This was developed by an R & D department at Harvard Uni. Take your time and see if you can read each line without a mistake. The average person over forty can't do it. 1.This is this cat. 2.This is is cat. 3.This is how cat. 4.This is to cat. 5.This is keep cat. 6.This is an cat. 7.This is old cat. 8.This is fart cat. 9.This is busy cat 10.This is for cat 11.This is forty cat. 12 This is seconds cat. Now go back and read aloud the third word in each line from the top down.