The seductive allure of anti-scientific conspiracy theories among otherwise rational people

By William Hausdorff

The rejection of climate change science

Many political observers linked President Trump’s decision to pull the US out of the Paris global warming agreement to his own psychology. The French newspaper Le Monde considered it a manifestation of his “rĂ©gression infantile.”  The Washington Post characterized the rationale Trump gave—the rest of the world is using the treaty to take advantage of the US—as a “visceral expression” of his own personal dog-eat-dog world view.  Such a psychological interpretation is attractive because there is little alternative: Trump seems unwilling and frankly, mentally incapable of decision-making based on understanding even slightly complex issues.

Unfortunately, the focus on Trump’s deranged psychology effectively portrays him as “the decider-in-chief.”  Yet, like most other decisions he makes, this was not an outlier activity of our disturbed President making policy decisions in his bathrobe in front of his TV.  

As noted by our own Professor Dorf, withdrawal from the agreement is precisely what the Republican party as a whole has been demanding One needs to look no further than the cheering and giddiness of VP Pence, Speaker of the House Ryan, and Senate Majority Leader McConnell the day Trump announced his decision. Put another way, if the Republican Party were against this, it would have never happened.  

Although I disagree with their politics, there’s no question that much of the leadership of that party is comprised of well educated, rational people.  What are the deep-seated beliefs that compel them to disregard the overwhelming scientific consensus? The simplest explanation for their behavior is that they have none, other than to follow what their gas and oil industry sponsors, especially the Koch brothers, have paid for.

But what about approximately 1/3 of American population—the vast majority of whom don’t receive financial support from the fossil fuel industry—who remain unwilling to accept that climate change is manmade? I don’t think most are just dumbly “following the Party line.” Yes, they are nourished by the steady bombardment (mixed metaphor intended) of packaged industry-funded disinformation by Fox News, the media arm of the Republican party.  But this disinformation is tapping into a deep-seated resentment of others--the scientific elite, foreigners—telling them what they should think.

Just uneducated, marginal populations?

It remains tempting to ascribe adherence to obviously bogus conspiracy theories as a characteristic of relatively uneducated populations. For example, resistance to polio immunization efforts in what are the last redoubts of wild polio in the world, rural areas of Pakistan and in northern Nigeria, has been fueled by the belief that there is a Western/Christian plot to sterilize largely Muslim populations.  Scholarly articles and even entire books devoted to explaining this resistance don’t identify any potent pseudo-scientific arguments whatsoever.  Rather, they highlight deep-rooted local hostility to the notion that the federal government and its international backers are in any way acting in the best interests of the population.

Conspiracy theories of an international plot are easily fueled when the same Western powers that bankroll the eradication efforts in Pakistan are those that repeatedly target those communities with US drone attacks (and attendant civilian casualties).  The eradication program was particularly set back by the Obama administration’s decision to use immunization health care workers to locate and eliminate Osama Bin Laden.

Within the US too, there exist culturally marginalized populations that are particularly susceptible to similar conspiracy theories.  One example is the very recent outbreak of measles in Somali children in Minnesota, comprising at least 76 cases and several hospitalizations and counting.  This was due to plummeting measles-mumps-rubella (MMR) vaccination rates that followed false assertions by a professional anti-vaccine activist of scientific evidence of a link between MMR and autism. 

It’s not just an issue of education

Is this just because these particular communities are relatively uneducated?  A former colleague from Nigeria told me he had been puzzled by the public endorsement of these preposterous anti-polio vaccination arguments by a respected Nigerian scientist.  He then visited the professor, whom he knew quite well, who (privately) admitted that there had been pressure on him to lend scientific cover for the real issue: hostility to a Federal government proposal that would increase taxes on Northern landowners.  The polio eradication program was the target since it was clearly identified as a federal government priority.  The cynical manufacture of conspiracy theories at the service of financial gain is not just the province of the Republican Party.

About 15 years ago, I was trying to fathom how South Africa’s then-President Thabo Mbeki, by all accounts a very intelligent individual, could have categorically refused to accept that HIV causes AIDS.   The tragic consequence was his multi-year prohibition of antiretroviral drug programs in his country, a ban estimated to have resulted in over 300,000 deaths. 

The explanation of an American public health official I spoke with at the time served as an epiphany of a sort: he wondered whether Mbeki’s belief could be traced to a mindset shaped by living under more than 40 years of apartheid in his country.  During apartheid, the white power establishment repeatedly told blacks in no uncertain terms what they could or could not think.  He speculated—almost sympathetically--that Mbeki felt the indisputability of the HIV/AIDS connection to be just another example.

This is a fundamental characteristic of any conspiracy theory:  it is unfalsifiable.  In other words, for Mbeki, it simply didn’t (and still doesn’t) matter how many excellent scientific studies are conducted that refute the original hypothesis.  There was literally no information or data that would change his mind.

The appeal of anti-scientific conspiracy theories in liberal populations

Lest we think that that the outright rejection of scientific reality is the province of angry nativist populations, let’s reflect on the persistence of these same bogus beliefs even in mainstream, well-educated, political liberal areas, depressing vaccination rates and resulting in disease outbreaks, such as at Disneyland a few years ago. 

Unlike the polio and sterilization story, the spurious linkage between measles vaccination and autism was not ridiculous on its face.  For example, diagnoses of autistic spectrum behavior are generally first able to be made around 18 months of age, when some childhood vaccines, such as MMR, are given.  Given this temporal association, and because we still don’t really understand the causative mechanisms behind autism, it was not ridiculous to hypothesize some kind of connection between autism and MMR, and it was important to explore this.

Similarly, it is well known that mercury can act as a neurotoxin, so it might seem conceivable that the minute amounts of mercury-containing thimerosal, once added as a preservative to some vaccines (not measles or MMR, however) to prevent bacterial contamination, might be associated with the neurological condition of autism. 

A more recent hypothesis is that multiple antigens (“combination vaccines”) given at one visit might somehow “overload” the immune system, so it’s better to space out the visits.  In the real world, additional visits to the clinic means a considerable portion of the children will end up not getting their vaccines on time (i.e., prior to the peak incidence of the disease they are trying to prevent), or at all. 

Each of the hypotheses, with their surface appeal, has since been extensively investigated by other researchers with multiple well-designed studies and analyses, using myriad methodological approaches.  There simply is no credible evidence showing any link between autism and MMR or thimerosal, or with the numbers of vaccines given.

One underlying belief responsible for the enduring appeal of anti-vaccine theories, despite being debunked on their scientific merits, is that natural exposure to pathogens has its benefits, and that there might be a trade-off by preventing some diseases.  For example, an individual who has contracted measles or chicken pox (varicella) as a young child and recovered will generally be naturally protected against the disease as an adult, when it is much more likely to cause serious health problems.

The reality of vaccine-preventable diseases

However, in contrast to hypothetical concerns noted above, the diseases that are targets of immunization programs are KNOWN to have the potential to lead to severe complications or death, even in children.  With measles, for example, historical data from the pre-vaccine era in the US indicated that about 10% of cases ended up in the hospital (perhaps similar to the current proportion in the Minnesota/Somali epidemic). 


Of the hospitalized cases, 10% developed encephalitis and 1% died.  Cervical cancer, preventable by HPV vaccination, is real—anyone with a family member who has been given a diagnosis knows it can be terrifying, even if caught early.  Meningococcal meningitis, in which a healthy adolescent can go from active to dead in less than 24 hours, is real.  Pertussis is horrible—just watch a very young baby with whooping cough.  No parent wants to see their child with rotavirus disease being hauled off to hospital for emergency rehydration. 

Even the chicken pox story becomes complicated, because in addition to rare, severe disease in children, the same virus can be responsible for shingles later in life (herpes zoster).  

Sadly, groundless anti-vaccine arguments continue be propagated by liberals such as the environmentalist Robert Kennedy Jr, and even by the professional skeptic Bill Maher (as I’ve recently learned, to my considerable dismay).   Assuming it’s not purely cynical, what are their underlying beliefs that allow them to disregard the overwhelming medical consensus?

When pressed on the topic, Maher explained,

“it’s like, ‘You know what? Shut the fuck up and let me take every vaccine that Merck wants to shove down my throat.’''

Of course, it is not unreasonable to assume that large pharmaceutical companies, which currently supply the vast majority of vaccines used in the industrialized world, are inherently driven by the prospect of selling more vaccines to more people.  Furthermore, some pharmaceutical companies are not always responsible social actors. 

However, to go from this perspective to assuming that unnecessary, unsafe vaccines are being recommended for widespread use across the population for the purpose of enriching corporate coffers requires a conspiracy of stunning breadth.  Virtually everyone must be participating—not just the pharma companies themselves, not just academic scientists getting corrupted by pharma, not just government officials (FDA, CDC), not just international public health officials (WHO), but also the vast majority of physicians. (Disclosure:  I have worked in the vaccine field for more than 25 years, including for the US CDC and two large vaccine developers).

Whether "genuine" or cynically manufactured, for conspiracy theories to persist in the face of overwhelming scientific evidence, they likely also possess a visceral appeal.  Until we understand and acknowledge that appeal, it is unlikely their believers will listen to us about the science.  As the cartoon character Pogo used to say, “We’ve met the enemy and he is us.”