Human Performance Principle #1: Even the Best Make Mistakes.

You're probably here because you saw the challenge we issued on some of our social media feeds. If you happen to be here out of an undying love for Human Performance and a deep thirst for knowledge, here it is!  

Self-Checking test: Quick! Count the number of times the letter "F" appears in the following sentence. Take your time but only count once.

"Finished files are the result of years of scientific study combined with the experience of years."

What answer did you get? Even if you think you got it right, you're probably wrong. The answer and explanation are a little wordy so we posted them on our blog at or you can click the link below. 

Check it out.

So now that we are all here, what is the answer already!? I promise, I won't drag it out like the results of a TV singing competition. 

The Answer: Most people say 3...but the answer is 6...but technically the answer is zero. Don't worry, I'll explain.

Did you answer 3? Here's why you got it wrong. Your brain typically does not recognize the letter "F" in the word "of". This could be for one of two reasons. First, the letter "F" generally sounds as you would expect; like in the words "fox" or "fast" or "finished files.”  However, in the word "of" it has a "v" sound as in "ov". This pronunciation causes the brain to fail to immediately recognize the letter because it doesn't correspond with the sound we are accustomed to hearing form the letter “f”. Second, since the word "of" is a common preposition and not a lexical word, we may just skip right over the word as we read in our heads. For years we have seen prepositions, conjunctions, and other grammatical words and have conditioned ourselves to give them little thought as we move quickly to the lexical words which reveal meaning or intent. We tend to read in shorthand in order to get straight to the point, having little time for bothersome, little words like "of".  So even though you assumed there was some sort of gimmick and you were asked to self-check, you still probably missed 3 of the letter "f"s in that sentence. Don't feel bad. The high and mighty folks that answered "6" are about to get their comeuppance. Keep reading. 

Did you answer 6? Did you? Really? (which font best conveys skepticism?) OK. Let's assume for the sake of argument that you actually read the sentence only one time and came up with 6 for an answer. There are also few explanations as to how you came to that answer; ranked in order of least to most plausible. 

1. You are a super genius who should rightly direct your scorn towards the great unwashed masses of disappointing wastes of perfectly good oxygen...everyone else.
2. You read the sentence twice and really slowed down the second time because "3" seemed like too easy of an answer.
3. You have seen this little mental gymnastics exercise before so you were keyed in to the potential trap already.
4. You actually slowed down and focused on reading each, individual word.
5. I still think you're probably lying. 

So if you answered 6 you are probably feeling superior to the people who answered 3 while simultaneously wondering what I meant earlier when I wrote "but technically the answer is zero". Keep reading.

Here are the directions again: 

"Self-Checking test: Quick! Count the number of times the letter "F" appears in the following sentence. Take your time but only count once."

 Technically, the "following sentence" referred to by the directions is "Take your time but only count once."; not the sentence that begins with "Finished files...". As you can see the "Take your time..." sentence has zero "f"s in it. If you caught that one, then try this out on your friends at your next Mensa meeting. Don't feel bad if you didn't catch the nuance because you were set up to make that mistake by vague guidance.

Look at the directions again. First, I frame it as a self-checking exercise, then I immediately put time pressure on you by saying "Quick!" and then I tell you to "Take your time". So which is it? Are you supposed to hurry or be more methodical? Just to clarify, we are a human performance company. Always take a moment to self-check. Be focused and methodical. Second, look at the structure of the directions. The structure led you to think "He's talking about the sentence which is in bold or standing alone." The structure encourages you to move past the instructions to the bold face type and thereby fail to read the instructions critically. My vague or interpretive guidance set you up for error. 

Here's the takeaway. When it's time to Self-Check, really take the time to do it right. When you're given vague or interpretive guidance, ask for clarification. When you recognize an error trap, get it fixed. Now that we are growing as an organization, here is your next set of instructions:

"Self-Checking test: 

Step 1: Count the number of times the letter "F" appears in the sentence in step 2.
Caution: Operating Experience has revealed that the letter "F" is often overlooked in the word "of". Be aware of each occurrence of the word "of" and the potential to miss the letter "f" in it.

Step 2: "Finished files are the result of years of scientific study combined with the experience of years."

Step 3: Record your answer with a newfound sense of confidence achieved by only those who have been given clear, understandable guidance.

How many of you could come up with the intended correct answer of 6? We can all apply for Mensa membership now.