The following test is featured in stranger and stranger by Robert McMullen.
Read this sentence:
FINISHED FILES ARE THE RE-
SULT OF YEARS OF SCIENTIF-
IC STUDY COMBINED WITH
THE EXPERIENCE OF YEARS.
Now count the Fs in that sentence.
Count them ONLY ONCE. Do not go back and count them again.
Scroll down for the answer...
There are six Fs in the sentence. Apparently, a person of average intelligence finds three of them. If you spotted four, you’re above average. If you got five, you can turn your nose up at almost anybody. If you caught six, you are a genius. There is no catch. Many people forget the OFs. The human brain tends to see them as Vs and not Fs.