Students Search for Sixth Sense

UC Berkeley students have been spinning around in chairs in search of a "sixth sense" that may allow human beings to innately distinguish north from south, and east from west without the aid of a compass.

Daily Cal Staff Photos/Johnny Hawkins Freshman Jennifer Kho blind-folds and spins her subject, Audrie Lee, who is then asked to point in the direction she was originally facing. Magnets on different colored headbands serve as experimental control and variables.

It has long been known that human beings can utilize magnetism and the Earth's magnetic field to navigate direction through the means of a compass. A team of UC Berkeley students, however, are looking into the possibility that the human body, like a compass, may also possess the ability to read and manipulate the Earth's magnetic field.

For approximately 40 years, scientists have found that a variety of animals use the Earth's magnetic field to navigate, according to UC Berkeley Integrative Biology Professor Roy Caldwell. According to Caldwell, who teaches a freshmen seminar that is conducting the magnetic experiments, animals such as homing pigeons, salamanders, honeybees and even snails exhibit an innate ability to "read the Earth's magnetic field."

Research has shown that animals use two possible mechanisms to read magnetic fields. The most common of these possible navigation mechanisms involves the use of magnetite - a small iron-magnetic material or crystals located in animal cells.

Crystals are concentrated at different parts of the animal bodies, such as the brain of a turtle or the nose of a salmon. As magnetic fields around the animal change, the magnetite orients itself differently in the cell and causes the animal to register a change in direction.

The other possible mechanism involves a type of visual receptor. When the eye captures a photon of light, certain molecules in the eye react and change. How easy it is to cause that change depends on the orientation of the magnetic field in and around the eye and photon of light, Caldwell said.

This semester, students in Caldwell's freshmen seminar class have been busy studying navigation in humans in addition to animals. Among these students is Jennifer Kho, a first-year intended Molecular Cell Biology major, who has been working to determine whether magnetic fields play a role in human navigation.

Robert Baker, an English scientist, conducted an experiment 20 years ago to determine whether magnetic fields affect human navigation. Baker published a paper stating that the results of his experiment proved that human beings do use the Earth's magnetic field to navigate. The class experiments drew heavily on Baker's findings, said freshman Eric Chak, a member in the course.

Students worked together to design an experiment to answer this question and have been testing subjects for approximately three weeks.

"We are not trying to explore the effect of magnetic fields on our brains," Kho said. "We are just proposing that they may hinder our navigational skills."

The experiment requires that each student test six subjects, three males and three females. Each student tested each subject individually and gathered their subjects from amongst other UC Berkeley students.

The students tested each subject in a "testing room," said freshman Kevin Jeung, who also took part in the course and experiment.

During the experiment, subjects sat on a spinning chair and wore both blindfolds and earplugs. The students then placed a metal disk attached to a headband onto the subjects. There were two types of disks, one magnetic on - designed to disrupt the Earth's magnetic field - and one not. Neither the students nor the subjects knew which disk was magnetic, Chak said.

After having some time to sit and "get a feel" for the original position, the students spun their subjects in order to cause disorientation. After a few turns, the students stopped the subjects and asked them to point in the direction of their original position. The students also asked the subjects how confident they felt that they were correct and upon what basis they made their decision.

The results of the experiment have, thus far, not made it conclusive whether humans have the ability to navigate using magnetic fields.

"Based on our results, it seems that magnets have a random effect on humans, or maybe even none at all in their ability to determine direction," Jeung said.

Although the results were not conclusive, they did have significance, said Caldwell, who pointed out that there was a slight, yet evident trend in the subjects who were correct in determining their original positions.

"After compiling all the data, our results are inclusive," said Kho. "Some isolated trials show that the magnets do affect sense of direction. However, as a whole, such a bold conclusion cannot be drawn."

Though the experiment did not produce a definite answer to the questions the class first set out to answer, both Kho and Jeung said they were able to take something away from having done the experiment.

The students said they managed to learn how to design an experiment and what variables to watch out for, said Jeung.

Students were required to figure out every component of the trials, ranging from the number of subjects to the place to hold their experiment.

Outside factors such as noise from elevators or air ducts that might have influenced subjects also had to be considered to devise a way to prevent the biasing of their subjects from these factors and in order to preserve the quality of their data.

"There are a lot of (things) that you have to look for during the actual conductance of the experiment," said Jeung. "You have to be aware of what's going on so that the experiment runs smoothly and you get accurate data."

According to Caldwell, the fact that his students were able to gain experience about conducting experiments exceeded any need to find a conclusive answer to the question of a possible human "sixth sense."

"The purpose of this set of experiments is not just to find out something about human navigation," he said. "This study is really about how hard it is to properly control an experiment. The seminar is really about how to design experiments and do good science."

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