The Psychology of Cancer Clusters

By George Johnson | March 28, 2013 8:46 pm

“About Cancer and Cancer Clusters.” Delaware Department of Health and Social Services, Division of Public Health

My last two posts about the Erin Brockovich case are part of a tangent that began with an article I wrote for Slate about cancer clusters. Before continuing I want to step back and tie this all more firmly into one of the themes of this column: how the human brain, flooded with the information storming our senses, is driven to pick out patterns — or to impose them if they are not  there. This is how I put it in my book, Fire in the Mind: Science, Faith, and the Search for Order:

Psychologists have found that if you put people in a room with a contraption of lightbulbs wired to blink on and off at random, they will quickly discern what they believe are patterns, theories for predicting which bulb will be next to blink. Once a person becomes enmeshed in an ideology or a scientist in a hypothesis, it is difficult not to see confirmation everywhere. Our brains are wired to see order, but we are cursed with never knowing whether we are seeing truths out there in the universe or inventing elaborate architectures.

That is what makes cancer clusters such a vexing phenomenon. In my piece for Slate I concentrated on the case of Toms River, New Jersey. There was no question that the water had been irresponsibly polluted. And there appeared to be more childhood cancer than in the general population — 56 cases in the entire township over 13 years when 43 would have been normal. In the end a very thorough investigation and statistical analysis failed to find an association between pollution and any of the cancers except one: leukemia.* Even then the epidemiologists could only say, with great uncertainty, that a few of the cases might have been caused by the pollution, but only among the girls and not the boys. This is what I wrote:

As epidemiologists parsed the numbers this way and that — including one age group in their calculations and excluding another, or making different assumptions about when contamination reached the water taps — were they closing in on a deeply hidden truth or picking and choosing among the data? There was no biological explanation for why male and female fetuses would respond differently to the carcinogens. If limiting the analysis to girls hadn’t uncovered an association, would the next step have been to distinguish between those with brown hair and blond?

Were the leukemias caused by the pollution or were they a random fluctuation in the numbers? We will probably never know.

For the Brockovich case, which involved the town of Hinkley, California, the evidence was even weaker. The water was indeed polluted, and people were getting cancer, though (as later discovered) in no greater numbers than for the general population. It just seemed that way. As in Toms River the companies responsible for the contamination agreed out of court to pay a large settlement. I think there was justice in that. Their actions had been irresponsible and caused fear and unending agony among people who will always wonder why their children got sick.

For those of us far away from Hinkley or Toms River, our brains also demand a satisfying explanation. But we will settle for a good story. A town was polluted. Its citizens got cancer. A villain must be found and made to answer. But you can sympathize with the children and abhor the polluters without believing there was really a connection.

*Updated: Dan Fagin, the author of Tom’s River, has persuaded me to soften the wording of this sentence: “In the end a very thorough investigation and statistical analysis ruled out pollution as a cause of any of the cancers except one: leukemia.” “Failed to find an association” is more precise. Here is the study I’m referring to (a pdf) and a page about the investigation on the State of New Jersey’s website.

Related posts:

Erin Brockovich

The Brockovich Story, Part 2

CATEGORIZED UNDER: Cancer, select, top-posts
  • Georg Schoen

    I use to ask people stuck in that fallacy,

    whether they know what a frog does, if he hasn’t

    caught a fly for ten minutes?

    Usually they answer: No.

    reply: He will start to catch flies which aren’t there.

    • Guest

      Great comment! I hope I can rememver it.

      • linda518

        uptil I looked at the receipt for $5225, I didnt believe …that…my neighbours mother was really erning money parttime on-line.. there friends cousin haz done this for only ten months and resantly cleared the dept on there villa and purchased Renault 5. we looked here, jump15.comCHECK IT OUT

    • Ernest Barker

      Great comment, I only hope I can remember it!

  • JonFrum

    ” Their actions had been irresponsible and caused fear and unending agony
    among people who will always wonder why their children got sick.”

    Good God. Caused fear? The companies released waste around their plants. The cause of the fear was not the waste – it was environmentalists working the nation into a fevered paranoia over environmental cancers. Millions of people worked in factories through the 20th centuries, and were exposed to far higher concentrations of potential toxins than the people in the surrounding communities ever did.

    The writer goes to the trouble to explain the irrationality of the cancer cluster belief, and then goes on to sanction it with it kick in the general direction of the evil corporations. Which just encourages the same kind of paranoid thinking that caused the problem in the first place.

    The truth is that this is extremely patronizing. “Oh you poor stupid things…. you’re too stupid to understand that you’re making up the connection between waste products released into the environment and cancer that doesn’t exist, so the companies should pay you for the pain your limited wit causes you.” .

    • guest

      Even if environmentalists are wrong about some of the cancers, it doesn’t negate the irresponsibility and selfishness of the corporations, which are polluting the environment
      and the contributing to the die off of innumerable species. That affects us all adversely in the long run. In that sense then, I think that MORE
      corporations owe money for the damage they have caused.

      • Buddy199

        If it can actually be proven not just assumed. Lawyers are great at fudging the difference before gullible, hand picked juries.

  • Dan Meyers

    “There was no biological explanation for why male and female fetuses would respond differently to the carcinogens. If limiting the analysis to girls hadn’t uncovered an association, would the next step have been to distinguish between those with brown hair and blond?”

    Would it be fair to view skeptically the results of clinical and observational studies that distinguish between male and female results with out explaining even a possible mechanism for the difference? The abstract for the study linked below found a correlation between carbohydrate consumption and colon cancer for women and a correlation between carbohydrate intake and rectal cancer in men. To paraphrase (perhaps unfairly) the abstract, “There has been conflicting data regarding carbohydrate consumption and colorectal cancer, maybe we need to control for fiber. Nope, we didn’t find what we were looking for but if we parse the data enough we can find some correlations we were never looking for.” If you have time to read over the abstract tell me if I’m being unfair or not.


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Fire in the Mind

Whether a subtle new pattern shows up in an experiment on the Higgs boson, an epidemiological report about a suspected cancer cluster, or a double-blind trial purporting to demonstrate ESP, it can be maddeningly difficult to distinguish between what we see and what we think we see. "Fire in the Mind" takes a look at the big questions behind today’s science news.

About George Johnson

George Johnson writes about science for the New York Times, National Geographic Magazine, Slate, and other publications. His nine books include The Cancer Chronicles: Unlocking Medicine's Deepest Mystery (August 2013), The Ten Most Beautiful Experiments, A Shortcut Through Time, and Fire in the Mind. He is a winner of the AAAS Science Journalism Award and has twice been a finalist for the Royal Society science book prize. Co-founder and director of the Santa Fe Science Writing Workshop, he can be found on the Web at Twitter @byGeorgeJohnson.


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