It’s similar to when I lose my keys. I’ve found that the most effective way to locate them is to forget that I’ve lost them. Their whereabouts will come back to me when I stop trying to remember. But sometimes I don’t have the time to forget. Sometimes, I need to find them immediately. In such situations, I replay the events of the previous day, trying to decipher where I put the goddamn things. But whilst doing so, I also raise questions and plant information that is false and contradictory. “Did I put them on the kitchen counter?” “The last time I saw them they were in the dining room.” Were they? Is that what really happened? How do I know I’m not deceiving myself? I don’t, and that’s the problem.
But while there’s not many ways to separate out true recollection from imagined memory, there is a heuristic: if recollection is forced, the human mind will provide more false data, more noise. It’s a natural, inherent ability of ours; given any two points, we can find a connection, we can create a path. The converse side of the heuristic: recollection that is unforced provides less false data, less noise. When I walk through a building and smell that aroma, scenes from my past come flashing back. Those scenes I recall will be more true to life than those I could summon by sitting in some sterile environment and forcing myself to bring them back to surface.
Perhaps the easiest way to understand this is to think in terms of ratios: a forced recollection contains more signal for every speck of noise. An unbidden recollection is the reverse.