Our brains are hard-wired to find meaningful images in random lines and shapes—even if those figures are on the moon.

For as long as humans have lived on Earth, the moon has been our nearest celestial companion and a rich natural canvas for the human imagination.

In Western cultures, perhaps the most familiar vision is "the man in the moon." In East Asian cultures, moon-gazers might point to a rabbit; in India, a pair of hands. From ancient times to the modern era, from different spots on the globe, a tree, a woman, and a toad have all been found hiding in the moon's shining face.

• Joel Voss, a cognitive neuroscientist at Northwestern University, Chicago, is studying how our brains help us ascribe meaning to otherwise random assortments of shapes and lines.
• In studies, he has presented research participants with computer-generated squiggly lines—meaningless sh...