Psychology
Understanding the Role of Vision in Human Perception
Quick fact
Although the eye can detect a single photon, the brain does not act like a camera: it constructs a coherent visual scene by actively interpreting ambiguous sensory signals, which is why optical illusions can trick us so reliably.
Why this is interesting
You trust your eyes to show you the world as it is—but they don't. Why can a static image appear to move, and why do colours seem constant under changing light?