Human Responses to Magnetic Fields

It is well known that electric currents and fields are part of the human biological design. Sensitive magnetometers, measuring the magnetic fields from the brain, have identified response regions corresponding to stimulated areas of the body (Figure 2.29). In addition, careful dissections have shown that bones from the sinus regions of humans are magnetic, containing ferric iron deposits. Such evidence has encouraged medical scientists to search for possible physiological or psychological human reactions to the natural magnetic field and its variations.

FIGURE 2.29 ► Circles show the magnetic field pattern resulting from stimulation of the little finger. Large arrow indicates the assumed current direction consistent with the observed fields. Other brain locations corresponding to stimulated areas of the body are indicated. Figure adapted from Williamson, Kaufman, and Brenner in 1997 Naval Research Reviews.

FIGURE 2.29 ► Circles show the magnetic field pattern resulting from stimulation of the little finger. Large arrow indicates the assumed current direction consistent with the observed fields. Other brain locations corresponding to stimulated areas of the body are indicated. Figure adapted from Williamson, Kaufman, and Brenner in 1997 Naval Research Reviews.

Articles have appeared in the scientific literature indicating that relationships have been found between magnetic field disturbances and human behavior. However, scientific tests under controlled environmental conditions have yet to show conclusively that humans can detect magnetic fields. Nevertheless, variations in the global geomagnetic field level has been correlated with:

1. the number of publications by active scientists,

2. the number of admissions to mental hospitals,

3. the increase in psychiatric patient agitation at a mental asylum,

4. the number of heart attacks,

5. the number of convulsive seizures, and

6. the number of ambulance calls for stroke or heart attack.

The implication of all these correlations is that the magnetic field modifies the human mental and biological processes.

But that may be jumping to an easy but incorrect conclusion. Random associations can occur. The tests have only tried to establish a probability that the correspondence of two events is not random. Also, when two phenomena have similar cycles in activity for unrelated reasons (and the two are investigated over that same time period), the two can display a false correlation. For example, there are certainly well-known, 11-year solar-cycle changes in geomagnetic activity. Also, an equinoctial (March and September) enhancement of magnetic activity occurs because of the seasonal alignment of the Earth with respect to solar particle outflow. And there is a summer-to-winter change in the magnetic field level due to the changing solar exposure of the Earth's field in space. When a behavior that is to be compared to magnetic activity has a solar-cycle, seasonal, or annual change for some simple reason (other than geomagnetism) the computation of the correlation coefficient for the two processes, although unrelated, will show a significant value.

Here are two illustrations of misleading biomagnetism correlations. A famous and prolific space scientist, Sydney Chapman (Figure 1.10), specialized in studies of ionospheric and solar-terrestrial effects during his long lifetime. He was most interested in publishing journal articles during those years near sunspot maxima, when magnetic field recording instruments showed large solar-terrestrial storms with spectacular magnetic field displays. There was no biomagnetic field effect on this scientist, although a significant (0.5) correlation between the number of his publications and magnetic activity (Figure 2.30) was established because of Chapman's research interests.

Years

FIGURE 2.30 ► A correlation of the yearly number of S. Chapman's publications and the yearly means of sunspot numbers from 1910 through 1967.

Years

FIGURE 2.30 ► A correlation of the yearly number of S. Chapman's publications and the yearly means of sunspot numbers from 1910 through 1967.

As another example, it was found that more hospital admissions for heart attacks occurred near Hyderabad, India, when farmers were working hard at special agriculturally demanding (planting and harvest) seasons of the year. Also, the Earth, in its yearly orbit about the Sun, is better aligned to the particles and fields coming from the Sun during March and September each year; therefore, there is a corresponding increase in magnetic activity near the equinoxes. A positive correlation was reported between the geomagnetic activity index and heart-attack admissions to hospitals serving that farming community. The false relationship appeared because there was an unrelated seasonal similarity in the magnetic activity and the labor demands on the farmers.

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