Pinch to zoom not working on safari

I have a 2012 macbook pro running mountain lion. when im on safari, my pinch to zoom gesture doesnt work. i can double tap and it will zoom in and out, but i really need the pinch to zoom gesture back. ive tried pinch to zoom on other apps like iphoto, and preview, but it doesnt work on safari. everything else does though.. and i never messed around with the settings. When i looked into the settings, pinch to zoom was on..

can anyone help?