Richer's Ghost
Bourbonite
I bet if 10 of us did the same game we would have as much as 20% difference in our totals.
The definition is not arbitrary at all. Of course it's going to very depending on what the person actually sees as I mentioned in my suggestion to have everyone count the same game and laugh at the results. Just like eyewitness testimony being nearly worthless in investigations because the brain tricks people into seeing things they didn't really see.