Researchers have found that sleep not only boosts mind power but also helps reduce racial and gender biases. A study suggests that conditioning exercises prior to and during sleeping periods can help alter deeply rooted memories such as prejudices and beliefs. Some people are not even aware that they possess such thoughts and behaviors.

"The implicit memory is information we store but don't know we have it, and that information is used when we make decisions," says Ken Paller, psychology professor and director of the cognitive neuroscience program at Northwestern University. "Even though we might not even agree with the stereotype—that knowledge of the stereotype is something we've encoded in our brain."

The research team then conducted an experiment that involved 40 white men and women who were 18 to 30 years old. The participants were initially asked to complete the Implicit Association Test, or AT, which identified their baseline racial and gender biases. The scientists then reversed the common stereotypes and exposed the participants to the altered associations. For example, since black people are commonly stereotyped to have negative behavior, and females are rarely associated with science, the researchers conditioned the participants to think otherwise.

The blacks were linked to keywords such as "honor," "smile" and "cheer" while females were associated with scientific words. The participants were then given devices and were asked to press the button every time the correct association appears on the computer screen. The participants heard particular sounds every time they hit the correct "black-good" and "female-science" pairings. After the trainings, the participants were then asked to take a nap for 90 minutes. The distinct sounds associated with the learned pairings were then played softly while the participants were asleep.

The results of the study published in the journal Science show that the participants exhibited a higher than 50 percent drop in gender biases after they woke up; however, racial prejudices remained unchanged. "These biases are well-learned," explained Dr. Xiaoqing Hu, lead author and postdoctoral researcher at the University of Texas at Austin. "They can operate efficiently even when we have the good intention to avoid such biases. Moreover, we are often not aware of their influences on our behavior."

The scientists tested the participants after a week and, although the results declined by 20 percent, it was found that their biased behaviors continued to be low.

"It is somewhat surprising that the sleep-based intervention could have an impact that was still apparent one week later," stated Hu. "The usual expectation is that a brief, one-time intervention is not strong enough to have a lasting influence."

Dr. Gordon Feld and Dr. Jan Born, psychologists at the University of Tubingen in Germany comment that while the research is encouraging, testing people while asleep and without willful consciousness makes the participants vulnerable to suggestion and may impose ethical issues.

Photo: Pedro Ribeiro Simões | Flickr