Why You Think You Know Things That You Really Don't

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At first blush, it would seem that not knowing something would make us correspondingly uncertain. Instead, however, it sometimes has the opposite effect, with people not only professing to know something, but even making up an explanation and holding fast. Here's why — and how — that works.

Psychologist and Cornell University professor David Dunning has written an article for Pacific Standard on the psychology of ignorance, misinformation, and certainty. You may already be familiar with Dunning and his work from the eponymously named Dunning-Kruger effect, the phenomenon which is responsible for making those with expert-level abilities underestimate their skills and knowledge, while at the same time allowing those who know the least to overestimate their own skills.


Lest we think of this purely as a phenomenon that impacts only other people, though, Dunning offers this note of caution: "Because it's so easy to judge the idiocy of others, it may be sorely tempting to think this doesn't apply to you. But the problem of unrecognized ignorance is one that visits us all." And, sometimes even when we have the overarching concepts correct, the details can still bedevil us — and that has some serious implications for how we teach science.

Here Dunning explains just how this phenomenon has played out in the teaching of evolution:

This purpose-driven misconception wreaks particular havoc on attempts to teach one of the most important concepts in modern science: evolutionary theory. Even laypeople who endorse the theory often believe a false version of it. They ascribe a level of agency and organization to evolution that is just not there. If you ask many laypeople their understanding of why, say, cheetahs can run so fast, they will explain it's because the cats surmised, almost as a group, that they could catch more prey if they could just run faster, and so they acquired the attribute and passed it along to their cubs. Evolution, in this view, is essentially a game of species-level strategy.

This idea of evolution misses the essential role played by individual differences and competition between members of a species in response to environmental pressures: Individual cheetahs who can run faster catch more prey, live longer, and reproduce more successfully; slower cheetahs lose out, and die out—leaving the species to drift toward becoming faster overall. Evolution is the result of random differences and natural selection, not agency or choice.

But belief in the "agency" model of evolution is hard to beat back. While educating people about evolution can indeed lead them from being uninformed to being well informed, in some stubborn instances it also moves them into the confidently misinformed category. In 2014, Tony Yates and Edmund Marek published a study that tracked the effect of high school biology classes on 536 Oklahoma high school students' understanding of evolutionary theory. The students were rigorously quizzed on their knowledge of evolution before taking introductory biology, and then again just afterward. Not surprisingly, the students' confidence in their knowledge of evolutionary theory shot up after instruction, and they endorsed a greater number of accurate statements. So far, so good.

The trouble is that the number of misconceptions the group endorsed also shot up. For example, instruction caused the percentage of students strongly agreeing with the true statement "Evolution cannot cause an organism's traits to change during its lifetime" to rise from 17 to 20 percent—but it also caused those strongly disagreeing to rise from 16 to 19 percent. In response to the likewise true statement "Variation among individuals is important for evolution to occur," exposure to instruction produced an increase in strong agreement from 11 to 22 percent, but strong disagreement also rose from nine to 12 percent. Tellingly, the only response that uniformly went down after instruction was "I don't know."


You can read the whole essay — where Dunning explains some of the many ways that the mind has supplied us with fictitious facts, and an accompanying certainty to go along with it — over at Pacific Standard.

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