Don't Wear the Juice 1: Dunning-Kruger's Effect

Often, the loudest voices, the best circulated ideas, and the boldest assertions are from people who know little or nothing about what they're talking about.

December 30, 2019
ISG Team


Back in 1995, McArthur Wheeler robbed two Pittsburg banks in brazen hold-ups. Wheeler, an imposing man, wore no mask as he pulled a gun on the tellers and demanded money. He knew something they did not. Lemon juice, as it turns out, is an ingredient in 'invisible ink'.

Imagine Wheeler's surprise when the police knocked on his door a little after midnight after having broadcast his picture all over the evening news. As the Police told him he was under arrest for the bank robberies, he responded with confusion, saying "...But I wore the juice."


McArthur Wheeler. He wore the Juice.
Don't wear the juice.

Wheeler's case caught the attention of Cornell Psychology professor David Dunning, who, with help from graduate student Justin Kruger, formed a series of tests. They quizzed students on some basic topics, and asked them to do two critical things:

  • Guess how well they did
  • Rank themselves against their peers

Before we discuss what happened with the students, let's go back to Wheeler.

Wheeler thought that because Lemon Juice made ink disappear, that it would hide his face from the camera. He even claims to have tested it using a polaroid camera, and indeed, blurry photos were found that the police couldn't explain. Wheeler claimed that he tried putting lemon juice on his face and using the polaroid to ensure his theory was correct. He took the resulting blurry photo as proof-positive that he was correct and could indeed just walk right in and rob a bank.

This is where Wheeler and Dunning-Kruger's experiments begin to intersect.

The students tested by Dunning and Kruger who did the worst estimated themselves to be among the smartest... in the upper intellectual third. Dr. Dunning expected this, but not to the degree they observed. On the other hand, those who did well on the tests assessed themselves as slightly less competent than they actually were.

In other words, they were aware of what they didn't know whereas those who failed spectacularly didn't know what they didn't know.'

Back to Wheeler one last time. He failed to recognize a few critical things:

  • He didn't really know what was happening with lemon juice and invisible ink. He just assumed it made stuff invisible.
  • He didn't know how cameras worked or that there were different methods that cameras use to capture images.
  • He assumed that all he had to defeat was the cameras and he walked around showing his face to people who could later pick him out of a line up.

The False Expert

Let's do a mental exercise: prepare to answer the question "what is the perfect car?"

Hold that thought.

Any time you see someone purporting expertise, it's critical to begin asking yourself about their relevance (why does their material matter to you? Is the information current?), context (does their experience have any similarities to the situations you're likely to face?) and finally, their ability to convey the material.

The expert in society often draws from a narrow channel of expertise, and they grow confident as they progress through their field. When asked about a peripheral topic, we often see these experts demonstrate "unconscious incompetentence". For example, we've discussed some examples in the past of well-credentialed professionals who were confidently wrong. From Navy SEALs claiming to be urban survival experts (and giving verifiably false information) to Tactical schools teaching woefully underprepared students bad techniques. We've talked about police trainers who can only be described as 'entirely wrong', and preppers whose misguided attempts at preparedness led to car firesor the insistence that tampons are good for wound packing.

This trend spans the gamut, and just like Dunning and Kruger observed, the loudest, most insistent voices were often the most patently incorrect. That's fine if it's someone selling you a car, but the business we're in is keeping ourselves, our loved ones, and our communities alive... not buying into an image or old boy's club.

Because of this, we want to encourage the ISG community to invest their trust discernibly. Ask yourself in any given situation, the following:

  1. Does the expert have an agenda? The answer is "yes" in nearly every case. The agenda is "appeal to the masses, make money". Then ask yourself: "Am I the masses?" If you're here, you're probably not. You might notice we're not selling anything.

    Supporting us is an option, not a requirement. We're willing to pay to bring this information, because we actually want you to cultivate resiliency.
  2. Does the expert demonstrate competence, or do they tout credentials? In a meritocracy, credentials are a useful guide, not a hard-and-fast verification of contextual relevance or knowledge.
  3. Does the expert admit the limits of their knowledge and seek it elsewhere? Are they capable of accepting feedback or considering second opinions?
  4. Do the instructors cultivate an image for themselves that's rooted in clichés? If so, you're probably dealing with a marketing ploy.
  5. Does the instructor try to ensure they never do anything controversial? If so, are they defaulting to socially acceptable material or presenting harsh realities?
  6. Has the instructor passed their expiration date? While we should always respect and honor those who came before us, that doesn't mean that their information is current best practice.

Information is so readily available that anyone with an internet connection can make themselves a convincing authority on any subject. To make matters worse, there's a robust culture of 'personality cults' in the training industry... often at the hands of the people who really don't have any real relevance, any underlying philosophy that guides their approach, or have a utterly monochromatic approach to their knowledge... that is to say: they really only know one thing and make educated guesses at the rest.

So, about the perfect car: What is it?

Did you have one in mind? Did you say 'it depends'? or did you say 'Car, or automobile in general?' and ask 'what is the end goal?'

If someone can answer reflexively, there's a good change they're not thinking through the problem. The difference between the confidence a neophyte has in their opinion and the confidence an expert has in theirs is simple:

The experts ask the hard questions before giving their answer.

The confidence to simply spout off an answer requires a narrow frame of mind that comes from inexperience, or experience that is very specific. Unless you live a life identical to that person, their experience might simply be irrelevant. Ask those hard questions.


Guys, we're not the only game in town and we know you're going to get information from other people. That's good and we want you to... but be careful who you listen to. You should look for false confidence just as you would proficiency. Learn to recognize it and, above all, avoid it. You should be suspicious of sources of information that don't (or can't) demonstrate exactly what they're talking about. Question the experts. As Colin Powell once said, often times, they possess more data than experience.

Finally, check that ego. A solid practice is to think back on yourself before the last major learning experience you had and consider how much you've developed. If you then consider how much future experiences will change your perspective, it's easy to remember that you've always got more to learn.

Don't wear the juice.

Think for yourself and pick your peers, instructors, and mentors wisely. If they're not someone you'd like to become, take it on the arches and find a better source of information.

For more on how to apply this to emergency management, check out Part II.


ISG Team

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