Once upon a time, three groups of subjects were asked how much they would pay to save 2,000 / 20,000 / 200,000 migrating birds from drowning in uncovered oil ponds. The groups respectively answered $80, $78, and $88.1
(or extension neglect) We can concretely imagine only up till maybe five. Than it's start quickly fading. We cannot really imagine numbers larger than 15. The larger the number the larger scope neglect will be. It extend also on so called extension neglect. We cannot comprehend big chunks of time, of amount of people, of how much some specific thing relates to the larger whole etc.
Example: in a document Shoa, a Nazi director of a concentration camp, when asked how many people were in killed in his camp, answered: "40,000 or 400,000"