Also, does that mean iOS and Android both fail with their grid designs for app buttons. I would be interested if someone can find an actual UX article with solid facts.
> does that mean iOS and Android both fail with their grid designs for app buttons.
Of course not. That's a highly efficient way to represent visual icons. Facebook has a much different focus: for one, it's a linear idea (in its current formulation), either by date or by how facebook decides to prioritize your stuff (grumble).
That said, I would probably much prefer to eschew all icons on android for a nice text list.