I assume everybody here is familiar with the feeling when you suddenly understand something; it&#x27;s as if pieces of a puzzle suddenly click together and create the whole picture. So, my question, what is this feeling? How does the brain recognize that it should have this feeling? (Because we can feel it in so many abstract things...) Maybe curiosity then can be just explained as a craving for this feeling; but actual cognitive basis behind this feeling, at least to me, seems lot more interesting.