Beware of inattentional blindness while testing

What's "Inattentional blindness"? and what does it have to do with testing?
I got advised about inattentional blindness by a colleague tester, who got it from another colleague tester, who got it from another colleague...

This turns "Inattentional blindness" into a Test-Myth!

Before I say anything further about it, I would like you to watch the very short video below and carefully follow it's instructions.

(Don't read below the movie yet, as it will contain spoilers)

Have you been surprised? There are different explanations for the reason behind it. (http://en.wikipedia.org/wiki/Inattentional_blindness )

• Conspicuity - The ball draws your attention.
• Mental Workload - You need to count so you focus on counting only
• Expectation - You expect only passes to see and focus on the passes only and block other content
• Capacity - You see this movie for the first time and you're not used to these exercises. You're not used to do this.

Now, what is in it for a tester? The key message is:

When you focus, DON'T FORGET TO DE-FOCUS!


This is what you do when you execute pre-scripted test cases:

• The test needs your attention - if you pass it, you better be sure about it! - Conspicuity
• You need to focus on preparing the correct data and executing the correct steps - Mental Workload
• You expect only a defect against what you are testing - Expectation
• Especially during the first run, you're not yet used to go trough the procedural steps - Capacity

It's important to achieve a goal, to pay attention and to be focused on what you're doing.
It is equally important to look around at the things you did not prepare test scripts for and find the bugs.


How can we do this?

• If you feel the urge to prepare test scripts - don't detail them into descriptive test steps. Leave yourself some space to find alternative paths. Describe your paths on the moment of execution.
• Per functionality, give yourself a time-boxed moment of time to look around in the application and find out about what you forgot about.
• Put a post-it on your screen saying "de-focus" as you will forget from the moment you try to remember.