It All Started With "Explosive" Diarrhea

Dunning- Kruger took over from there

Nextdoor is an app that brings neighborhoods together. It’s where communities connect to greet newcomers, exchange recommendations, and stay informed about the latest local news. This is how Nextdoor describes itself, and it is sometimes useful for getting recommendations for dog sitters and mechanics or bitching about property tax reassessments. Crucially, it’s fairly good about keeping politics off limits too. Even so, it should be, and maybe is, a cleverly designed psychological study. And the result is all there to see in my recent Nextdoor adventure related to a possible foodborne illness from a Thanksgiving turkey dinner.

Personally, I wouldn’t have felt compelled to share the excruciating details of my toilet fireworks with neighbors on Nextdoor but nobody is more anxious to jump into a discussion about explosive diarrhea than environmental health professionals like me. Food safety is one of our primary responsibilities and investigating the epidemiology of possible foodborne illnesses, which sometimes hit the jackpot with projectile vomiting too, is a common responsibility. When I saw the initial post on Nextdoor I was both sympathetic to the explodees — foodborne illness is a miserable experience — and a bit concerned about the immediate assumption that a particular restaurant was the source. I actually tried to contact environmental health in our jurisdiction, but all offices were closed (it was Black Friday) presumably until Monday. So, I shared a “suspected foodborne illness” reporting form I found online with the mob, and suggested, a time or two, that jumping to conclusions about the source of the illness — the local restaurant — wasn’t justified. After all, an actual outbreak can ruin a restaurant’s business and the source is rarely clear absent a thorough investigation. Worse, half-assed speculation rarely gets retracted when the real story is eventually confirmed.

Since the explosions-in-question had an onset-of-symptoms about 10 hours after the accused meal I explained that this would be too short a time for the most common foodborne illnesses, Salmonella and norovirus, but could be consistent with foodborne intoxications. The mob, however, was already settling into their own ideas.

Nextdoor feeding frenzies give no quarter. One person, who obviously doesn’t understand all-caps means “emphasis here,” accused me of trying to start a panic by suggesting it’s Mad Cow disease (bovine spongiform encephalopathy). My favorite was the person who said, “I strongly disagree with your ‘expertise’,” putting her three presumed foodborne illness experiences and “food science study” down as a challenge. I do understand what putting “expertise” in quotes means.

Now I hadn’t given a personal detailed background in my previous posts except to say that I have 40+ years’ experience in public health with foodborne illness investigations — not enough to sway this person. I’m fairly certain explaining that I have an undergraduate degree in biology (including 400-level classes in bacteriology and parasitology), a master’s degree in public health (two graduate classes in epidemiology and epidemiology statistics), forty years of environmental health experience (including overseeing the food safety program in a suburban- Chicago County with around 3,000 food service venues) and have participated in maybe 100 suspected foodborne disease outbreak investigations over my career wouldn’t have dampened her spirit either.

But here’s the key thing. I did not, nor would I ever consider myself an expert in foodborne disease. I likely know 100 times more than this person and the others jumping to conclusions about this circumstance, but I have the capacity to recognize that many others, including sanitation experts and epidemiologists formerly on my own staff, know 100 times more than me. Maybe even someone watching this ridiculous Nextdoor conversation was so much smarter than me that he/she had enough sense not to get involved.

At any rate, this has a name - the Dunning- Kruger effect. Brittanica defines as follows- Dunning-Kruger effect, in psychology, a cognitive bias whereby people with limited knowledge or competence in a given intellectual or social domain greatly overestimate their own knowledge or competence in that domain relative to objective criteria or to the performance of their peers or of people in general. According to the researchers for whom it is named, psychologists David Dunning and Justin Kruger, the effect is explained by the fact that the metacognitive ability to recognize deficiencies in one’s own knowledge or competence requires that one possess at least a minimum level of the same kind of knowledge or competence, which those who exhibit the effect have not attained. In other words, recognizing your incompetence in some subject matter requires that you possess some level of competence in the first place. Or you could follow the old adage, better to say nothing and be thought a fool than to speak and remove all doubt. Another component of the Dunning- Kruger effect, which is not nearly as entertaining or maddening, is that the more competence one has in a subject, the more likely he/she/etc. are to recognize their limitations in that subject.

Interestingly, the studies establishing the Dunning-Kruger effect date only back to the late 1990’s and early 2000’s. Perhaps it took the internet and social media like Nextdoor to expose this imminent threat to humanity, but I’ll bet we’ve all known somebody from the beginning. One of my favorite and most common Nextdoor posts in our neighborhood is “does anybody know what kind of snake this is” with an accompanying photo. It could be a 40’ anaconda eating a cow or an earthworm but inevitably and without fail someone will say with all the confidence in the world…..“copperhead.” Sometimes Dunning-Kruger can be entertaining.

The restaurant in question will not find it entertaining at all if the source of this illness is not related to their Thanksgiving offerings. Some posts have reported eating the offending turkey meal without becoming ill, and the ratio between sick and well individuals for any particular food is a key part of an investigation. The mob has discounted this tidbit already. The place has already been tarred and feathered, drawn and quartered and burned at the stake by idiotic speculation. That’s bad enough for any individual or business, but let’s not forget the terrible loss of human lives that incompetent advice, some horribly purposeful, has cost during COVID — hundreds of thousands after vaccines were widely available. That’s the side of the Dunning-Kruger effect that’s tragic, and I’m afraid I don’t see any end in sight. Then again, what do I know about psychology — explosive diarrhea (preferably with at least a little projectile vomiting) is my game.