I'll See It When I Believe It
I received the following e-mail from my mother-in-law the other day. I suspect this is an old bit of spam that is recirculating.
"I cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the human mind. Aoccdrnig to a rscheearch taem at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod aapepr, the olny iprmoatnt tihng is taht the frist and lsat ltteers be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Such a cdonition is arppoiately cllaed typoglycemia."
This probably isn't really a Cambridge University study, I'm pretty sure there's no such condition called typoglycemia and the explanation left out "context." That aside, there's an important lesson in the above for anyone in the quality field.
This particular e-mail caught my eye because it beautifully illustrates the problem with inspection. As an editor, it's easy to read over a word that is absolutely, completely misspelled and not catch it. The mind sees what it wants to see. That's why multiple editors read the same pages over and over again to help mitigate this problem. Even spell check doesn't always work. How many times have we caught "quality manger" or "pubic courses"? More than once or twice, believe me.
And it isn't just editors. Inspectors of all types suffer from similar problems. Having been an electronics inspector I can speak for myself. For instance, when reading the color code on resistors, you may be looking for a 1 k ohm resistor with a 10-percent tolerance at a certain location on the circuit board--four stripes: brown, black, red, gold--which you see about a million times. Then you see brown, black, orange, gold. Even if you're wide awake it's easy to "see" red even though the stripe is clearly orange. The first two bands are correct and the last band is correct, so your mind fills in the rest.
The same problem occurs when reading any kind of instrument with a digital numeric readout. If the right numbers appear, but some of them are transposed, your mind simply rearranges them the way it wants them to appear.
Similar filtering takes place at not only the pattern-recognition level but during raw sensory input. For instance, grab a white sheet of paper off your desk and look at it. It "looks" white, right? Unless you happen to be outside, white is most likely not what your human optics see. If you are under fluorescent lighting what you actually see is a green-tinged piece of paper. If under incandescent, you see an orange-tinged paper. Your mind does a kind of auto-white balance without you knowing it. The same phenomenon happens with the olfactories. Do any of you work in smelly environments? "What smell?" you say.
That's the beauty and the pain of the human mind. The very attribute that allows us to extract information from seeming randomness or to filter out the signal from the noise is what makes it the enemy of inspectors. Part of the reason you can't inspect quality into a product is because you're constantly fighting your own brain's attempt to make things be the way it thinks they should be.
Hmmm, maybe if we designed processes to make things be the way they should be from the start…