Where in the book "Lies My teacher Told Me" it states something about "Cognitive Dissonance"?

Answer 1

Cognitive dissonance is a well-known psychological principle. It suggests that it is very difficult to behave in a way contradictory to your beliefs - eventually one or the other has to give and you stop doing whatever it is you don't believe in, or your beliefs start to change to justify your actions so they're 'okay'.

This come up in the book "Lies My Teacher Told Me" when the author is discussing textbook coverage of Columbus' voyage:

After arriving in the 'New World', Columbus discovered natives who knew where gold could be found. Columbus desperately needed a big find like that to make his voyages seem worthwhile. So he began using some of the most horrific means imaginable to extract every ounce of gold from the natives, ultimately being responsible for the death of something like 99% of the human population on one island.

Obviously, most normal people couldn't stomach such measures outright. But cognitive dissonance and inventive thinking quickly provided a solution: natives were 'primitive' and 'savage', and according to some people even 'soulless'. Wiping them out was therefore no more a crime than pulling weeds from a garden.

Sad, really, when you think about it.