[AllenG (OP)]

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

Now count aloud the Fs in the above. Count them only once: do not go back and count them again.




















Most people only see three Fs.  There are six.
Why do we miss the others?

[Kerry]

I only counted three - took me a while to figure out where I'd missed them!  Could it be something to do with word length or their position in the word?

[Don_1]

I counted 5 first time. Its the prepositions which fail to register. I missed the 'of' in the second line.

[Karen W.]

I count 6!