In 1963, at the start of the academic year, Robert Rosenthal and Lenore Jacobson gave children at a primary school in America an IQ test.
The test identified the potential academic whizz-kids.
The teachers were then told which kids had scored in the top 20%.
But they were also told that they couldn’t tell the kids they had done well or treat them any differently because of it.
The teachers would also be watched to make sure they did as they were told.
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