Quick Eye Exam

This will blow your mind...!
Just do it - don't cheat!!!!!!!!!!!!
Try this its actually quite good.
But don't cheat!
Count the number of F's in the following text:

FINISHED FILES ARE THE
RESULT OF YEARS OF SCIENTIFIC
STUDY COMBINED WITH THE
EXPERIENCE OF YEARS

Managed it?

Scroll down only after you have counted them!

OK?

How many?

Three?

Wrong, there are six - no joke!

Read again!

FINISHED FILES ARE THE

RESULT OF YEARS OF SCIENTIFIC

STUDY COMBINED WITH THE

EXPERIENCE OF YEARS

The reasoning is further down...
The brain cannot process the word "OF".