Freud was not always consistent with the words he used for processes at different times in his career. The mechanism described above is usually called suppression and not repression, but like in the article above you may occasionally find suppression also termed repression in a broader sense.

That the conscious effort to avoid unpleasant memories (supression) is possible, has never much been disputed. Imagine you have lost a child, every good friend tells you after some weeks you must stop thinking of the child at a daily basis. And you'll be happier in the long run if you avoid thoughts of your loss. But you'll never respond that you did not have a child at all when directly asked. However, if you avoid thoughts of your dead child you'll find it increasingly more difficult to have access to detailed memories. The fine article above is about this memory mechanism.

Repression in the narrow sense happens if after a loss of a child you'll deny you ever had a child even at a direct question and you believe what you are saying is true. In Freud's sense this happens completely unconscious and even unavoidable to you. Whether such a process happens is much disputed. The usual pattern for survivors of a catastrophic life event (loss of a child, inmate in a concentration camp,...) is that these persons cannot forget despite all their efforts.

Both suppression and repression together are sometimes losely termed repression which is unfortunate since (1) they are probably completely different processes, (2) one of them is undisputed and the other much disputed and (3) lay persons may be misled by the not well considered application of terms.

Wolfgang