A simple, modern approximation of the \"seeing\" tests in Galton's anthropometric laboratory.
What to do: Click Start, then use the Up / Down / Left / Right buttons (or the arrow keys on your keyboard) to indicate which way the letter E is pointing. The letter shrinks after each correct answer — keep going until you make an error.
Think about: At what size did you start making mistakes? Galton used tasks like this to estimate individual differences in perceptual sensitivity — one of the earliest attempts to link sensory ability to broader mental ability.