Human magnetoreception

How it works

Animals sense magnetic fields in at least two ways. One uses tiny crystals of magnetite, a form of iron oxide, that turn like compass needles. The other uses cryptochrome, a light-sensitive protein in the eye whose chemistry changes with the field¹. Humans have magnetite in the brain and cryptochrome in the retina. Neither has been shown to do anything magnetic in us.

In 2019, a team at Caltech led by Joseph Kirschvink placed volunteers in a shielded chamber and rotated an Earth-strength magnetic field around them while recording brain waves¹. When the field rotated in some directions, the alpha rhythm, a brain wave linked to a resting brain, dropped sharply. The volunteers noticed nothing¹. The team argued this is an unconscious response to the field. Critics point out that the effect appeared for only some rotations, that the sample was small, and that the result has not been independently repeated¹. The finding is controversial.

An older claim comes from the British zoologist Robin Baker. In the late 1970s and 1980s he blindfolded students, drove them out of town, and asked them to point towards home. He reported they did better than chance, and worse with magnets strapped to their heads¹. Other laboratories could not reproduce the result¹.

A 2011 study showed that the human form of cryptochrome, CRY2, can restore magnetic sensing in fruit flies that lack their own². That proves the protein can work as a sensor. It does not prove it does so in a human head.

History and culture

Speakers of Guugu Yimithirr, an Aboriginal language of Queensland, say north, south, east, and west instead of left and right, and they keep track of direction at all times³. This is a cultural skill built on ordinary cues such as the sun and landmarks. It is sometimes cited as evidence of a magnetic sense. It is not.