But how many six-year-olds would succeed at memorizing every event in their their life if they ever decided to do so? Since there wasn't any environmental stimu

But how many six-year-olds would succeed at memorizing every event in their their life if they ever decided to do so? Since there wasn't any environmental stimulus for them to do so I suspect a genetic reason for their ability. They also never mentioned that they somehow decided to spend a lot of time cataloging their memories. It seems to be totally effortless for them.