Heuristic Analysis, Cognitive Walkthrough & User Testing are the three most important usability inspection methods so we should know when and how to use each one. Both Heuristic analysis and cognitive walkthrough are good to go as soon as the first design iteration is ready. Once their recommendations have been implemented, you can start user testing.
A little knowledge is dangerous but can be applied to Mobile App design and human interaction — particularly how Apps help us and stress us. From years of mobile product experience, I believe a design’s balance cognitive overload and resultant stress should be a major counter-balance to a Product Manager’s KPI’s to moooaaaar session time in the App. The results of a recent survey of 14,000 people revealed statistics that imply “the more competent you are with Apps, the more trapped you are”. The clear sufferers (“I feel more stressed”) are the most powerful adopters — the 26–55-year-old range and in particular 36–45. These people are mid-career, mid-family and if they are like me they have more than 5 chat Apps with business and social conversations appearing in all of them. The chat is happening while dropping the kids at soccer and their colleague on the chat wants an immediate response (they are sitting at their desk). Older age groups likely have less Apps on their phones and less competing social signals.
Cognitive friction occurs when a user is confronted with an interface or affordance that appears to be intuitive but delivers unexpected results. This mismatch between the outcome of an action and the expected result causes user frustration and will impair the user experience if not jeopardize it. User research can help uncover such problems and generate friction-free design.
Imagine a mouse-operated graphical user interface (GUI) where selecting a folder icon requires two left clicks and opening it requires a right click. This isn’t necessarily a bad way to control the GUI—however, it’s completely counter-intuitive, as our experience with GUIs for decades leads us to expect that a single left click selects an icon and a double left click opens it. The conflict between our expectation and the way the interface works is called cognitive friction. As users will not be comfortable with the prospect of unlearning a conventional way of completing an action, they will reject such a design.