall of the rejected memory becomes more difficult.
The forgetting increases with the number of times the memory is avoided, resists
incentives for accurate recall and is caused by processes that suppress the memory itself.
These results show that executive control processes not uniquely tied to trauma may
provide a viable model for repression.

Regards,

A