I was recently reminded about the difficulty in seeing what’s there by my coffee machine. My mental model of the coffee machine is pretty simple: I put in the grounds, I add water, and I press a button to make coffee. My machine has some other features and some other buttons, but I don’t care about those since I never use them. They aren’t part of my coffee machine model.
One day while I was making coffee, I pressed the one true button. After a while, I noticed something strange: there was no coffee. I pressed the button again, with the same result. I pressed the button a third time: same result. Enemy action confirmed!
It was time to start trouble hacking. My first hypothesis was that I left out the water, but that was easily disproved. Next, I had to at least ask: Is it plugged in? Yes! I also tried unplugging it and plugging it back in, just to be thorough – but no change. I guess that only works for computers and not coffee machine.
I wasn’t making much progress, and that is usually a sign of a problem in my mental model. It was time to take a hard look at the coffee machine, trying to see what was there. I felt the coffee machine and noticed that one side was much hotter than usual. I then looked hard at the mystery buttons, and for the first time, I noticed that one of the mystery buttons controlled whether the coffee machine used the carafe or whether it used a separate single-serve dispenser. And in fact, this button was set to the single-serve setting!
Now the pieces of the puzzle were coming together. The coffee machine was in single-serve mode, but I had not added water to the single-serve reservoir. I had only added water to the reservoir for the carafe. When I pressed the one true button, the coffee machine tried to heat up the single serve reservoir, but there was no water there. The heating element got too hot, and the coffee machine shut down as a safety measure. This explained why the coffee machine was unusually hot – repeatedly pressing the one true button with no water in the single-serve reservoir generated quite a bit of heat.
I could finally bring the trouble hacking session to a satisfying conclusion. I switched the machine back to carafe mode, pressed the one true button, and successfully brewed a pot of coffee. Not only did I have a fresh pot of coffee, but I had an updated mental model of the coffee machine and I could explain all of the anomalous observations (like the unexpected heat).
The point of this story is that it is remarkably difficult to see what’s there even in simple systems. Once you decide to ignore something because it seems unimportant, it can take an act of will to take a fresh look at a system and permanently change the way you perceive it. Even today, I rarely look at anything other than the one true button – but if I don’t get my coffee, the single-serve setting is the first place I look!