I recently came to realise that my memories of my experiences of early childhood are probably greatly affected by seeing my younger siblings going through those same experiences a few years later. At age five or six I would see my mother reading to them on the sofa and they would be lying with their heads on her tummy feeling her warmth and listening to her heartbeat and stomach gurgles. Seeing this would remind me of when I used to do that, thus reinforcing those memories and probably somewhat distorting them. One of the distortions is that this memory is set in the house we moved to when I was four, and most of my own relevant experiences would have been set in our previous house. I think the accumulation of memories is a bit like training an LLM on a combination of new data and its own data.