Depends on the rider's level of ability plus their capability to mentally absorb information.
In the early 70's, Jarno (as a Privateer) could go to a track for the first time......do one scouting lap.....and then break the track record.
In the 60's, Mike could turn up to a meeting after a skinful the night before, not even know what he was riding (he didn't know one end of a spanner from the other) and he'd just say "Which way does the track go and what's the lap record?" And he'd wipe the floor with everybody.
Those guys had other worldly levels of ability admittedly, but it just goes to show that everybody is different.