Friday, April 16, 2010
Never has a human population been found that has no racial stereotypes. Not in other cultures or far-flung countries. Nor among tiny tots or people with various psychological conditions.
Until now. Children with Williams syndrome, a rare genetic disorder that makes them lack normal social anxiety, have no racial biases. They do, however, hold the same gender stereotypes other children do, said study researcher Andreas Meyer-Lindenberg of the University of Heidelberg in Germany.
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Normally, children show clear preferences for their own ethnic group by the age of 3, if not sooner, other research has shown.
And, indeed, the children in this study without Williams syndrome reliably assigned good traits, such as friendliness, to pictures of people the same race as themselves. When asked something negative, such as "which is the naughty boy," they overwhelmingly pointed to the other race.
Children with Williams syndrome, however, were equally likely to point to the white or black child as naughty or friendly.
While this study was done with white children, other research has shown that blacks and people of other races also think more highly of their own, Meyer-Lindenberg told LiveScience.
"The whole concept [of social anxiety] would be foreign to them," he said.
They will put themselves at great peril to help someone and despite their skills at empathy, are unable to process social danger signals. As a result, they are at increased risk for rape and physical attack.
Nature or nurture?
While the first human population to demonstrate race-neutrality is missing critical genes, "we are not saying that this is all biologically-based and you can't do anything about it," Meyer-Lindenberg said.
"Just because there is a genetic way to knock the system out, does not mean the system itself is 100 percent genetic," he said.
The study does show, however, that racism requires social fear. "If social fear was culturally reduced, racial stereotypes could also be reduced," Meyer-Lindenberg said.
Despite their lack of racial bias, children with Williams syndrome hold gender stereotypes just as strongly as normal children, the study found. That is, 99 percent of the 40 children studied pointed to pictures of girls when asked who played with dolls and chose boys when asked, say, who likes toy cars.
The fact that Williams syndrome kids think of men and women differently, but not blacks and whites, shows that sex stereotypes are not caused by social anxiety, Meyer-Lindenberg said.
This may be because we learn about gender within "safe" home environments, while a different race is usually a sign of someone outside our immediate kin. (Studies to test this explanation, such as with racially-mixed families, have not yet been done.)
Racial biases are likely rooted in a general fear of others, while gender stereotypes may arise from sweeping generalizations, Meyer-Lindenberg said. "You watch mother make the meals, so you generalize this to everyone female."
Due to the present study, we now know that "gender and race are processed by different brain mechanisms," Meyer-Lindenberg said, although those involved in gender are less understood.
Previous work has shown that in the brains of people with Williams syndrome, the amygdala — the emotional seat of the brain — fails to respond to social threats. While the amygdala itself is functionally normal, it is misguided by the pre-frontal cortex — the executive of the brain — to block all social anxiety.
This system is now thought to underlie racism, but it seems uninvolved in the formation of sex stereotypes.
Meyer-Lindenberg and colleagues are now using brain imaging to get a clearer picture of how racism and sexism are differentiated in the brain. The present study was published in the journal Current Biology.
Thursday, April 8, 2010
People who have "near-death experiences," such as flashing lights, feelings of peace and joy and divine encounters before they pull back from the brink may simply have raised levels of carbon dioxide (CO2) in the blood, a study suggests.
Near-death experiences (NDEs) are reported by between 11 and 23 per cent of survivors of heart attacks, according to previous research. But what causes NDEs is strongly debated. Some pin the mechanisms on physical or psychological reasons, while others see a transcendental force.
Researchers in Slovenia, reporting on Thursday in a peer-reviewed journal, Critical Care, investigated 52 consecutive cases of heart attacks in three large hospitals. The patients' average age was 53 years. Forty-two of them were men.
Eleven patients had NDEs, but there was no common link between these cases in terms of age, sex, level of education, religious belief, fear of death, time to recovery or the drugs that were administered to resuscitate them.
Instead, a common association was high levels of CO2 in the blood and, to a lesser degree, of potassium.
Further work is needed to confirm the findings among a larger sample of patients, say the authors, led by Zalika Klemenc-Ketis of the University of Maribor.
Having an NDE can be a life-changing experience, so understanding its causes is important for heart-attack survivors, they say.