This mini human factors test is going around Facebook.
Once you find the mistake it becomes almost impossible not to see it.
This illustrates two concepts
1) we see what we expect to see and our brain “corrects” what does not conform and therefore we can easily misread labels
2) Only hindsght is 20/20. When investigating an error after the fact, hindsight bias may cause one to think the error was foolish and was easy to detect at the time. Now that you see the error in this little picture it seems to be so evident that you wonder how it could have been missed initially
This is why we need barcode medication identification systems for preparation and administration.
And this is why it is so important to understand what was actually known at the time of an error and not what we know in hindsight. Many errors occur when people are doing what they always have done. Usually there is no significiant deviation from norm.
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