You don't need a peer-reviewed study to know that when people surf the web on their smartphones, they're not going as deep.
We swipe instead of click.
We scan instead of read. Even our personal email…
We get exposure to far more at the surface, but rarely dig in.
As a result, the fine print gets ignored. We go for headlines, not nuance. It's a deluge of gossip and thin promises, not the relatively more immersive experience of the desktop web.
And of course, the web was a surface treatment of a day spent with books and in uninterrupted flow on a single topic.
It's not an accident that blog posts and tweets are getting shorter. We rarely stick around for the long version.
Photokeratitis (snow blindness) happens when there's too much ultraviolet–when the fuel for our eyes comes in too strong and we can't absorb it all. Something similar is happening to each of us, to our entire culture, as a result of the tsunami of noise vying for our attention.
It's possible you can find an edge by going even faster and focusing even more on breadth at the surface. But it's far more satisfying and highly leveraged to go the other way instead. Even if it's just for a few hours a day.
If you care about something, consider taking a moment to slow down and understand it. And if you don't care, no need to even bother with the surface.