Count the "f"s in this passage
How many did you count?
There are actually 6 “f”s, but most people only count 3. Why? It seems that the brain has trouble correctly processing the word of. The letter “f” usually makes the /f/ sound, like in fox. In the word of, though, it makes the /v/ sound. As a result, the brain overlooks the word of as it scans for the sound of /f/.