It's crazy to say that horses have a visual advantage over humans, but with eyes on opposite sides of their heads, they surely don't see in three-dimensional terms like we do. There are times especially for beginners when seeing less--seeing a scene as an utterly flat, two-dimensional plane--would benefit beginning artists as they try to render. Given our brain power, however, we would still get in our own way--often the problem is not what we see, but what we know or assume about a subject. Noses look thusly. That stream curves gently along that bank, not in straight horizontal lines. That forearm is 13 inches long, even though I only see a foreshortened portion of it. Still, if you doubt that three-dimensionality isn't a complicating factor when depicting a scene, consider the difficulty of painting a landscape en plein air versus painting a photo of the scene. It's not just about the rogue wind that keeps threatening to tip over your easel that makes plein air painting
more challenging--having the camera do the work of flattening the view is quite a help strictly in terms of simplification.
The flip side of this is that just seeing the flat scene, seeing the constricted value range of the camera, not being able to move your head to get a glimpse of why an edge on the subject looks the way it does is decidedly limiting. Too much information is rarely a bad thing. The artist's job is to build a proper internal filter for his or her eyes--to simplify and understand in the brain, based on full disclosure by the eyes.
More than one artist I've spoken with has cited the importance of walking around your subject a few times, studying all angles, gathering knowledge of all sides of the model, building, rock, etc. "It's always a good idea to know your subject," artist Claire Van Vliet once told me in an interview. "So move around it. You don't want to be a copyist. You want to know where the rock is going when it leaves your view--keep in mind that all of the edges are totally arbitrary based on your vantage point."
See fully, then simplify the vision. Sorry, Mr. Ed--looks like the advantage stays with us peoples.