When we use software (or just about any product), we subconsciously paint a mental model in our heads for how we believe the product should work. A mismatch between your user’s mental model and how you’ve designed your software product or website could be catastrophic.
Many software product companies do not place enough weight on the importance of understanding their user’s mental models because a mental model is based on a user’s belief — not facts. In other words, it may be a fact that your product is designed to do XYZ but if your user’s think it works like ABC, you’re in trouble. During usability tests, companies are often surprised by what they see and get frustrated to see their product attempt to be used in a way it was never designed to be used.
I recently helped a family member get set up with a new MacBook (no, that is not her in the photo). To make everything work as she expected and to answer any questions she may have, I had her visit a few websites she normally visits and logs into. After successfully logging into her banking site and making sure she was able to access everything she needed, my usability testing habits kicked in and I asked her what she would normally do next when she wanted to go to another website. She told me she would first log out of the site and then click one of the bookmarks. For some reason, I asked her why she felt she needed to log out of the site first before going another site. Now, logging out of a site that contains lots of PII is not a bad idea – but since her computer never leaves her house, and she’s the only one that ever uses it, and the site would eventually time out and log her out anyway, I asked. She answer “Well, I don’t want other people to get in”. I asked her “What other people? People coming into the house?”. She replied “Oh no, I’m not worried about that. I mean other people on the Internet.” It turns out, her understanding (mental model) of how website security works is similar to accessing your safe deposit box at a bank. You have to unlock the little door inside the bank vault to access your safe deposit box (Logging In). When you’re done, you put the box away and lock the little door (Logging out). But, if you don’t lock the little door, anyone else can access it and take all your stuff.
Yes, this may be an extreme scenario of a mismatched mental model but it acted as a good reminder for me to make sure we always learn as much as we can about how the user’s think before we design – so I thought it was worth sharing.