From the article:
Ira isn’t an actual human being—he’s just a computer model—but you’d be forgiven for not being able to tell the difference.
Well...I wouldn't forgive me. You can tell by:
- The crazy amount of unnatural (colored) lighting used to hide low detail and/or too-uniform shading. Show me the same head model in a field on a cloudy day at 2pm in March
- The limited polygon count; look at the edges of his ear (which is a bit weird looking in itself btw)
Instead of unnatural lighting they have a lot of added skin detail (wrinkles, dirt) to hide too-uniform shading. There's a lot of detail / noise / subtle imperfections in real life you don't normally think about, but when it's not there you instantly notice it on a subconscious level.