Nielsen Norman Group have also ran a study, with results similarly unfavorable for flat design: https://www.nngroup.com/articles/flat-ui-less-attention-cause-un

Nielsen Norman Group have also ran a study, with results similarly unfavorable for flat design: https://www.nngroup.com/articles/flat-ui-less-attention-cause-uncertainty/ https://www.nngroup.com/articles/flat-ui-less-attention-caus... (Possibly it's not the only study of theirs on the topic.) Notably, NNG uses a more 'real world' methodology, testing realistic user tasks in browsing websites. For the unfamiliar, 'Nielsen' is Jakob Nielsen, an authority on usability, working and writing on it for two decades now, and he's a big advocate of usability testing in design process. (BTW, “Designing Web Usability: The Practice of Simplicity” of his is an excellent writeup on how websites should function—I'd bet it's as valuable today as it was in mid-2000s for me, because the functioning of humans doesn't change.) They also noted that flat design has made some steps back to the immediate recognition of the olde pseudo-3d interfaces, notably with 'Material design': https://www.nngroup.com/articles/flat-design/ https://www.nngroup.com/articles/flat-design/ But not many steps.