The challenge
Hold your thumb up at arm's length and focus on a small detail on your thumbnail. Now, without moving your eyes from that detail, try to read text in the surrounding area of the room. What do you notice about your peripheral vision?
Objective
Experience the difference between high-resolution foveal vision and low-resolution peripheral vision.
Materials
Your thumb and any text in your environment.
Description
The fovea covers only about 2° of your visual field, but because your eyes move constantly, the brain creates the illusion of a uniformly sharp image. This is called saccadic masking. The experience is analogous to selective attention in everyday life: we have high clarity only in the narrow zone of our focus, and we often overestimate how much we are actually perceiving about the broader situation.