Ignoring the debunks that turn his argument to mush, he wrote:-
"Cognitive dissonance is a psychological phenomenon which refers to the discomfort felt at a discrepancy between what you already know or believe, and new information or interpretation. It therefore occurs when there is a need to accommodate new ideas, and it may be necessary for it to develop so that we become "open" to them. Neighbour (1992) makes the generation of appropriate dissonance into a major feature of tutorial (and other) teaching: he shows how to drive this kind of intellectual wedge between learners' current beliefs and "reality".
Beyond this benign if uncomfortable aspect, however, dissonance can go "over the top", leading to two interesting side-effects for learning:
■ if someone is called upon to learn something which contradicts what they already think they know — particularly if they are committed to that prior knowledge — they are likely to resist the new learning. Even Carl Rogers recognised this. Accommodation is more difficult than Assimilation, in Piaget's terms.
■ and—counter-intuitively, perhaps—if learning something has been difficult, uncomfortable, or even humiliating enough, people are less likely to concede that the content of what has been learned is useless, pointless or valueless. To do so would be to admit that one has been "had", or "conned"."
Here is another definition of that level of stupidity.
"The Dunning–Kruger effect is a cognitive bias in which unskilled people make poor decisions and reach erroneous conclusions, but their incompetence denies them the metacognitive ability to appreciate their mistakes."