Some people on this planet will spend at least part of today with their own mother. For others, this will be impossible for any number of reasons and they may think about her by pulling up a picture in the mind's eye or actually looking at a photograph. Recent studies have shown how the human "eye" can outperform a "camera" in some aspects (although the mechanism of research is so complex it is a challenge for my brain to understand the process). Basically, as the author puts it, visual images are projected by the lens of the eye onto a sheet of photoreceptor cells (known as rods and cones) in the retina. Much like pixels in a digital camera, each photoreceptor generates an electrical response proportional to the local light intensity.