I am curious to know the science behind the new kind of navigation I've been seeing lately, mostly with bigger screen phone where there is a lot of space to utilise and sometimes it's uneasy for the user to interact with the elements without using both hands, specially on the dead top or dead bottom.
Twitter, Vine are the two of many that follow this new convention. Is this ergonomically the appropriate way of interaction?
Does it make the interaction easier as now thumb's arc covers the navigation much more easily as opposed to the navigation on bottom where your thumb is cramped slightly? I'm I right or there is something more to it?
Images for reference: