In the late 1970s there was growing public paranoia regarding high voltage power lines. The story went that the power lines’ magnetic fields were causing leukemia in children.
A study published in March of 1979 in The American Journal of Epidemiology found a loose correlation, which sparked massive public outcry. This study resulted to further, more extensive studies, the vast majority of which found no correlation.
There was also reasonable criticism within the scientific community directed at the 1979 study for failing to control for other various contributing factors. Yet still, the American public became incredibly paranoid regarding magnetic fields for quite some time. Even to this day, every once in a while a new study will be published that shows loose correlation and suddenly it’s all the news media wants to talk about.
This stems from a fundamental misunderstanding of the meaning of scientific terms on the part of the general public. As is taught in any introductory science class, correlation does not equal causation.
And now a new threat seems to be on the rise: cellphones. A 2009 report by the World Health Organization classified electromagnetic field radiation from cellphones as “possibly carcinogenic” and recommended cellphone users take precautions.
What many missed is that the same report went on to say that there was only “limited evidence of carcinogenicity” and that “chance, bias, or confounding could not be ruled out with reasonable confidence.”
This is because, among the various studies done on this topic over the decades, only a small handful have shown any correlation between any form of damage and cellphone use.
This shouldn’t be surprising to anyone who is aware of the nature of radiation and the difference between ionizing and non-ionizing radiation.
Simply put, what the public often considers to be radiation is actually only ionizing radiation, a specific form of radiation that causes particles to become ionized, which can in turn cause damage to cells and DNA, which in turn causes cancer.
Radiation is simply the process of energy traveling through space. Examples of radiation include light, heat, or radio waves.
Of course, the topic of radiation is much more complex than all that, as ionizing radiation is present constantly in our day to day lives. Eating a banana, flying on an airplane, or even just sleeping next to someone exposes us to ionizing radiation, just not in numbers great enough to have any sort of meaningful impact.
However, the basic principle that non-ionized radiation does not cause cancer still stands, as there is no scientific reason for it to do so. The only potential way that it can cause problems is from the heat it generates.
So, while holding a cellphone to one’s head does cause a slight temperature increase, this increase is significantly less than simply exposing one’s head to direct sunlight.
There are various issues with the claim that cellphones can cause brain tumors, such as the vast majority of studies on the subject finding no correlation whatsoever and those that do finding only loose correlation that cannot be backed up with evidence of causation. In fact, some studies even found lessened correlation.
Why then is there all of this public outcry? It’s a combination of the byproduct of a 24 hour news cycle and the general public’s lack of understanding of how science works. Whenever a study is released that isn’t shocking or doesn’t challenge established norms, the news loathes reporting on it. After all, it’s just the same old boring story.
But if a study is released that makes a dramatic claim then that will get people watching. Despite the overwhelming numbers of studies done that show no correlation, all people will hear about are the studies that do seem to find correlation.
Even then, if people understood what correlation actually means, they wouldn’t be so afraid. This is similar to how in scientific jargon theory means something drastically different from what it means to the general public. For instance, gravity is a theory yet people still drag out the tired argument against evolution of it being just a theory.
Correlation means only that there is some link between two conditions; it says nothing about the cause of the link.
One example often used to illustrate this point is the fact that in the summer months, the occurrences of sexual assaults increase. Also, during the summer months, more ice cream is sold than during any other season. Therefore, there is a correlation between increased ice cream sales and increased cases of sexual assault.
This does not mean that people are more likely to commit sexual assault when they buy more ice cream. Why, that’s as ridiculous as nonionic radiation emitted from cellphones causing cancer.