The burglar with the lemon juice disguise

I’ve just re-read the classic study “Unskilled and unaware of it” which established that when we’re incompetent at something we’re often so incompetent that we don’t realise that we’re incompetent. I had forgotten that it starts with a wonderful story about an inept bank robber.

In 1995, McArthur Wheeler walked into two Pittsburgh banks and robbed them in broad daylight, with no visible attempt at disguise. He was arrested later that night, less than an hour after videotapes of him taken from surveillance cameras were broadcast on the 11 o’clock news. When police later showed him the surveillance tapes, Mr. Wheeler stared in incredulity. “But I wore the juice” he mumbled. Apparently, Mr. Wheeler was under the impression that rubbing one’s face with lemon juice rendered it invisible to videotape cameras (Fuocco, 1996).

We bring up the unfortunate affairs of Mr. Wheeler to make three points. The first two are noncontroversial. First, in many domains in life, success and satisfaction depend on knowledge, wisdom, or savvy in knowing which rules to follow and which strategies to pursue. This is true not only for committing crimes, but also for many tasks in the social and intellectual domains, such as promoting effective leadership, raising children, constructing a solid logical argument, or designing a rigorous psychological study. Second, people differ widely in the knowledge and strategies they apply in these domains (Dunning, Meyerowitz, & Holzberg, 1989; Dunning, Perie, & Story, 1991; Story & Dunning, 1998), with varying levels of success. Some of the knowledge and theories that people apply to their actions are sound and meet with favorable results. Others, like the lemon juice hypothesis of McArthur Wheeler, are imperfect at best and wrong-headed, incompetent, or dysfunctional at worst.

Perhaps more controversial is the third point, the one that is the focus of this article. We argue that when people are incompetent in the strategies they adopt to achieve success and satisfaction, they suffer a dual burden: Not only do they reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the ability to realize it. Instead, like Mr. Wheeler, they are left with the mistaken impression that they are doing just fine. As Miller (1993) perceptively observed in the quote that opens this article, and as Charles Darwin (1871) sagely noted over a century ago, “ignorance more frequently begets confidence than does knowledge” (p. 3).

This effect has since been named the Dunning-Kruger effect after the authors of the study.

Link to PubMed entry for study.

8 thoughts on “The burglar with the lemon juice disguise”

  1. “Apparently, Mr. Wheeler was under the impression that rubbing one’s face with lemon juice rendered it invisible to videotape cameras.”
    But surely not just to cameras: Kids commonly use lemon juice as a form of “invisible ink,” which only shows up on paper when it’s heated. And if lemon juice can make ink invisible, why wouldn’t rubbing it on your face make you invisible?
    This is why science education is so important….

    1. You don’t need science education for this one. Most 3rd graders could come to the conclusion rubbing lemon juice on you won’t make you invisible to a video camera. This guy is an idiot. You don’t think he had science education through his schooling? You can’t teach the stupid out of people.

  2. “It’s not what you don’t know that will get you in trouble; it’s what you know that ain’t so.” Mark Twain

    Knowing is an illusion IMHO! You never really know anything…it’s the feeling of knowing. Knowing you are in love or hate someone is all about emotions. It applies to all aspects of human belief. Humans = creatures of emotion; not logic…someone said… maybe it was Andrew Carnegie?

  3. @Geoff: Wheeler believed that the lemon juice would cause his face to be blurred in the security camera footage.

    While the lemon juice would cause diffraction (which is certainly what Wheeler was going for), it would be on a very minor scale and the effect probably wouldn’t be noticeable on a security camera.

    It was not poor logic that doomed Wheeler; it was a lack of understanding of the effect he was attempting to use.

    And maybe we don’t want more science education…if Wheeler had taken Physics, another criminal might be walking free today! haha

    1. and if no one took physics, then all criminals might be walking free today! haha.

      I guess better sorry than safe is your motto?

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