Do Humans Have an Inbuilt GPS?
In the world of, compasses, GPSs, satellites, etc. getting a location or tracking an object is just one button away. Do we find our way to our car in a crowded parking lot via a sort of inbuilt magnetic sense?
But do humans have an internal track-like device such as a compass? Let us find out.
Image from Unsplash
The magnetoreception, which is the study of the inherent trait to sense magnetic fields, was a study that was not taken seriously in the 20th Century by scientists.
But it was a topic that has captured people's imaginations and interests.
In the past half-century, the various scientist has shown that magnetoreception in birds, fish such as salmon, honeybees, homing pigeons, and almost every migratory animal out there.
For instance, sea turtles use the earth's magnetic field to navigate the sea. A researcher in this area, J. Roger Brothers, a biology graduate from the University of North Carolina in the USA has this to say.
Our results provide evidence that turtles imprint on the unique magnetic field of their natal beach as hatchlings, and then use this information to return as adultsSource.
The British researcher, R. Robin Baker wants to prove the human angle to this tracking by magnetic fields. So, in the 1980s he had a bus pick students who he blindfolds with different materials. Some he used a non-magnetic metal material, while in others he used a magnetic metal material in their blindfolds.
The bus drove around for a while around the countryside. He would then ask the blindfolded students to identify their takeoff point by pointing in its direction. In many trials, those without magnetic material on their blindfolds got the right direction while the ones with magnets in their blindfolds failed to do so.
This claim was counteracted by Joe Kirschvink who found Baker's experiment was contaminated.
The experiments could not stand up to the scrutiny of other scientists. But he was not to be deterred as he published a paper which could be read here in Nature Journal shortly after in 1983 where he wrote about the human sinuses being magnetic.
Intrigued, Kirschvink-now a professor at Caltech-asked for samples of the magnetite, and Baker obliged. But within hours of receiving the samples, Kirschvink determined that the samples were contaminants, artifacts from the surgical steel saw that Baker had used to slice open the bone. Gould, now thoroughly annoyed with Baker and the "waste of time" that his research has become, welcomed the news from his former Princeton colleague.
Baker eventually admitted that his magnetite samples were contaminated, but he kept pushing his ideas further, still convinced that humans had a magnetic sense. Source:Page 21
Baker had to move on to other things, but when asked to comment on his past work he said this.
I’d spent nearly a decade, tested thousands of people under all sorts of conditions, and had absolutely no doubt. Then people did a few tests here and there and claimed the experiments didn’t replicate. Even after I’d collected everybody else’s results and published that taken together, they did, in fact, constitute successful replication, nobody wanted to know.Source
The Carltech geophysicist, Kirschvink, seeing Baker's weak points tried to be more careful in testing out this assertion. Instead of using blindfolds, he opted to measure the brainwaves of test subjects using electroencephalography (EEG) and adopting an electromagnetic proof metal box known as Faraday cage.
He applied the synthesized earth's magnetic field and rotated the field anticlockwise. The neural waves known as alpha waves, which is usually in the range of 7.5-12.5 Hz, was noticed on the EEG to have dropped.
That is an indication the brain is processing an activity. Kirchvink concluded his experiment by saying that humans do have the ability of magnetoreception.
From the Baker's published work of 1983, Magnetic bones in human sinuses, magnetite played a prominent role in that work. He said that they could be found in human's sinus bone. The magnetite is a magnetic iron mineral that is highly sensitive to magnetic fields that are found in homing pigeon's beaks and many other migratory birds. The fish have it in their noses. Though also present in humans, other scientists think it is part of iron metabolism (immune system) and not a navigational feature.
The other theory is to do with cryptochrome, which is present in bird's eyes and is said to sensitive to the magnetic fields of Earth.
The birds are not the only one that has cryptochrome. Humans have two of them, the CRY1 and CRY2, that handles the body clock function. Lauren Foley from the University of Massachusetts Medical School published an article in Nature where he stated that CRY2 in human's retina could function as a magnetosensor.
Do humans have that magnetoreception? The answer is probably as there are still a lot of research ongoing. It could also be the magnetite presence may just be a part of our evolutionary past no longer needed, just like the wisdom teeth, tails,nictitating membrane, etc.
| A | B |
|---|---|
| Wikipedia : Human eye showing vestigial part of the eye (plica semilunaris) | Wikipedia : The blinking eye of a Masked Lapwing in Cairns, Queensland, Australia. The nictitating membrane closes from only one side |
But getting to find your car in that crowded park is one thing that is guaranteed to be still tough :)
References
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