Facts that change neither too quickly nor too slowly, so we have difficulties to notice their change, are called mesofacts. There is a nice article in Boston Globe about them. And here is the analogy for mesofacts

For these kinds of facts, the analogy of how to boil a frog is apt: Change the temperature quickly, and the frog jumps out of the pot. But slowly increase the temperature, and the frog doesn’t realize that things are getting warmer, until it’s been boiled. So, too, is it with humans and how we process information. We recognize rapid change, whether it’s as simple as a fast-moving object or living with the knowledge that humans have walked on the moon. But anything short of large-scale rapid change is often ignored. This is the reason we continue to write the wrong year during the first days of January.