Gaining knowledge mediates changes in perception (without differences in attention): A case for perceptual learning.

Firestone & Scholl (F&S) assert that perceptual learning is not a top-down effect, because experience-mediated changes arise from familiarity with the features of the object through simple repetition and not knowledge about the environment. Emberson and Amso (2012) provide a clear example of perceptual learning that bypasses the authors' "pitfalls" and in which knowledge, not repeated experience, results in changes in perception.