Toggle Function Keys

The keys at the top of your Mac keyboard are both function keys (F1 to F12 or F19) and special feature keys: brightness, expose, volume, etc. You can decide what they do by default in System Preferences, Keyboard. Check or uncheck “Use all F1, F2, etc. keys as standard function keys.” Then, look for the “fn” key on your keyboard. This toggles those keys the other way. So if you choose to use them as F-keys, then holding “fn” will make them work as special feature keys. The main reason to use these as F-keys is if you use software that utilizes them, like many Adobe applications do.