Human brain can detect changes in Earth's magnetic field: Study

Many people are able to unconsciously detect changes in the Earth's magnetic fields, according to scientists who claim to have found concrete evidence of a new human sense -- magnetoreception.

Researchers from California Institute of Technology in the US and the University of Tokyo in Japan offer experimental evidence that human brain waves respond to controlled changes in Earth-strength magnetic fields.

"Many animals have magnetoreception, so why not us?" said Connie Wang, lead author of the eNeuro study published in the journal eNeuro.

For example, honeybees, salmon, turtles, birds, whales, and bats use the geomagnetic field to help them navigate, and dogs can be trained to locate buried magnets.

It has long been theorised that humans may share a similar ability.

However, despite a flurry of research attempting to test for it in the '80s, it has never been conclusively demonstrated.

"Aristotle described the five basic senses as including vision, hearing, taste, smell, and touch," said Joseph Kirschvink, from Caltech.

"However, he did not consider gravity, temperature, pain, balance, and several other internal stimuli that we now know are part of the human nervous system," said Kirschvink.

"Our animal ancestry argues that geomagnetic field sensors should also be there representing not the sixth sense but perhaps the 10th or 11th human sense to be discovered," he said.

To try to determine whether humans do sense magnetic fields, researchers built an isolated radiofrequency-shielded chamber and had participants sit in silence and utter darkness for an hour.

During that time, they shifted the magnetic field silently around the chamber and measured participants' brain waves via electrodes positioned at 64 locations on their heads.