Scenery After Sunset

We began a longer than usual walk while it was still light. It was sundown about the time we were at the halfway point and nearly dusk by the time we got back to our car. It was cloudy, and the half moon only cast a faint, dull glow on the grass and the path. With the exception of some birch, the trees were black.

It’s an interesting transition, going from daylight to sunset to dusk. As the light fades, so does our ability to discern color. The color receptors of our eyes need much more light in order to function properly than the “black and white” light receptors. What’s more, our ability to see fine details is quite limited in low light: the part of our eye that focuses on small features—the part that we use when we look carefully at something—is made almost completely of color receptors. When it’s quite dark, we really only see dark shades of gray and shadows, and not very crisply at that.

Near the end of our walk, three deer crossed the path and stood in the field to our right. I only saw them because I wasn’t looking directly at them. Our peripheral vision is quite sensitive to movement and happens to be where the “black and white” receptors are, which is valuable for detecting predators and automobile traffic, if they are different.

As the deer stood in the field, watching us watch them, the irony struck me again. Because our nature is of course to focus on something that grabs our attention, we end up being able to see it less clearly than if we looked just off to the side of it, where our vision is more sensitive under low light conditions. (I suppose that’s part of why we’re not nocturnal animals. If we were supposed to be very active at night, we’d have eyes more like cats or owls or deer, which gather more light and use it more efficiently.)

It’s a strange but illuminating kind of effort to look not-quite-at something in order to see it more clearly.