All too often UI styles are based on a designers' own opinion. That's not necessarily important. It's important that users trust the application for what it promises to deliver. Using an appropriate UI style I hope to emphasis this.
For example if the product is an online file manager that emphasises security, the UI should 'feel' safe in its style. Having a windows95 style might not convey security and would therefore be a bad choice.
If your app promises to make people happy, you should make sure you have a 'happy' visual style. How would you test that?
What methods can I use to test whether UI styles match product values?
(I'm trying to keep the question global so others can benefit from it.)
What I'm thinking of doing is create 5 mockups of exactly the same page in a different style. Do a 5 second test for each style where we ask the participants to rate the design (1 to 5 stars) on the product values, topics like security, seriousness (it's corporate) etc.