We marveled at the stars of Illustra’s film Metamorphosis — Monarch butterflies — migrating 3,000 miles from Canada to Mexico with cues from the earth’s magnetic field. Then there were the Arctic terns in Flight: The Genius of Birds with similar magnetic abilities. Who could forget the sea turtles in Living Waters migrating thousands of miles by that same invisible force through the oceans without benefit of any other navigational clue?
At the end of the third film in the Design of Life series, Illustra listed two dozen types of animals, including insects, reptiles, birds and mammals, that have the ability to use the magnetic field for orientation or navigation. A question naturally arises, are humans clueless, magnetically speaking? New research suggests an answer: maybe not.
Last month, we noted a study that shows how deer orient themselves on a north-south axis, and wondered if humans have a latent magnetic sense. Now there is new evidence that we might. The champion of human magnetic perception is Joe Kirschvink of Caltech. In Science Magazine, Eric Hand talked about the lively debate over this possible sixth sense:
Birds do it. Bees do it. But the human subject, standing here in a hoodie — can he do it? Joe Kirschvink is determined to find out. For decades, he has shown how critters across the animal kingdom navigate using magnetoreception, or a sense of Earth’s magnetic field. Now, the geophysicist at the California Institute of Technology (Caltech) in Pasadena is testing humans to see if they too have this subconscious sixth sense. Kirschvink is pretty sure they do. But he has to prove it. [Emphasis added.]
A photo of Kirschvink under an EEG sensor cap in an electrically charged cage gives the article a sci-fi appeal. His hand-waving doesn’t help the picture:
He takes out his iPhone and waves it over Keisuke Matsuda, a neuroengineering graduate student from the University of Tokyo. On this day in October, he is Kirschvink’s guinea pig. A magnetometer app on the phone would detect magnetic dust on Matsuda–or any hidden magnets that might foil the experiment. “I want to make sure we don’t have a cheater,” Kirschvink jokes.
But Kirschvink is no charlatan wearing a pyramid hat. He’s a respectable scientist at Caltech, an expert in measuring remanent magnetization in rock. He uses high-tech equipment in his quest to prove human magnetosensation, taking great care to eliminate factors that might fool his instruments. In fact, he participated in falsifying claims about human magnetoception coming from Robin Baker in the UK. In the 1980s, Baker had claimed experimental evidence that blindfolded Sherpas in Nepal could point in the direction of home after a twisty bus ride, or point north after being spun in a chair. Kirschvink showed those experiments were not reproducible.
Now, however, he’s on a quest is to find evidence for a human magnetic sense. Finding this “needle in a haystack” is particularly difficult, Eric Hand notes in a companion article in Science, because magnetic field lines penetrate the entire body. There’s no obvious magnetic organ; “The receptors could be in your left toe,” Kirschvink says. Moreover, there’s been a longstanding debate between the magnetite hypothesis and the cryptochrome hypothesis, Hand expounds in the second article. But the external evidence is compelling:
For much of the 20th century, magnetoreception research seemed as unsavory as the study of dowsing or telepathy. Yet it is now an accepted fact that many animals sense the always-on, barely there magnetic field of Earth. Birds, fish, and other migratory animals dominate the list; it makes sense for them to have a built-in compass for their globe trotting journeys. In recent years, researchers have found that less speedy creatures — lobsters, worms, snails, frogs, newts — possess the sense. Mammals, too, seem to respond to Earth’s field: In experiments, wood mice and mole rats use magnetic field lines in siting their nests; cattle and deer orient their bodies along them when grazing; and dogs point themselves north or south when they urinate or defecate.
We don’t suppose that architects will take pains to orient toilets on a north-south axis in their building designs any time soon, but Kirschvink has found some empirical evidence that magnetosensation exists in humans. If mammals have it, we should, too. In fact, “The same candidate magnetoreceptors are found in humans,” Hand says. Are they functional? Or are they disappearing traits, like the wings on flightless birds?
Kirschvink had already detected magnetite in bacteria and mollusks decades ago. Now, he uses Faraday cages, wire coils and EEGs to test for a human magnetic sense. In addition to his students, he has tested himself — thus, the photo of him with an EEG cap. He applies appropriate controls and randomization in trials to avoid the flaws in Baker’s claims. Last April in the UK he delivered his latest evidence.
Then, in the last talk of the first day, Kirschvink took the podium to deliver his potentially groundbreaking news. It was a small sample — just two dozen human subjects — but his basement apparatus had yielded a consistent, repeatable effect. When the magnetic field was rotated counterclockwise — the equivalent of the subject looking to the right — there was sharp drop in α waves. The suppression of α waves, in the EEG world, is associated with brain processing: A set of neurons were firing in response to the magnetic field, the only changing variable. The neural response was delayed by a few hundred milliseconds, and Kirschvink says the lag suggests an active brain response. A magnetic field can induce electric currents in the brain that could mimic an EEG signal — but they would show up immediately.
Kirschvink also found a signal when the applied field yawed into the floor, as if the subject had looked up. He does not understand why the α wave signal occurred with updown and counterclockwise changes, but not the opposite, although he takes it as a sign of the polarity of the human magnetic compass. “My talk went *really* well,” he wrote jubilantly in an email afterwards. “Nailed it. Humans have functioning magnetoreceptors.”
PhysOrg reported on this meeting, too, describing the experiments in more detail. A team in Japan is also showing reproducible effects. This month, also, scientists at the University of Tübingen have identified an “inner compass” in the brain in the form of “head direction” cells. These are “considered very important in keeping track of one’s position in one’s surroundings, much like a GPS system.” If rodents have these cells, it’s conceivable all mammals do — including us.
Kirschvink’s confidence is not echoed by all. Amazing, if true; they think. But he is already leaping ahead into the meaning of this sense. Eric Hand writes:
But he relishes the thought of showing, once and for all, that there is something that connects the iPhone in his pocket — the electromagnetic laws that drive devices and define modernity — to something deep inside him, and the tree of life. “It’s part of our evolutionary history. Magnetoreception may be the primal sense.“
Stephen Meyer might chuckle at some of Kirschvink’s flights of fancy, such as his 1992 hypothesis that the Cambrian explosion was caused by retreating glaciers from Snowball Earth, or by Earth’s axis tipping 90 degrees. “The climatic havoc from this geologically sudden event also would have spurred the biological innovations seen in the Cambrian,” Hand says of this notion. Kirschvink also thought that magnetite crystals in the Martian meteorite that made headlines in the 1990s and 2000s showed evidence of life. Neurobiologist Kenneth Lohmann, an expert on magnetic navigation in sea turtles, put a nice spin on this. “He’s not afraid to go out on a limb,” Lohmann said. “He’s been right about some things and not right about other things.”
The evolutionary theory would require magnetic sensation arising by chance in the earliest bacteria, then persisting throughout the entire tree of life but disappearing or lying dormant in many species. Either that, or evolutionists would have to postulate that it arose independently in distant parts of the tree unrelated by nearby ancestry. But magnetic fields are invisible; why would any organism even be aware of them? And if perchance a bacterium or other creature suddenly engulfed some magnetite and then somehow sensed the field, how would it know the information is useful? How did the information become encoded in the genome to both sense magnetism and respond to it?
Design advocates do not find it surprising that diverse animals can share methods of sensing invisible forces available to them. Intelligent designers know how to make sensors. They know how to make responders. Whether it’s for light, sound, touch, odor, or taste, sensors in the living world are marvelously complex. One expects the magnetic sense that scientists are just now coming to understand will be no less so.