The more you sleep, the less sexist and racist you become

It may sound like something out of a Brave New World, but it turns out scientists can manipulate our unconscious biases while we sleep.

Researchers from Northwestern University in Chicago gave people "counter bias" training, which involves pairing pictures of faces with words that break down stereotypes - so women's faces were paired with words like "science" and black faces with words like "sunshine".

The subjects then had a 90-minute nap while scientists played audio cues designed to trigger the memory of the bias exercises from earlier.

The results, published in Science, found that the both after the nap and a week later, participants were less biased towards black people and women.

The results could be very useful for challenging unconscious bias in training for people in positions of authority, like judges, or people making hiring decisions.

However, the study's findings have ethical implications. The test could also work the other way, much like subliminal advertising or brainwashing.

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