“There are no lines in nature, only areas of color, one against another.” said Edouard Manet.
Perhaps not. But by the same logic there are no colors in nature, either.
Lines and colors are phenomena that manifest themselves in our our minds. At that level, lines are very real indeed. Perceiving boundaries is a fundamental aspect of our life as visual creatures. It is hard-wired into our perception.
According to neuroscience PhD candidate Carl Schoonover:
“Lines are the bread and butter of our visual experience. They define trees, horizons, the edges of things we don’t want to bump into. Our visual system is designed to rapidly extract this meaningful information in order to make sense of the world. Consequently, the area in the visual cortex that first processes information coming in from the eyes is configured in a manner that reflects this preference for lines.”
To artists, a line is a powerful geometric entity, whether it’s a straight or curved mark on a piece of paper. According to Schoonover, the drawing by Ingres above shows that we can distinguish shapes easily with lines, which he says “taps into our visual system's predilection for line.”
So are lines merely abstract constructions—artificial conventions—that we have invented to represent our experience of nature? Do they have counterparts in the real world? Do they reflect something basic going on in our brain when we look at the world?
These can be sensitive questions for artists who do most of their work in line. They are often made to feel that what they do is just a preliminary step, or that it isn’t as advanced as what a painter does. In fact, the management of line is one of the most sophisticated skills an artist can master, and it corresponds to some of the most basic and powerful experiences of visual perception.
We use lines to describe several things:
1. A boundary of a form (B, above).
2. An edge of a surface marking (A).
3. A plane change within a form (C).
4. Or an edge of a cast shadow (D).
5. Also, a line can describe a thin form, like a tree branch or a piece of spaghetti.
A shape boundary can be regarded as a type of line. Some images are just silhouettes, such as this paper cutout by Maxfield Parrish.
At the initial level of visual processing, neuron groups in the visual cortex begin to process shape boundaries in a similar way that they process outlines drawn on white paper. But as we'll see in Monday’s post, edge detection is just one preliminary step in object recognition. The brain constructs an understanding of shape and form and space by combining information from many different cues.
Our visual system has no trouble sorting out boundaries, surface marks, plane changes, and cast shadows. At first these were difficult tasks to train computers to accomplish, but by now it’s very commonplace. Edge detection and feature extraction are exciting frontiers for people at the intersection of computer science and visual perception.
Part 2 on this post about Lines and the Brain on Monday.
Quote from Carl Schoonover in “Portraits of the Mind,” (2010)
James I was so excited this morning when I read your Lines and the Brain sub stack letter because you cite my colleague Carl Schoonover! I messaged him right away to show him in case he didn’t know and messaged my team too (I’m on the communications team at the Allen Institute). We think it’s cool that you incorporate science into your books and approach.
This morning I sat in my car in a parking lot while my wife shopped. It seemed a popular preference as I noticed many other guys were doing the same. I took the opportunity to draw my view. It all began with a blue line, and grew to of a windshield shape of the Chevy in front of me. Before she returned, many more lines captured the whole parking lot, stores, and light poles. Lines are a beautiful thing as shapes are formed and a visual experience is captured.