Question

A real-life visual illusion is the "moon illusion." When the moon is close to the horizon, the full moon seems larger than it does when high in the sky. Rationally we know that the moon does not change size according to its position in the sky. Based on what you have learned about optical illusions, why do you think the moon illusion occurs?

Answer 1

This happens because whenever the moon is close to the horizon, objects on Earth that are similar to the moon on your retina contribute to a misperception or an incorrect misconception of distance and size.

The brain observes the low moon as smaller and therefore bigger than the higher moon in the sky.