People can remember things that hadn’t re-entered their mind for decades. It certainly happened to me a number of times (completely trauma-unrelated and not actively elicited).
The idea of "repressed memories" was that people had hidden memories that they couldn't access, even if they tried. According to the theory, even if someone brought up the past event and tried to remind the person about it, they would be unable to recall it happening because their brain had blocked it out.
The idea was that only intervention by a therapist or some other special event could help the person "unlock" the repressed memories, making them available for remembering again.
What was really happening was that some therapists were leading people into "remembering" things that didn't happen through aggressive prompting and pushing, much like what happens when an aggressive investigator convinces a vulnerable person to falsely confess to something they didn't do.
Other things about that day were surfaced. How my braces felt and the fear I felt about forgetting a textbook.
All real, but unsurfaced until then.
If you hear the first tones or words of a song you're much more likely to be able to tell the lyrics that follow compared to being asked to say those lyrics based on the title.
It is specifically about trauma, and generally you don't forget traumatic events and that's often a big part of the problem. We are not talking about trivial things like the name of your maths teacher in high school, which have a tendency to come and go.
It is also specifically about therapy, that is an environment where you are actively encouraged to recall memories. We know how easy it is to make up memories, especially with the help of a third party (here, the therapist).
Combine the two: memories that are hard to forget and an environment conductive to making false memories and it becomes very likely that the "lost" memories are completely made up.
That depends on how many you endured really. Only so much room in the old noggin with everything else important going on.
Oh, of course you can.
Some of the techniques included hypnosis or even giving the patients (including children) sedative-hypnotic drugs before pressuring them with the leading questions.
If they could eventually get the person or child to claim to have some memory of the event (after asking a lot of leading questions and maybe even drugging them) they considered it to be a recovery of the memory.
On top of that, I have legitimate memories that were not traumatic, but still related to the same traumas because said person attempted to encourage these activities throughout my young life on rare occasions. I didn't remember what happened as a kid, but I knew something wasn't right and I wasn't comfortable. It wasn't until I was almost 30 that I had my first "flashback" which was a fractured memory, I still remember it looked like a faded photograph in my mind, and it was accompanied by an extremely uncomfortable feeling.
The re-surfacing memories aren't real in a sense, but in my case they aren't entirely fake either.
I wonder if it's possible that things can be completely imagined with absolutely no basis what-so-ever in certain circumstances, and I also wonder how difficult it is to discern that. It seems to be a difficult concept to manage.
On the other hand, I do have some Gandalf "I have no memory of this place" moments for other things.
Though you're right - a specific scent can easily call up an ancient, forgotten memory.