[nightpool]

Actually, it's almost entirely the opposite—the idea that students are a "sponge" that can soak up knowledge perfectly is then taken directly to mean that some students are better at soaking up / retaining knowledge then others, and that the "smart" kids who do the best on the tests are the ones who are going to retain the knowledge the best. And then the ones that were the best knowledge-sponges will eventually go on to become the next generation of teachers, since they know the most information. Whereas for most kids it's completely the opposite—they memorize the information in their short-term memory without understanding the fundamentals, they do great on the tests, and then they forget all of it immediately. But they stand out from their peers as better students, because they're able to play the "game" of school better and optimize for being a knowledge-sponge that will absorb the most information as possible and forget it as quickly as possible.