To back up your more skeptical points, and to hint at the linked study being a symptom of the file drawer problem, here's a study that cites the linked one and

To back up your more skeptical points, and to hint at the linked study being a symptom of the file drawer problem, here's a study that cites the linked one and which finds no statistically significant difference using a more diverse set of subjects (although still only 21 of them): https://www.researchgate.net/publication/326069864_Affordances_and_Metaphors_Revisited_Testing_Flat_vs_Skeuomorph_Design_with_Digital_Natives_and_Digital_Immigrants https://www.researchgate.net/publication/326069864_Affordanc... It does commit the fingernails-down-blackboard sin of talking about "trends" for non-significant results, but otherwise seems relatively sound. Here's another that effectively finds no significant differences, while subjects perceived flat design as more usable (although full text isn't available so I'm not sure about the methods): https://www.researchgate.net/publication/325563195_A_Comparative_Study_of_Skeuomorphic_and_Flat_Design_from_a_UX_Perspective https://www.researchgate.net/publication/325563195_A_Compara... Caveat - this is just from a quick search through studies that cited the linked article. There may be more robust studies around.