We're not using it efficiently, though. And the whole field of UI / UX actually now moves in completely opposite direction - towards how to make things least efficient and least information-dense, but more and more pretty so that it sells and addicts better.

I'd love to see some research into just how much data can humans really process if humans are properly trained and the data is cleverly presented.

> we only use it for serial input.

Consciously. Unconsciously, your mind is always looking for threats - big movements - in the periphery of your view. It's a co-processor which runs through a lot of data in order to direct your conscious mind.

> Perhaps it would require too much energy

I think that the problem of energy could be overcome. I think that instead of getting too hot, it would simply produce too much waste, and since the waste evacuation system for your brain only really operates when you sleep (at least, last I heard), this would be the main limiting factor.