News

There may be a good reason why Satan takes the form of a snake in the biblical story of Adam and Eve in the Garden of Eden.

A new study suggests that people are biologically predisposed to learn quickly to fear snakes - a defensive mechanism probably rooted in evolution.

"Snakes would have been threats that we encountered often and in many areas of the world ... throughout the course of human evolution," said one of the researchers, Vanessa LoBue of the University of Virginia.

Today, however, people are seldom exposed to venomous serpents - especially in early childhood, when fears are normally learned and become ingrained.

"We wanted to know whether preschool children, who have much less experience with natural threats than adults, would detect the presence of snakes as quickly as their parents," said Dr. LoBue. "If there is an evolved tendency in humans for the rapid detection of snakes, it should appear in young children as well as their elders."

For the study, children and adults were individually asked to find an image of a snake on a computer screen filled with pictures of relatively harmless entities such as flowers, frogs and caterpillars. Then they were given instructions to pinpoint the harmless object on a touch screen full of snakes.

The results revealed that "parents and their children identified snakes more rapidly than they detected other stimuli, despite the gap in age and experience," the researchers said in a statement released with the study published in the journal Psychological Science.

Dr. LoBue said the study might help explain why snake phobias are so common. "Snakes are often used in human history, at least in literature, as a symbol of evil," she said in an interview.

"It is kind of strange that so many people are afraid of snakes yet they don't really encounter them very often any more."

AIDS-FIGHTING GENE

A team of Canadian and U.S. researchers has discovered a gene that can apparently block the spread of HIV, the virus that causes AIDS.

"The gene is part of the body's natural ability to fight infections from viruses," said Stephen Barr, a researcher at the University of Alberta and lead author of the study.

Viruses normally invade specific cells where they replicate, then the new virus particles break out to infect more cells in the body. The newly discovered gene is believed to have the ability to keep the viruses trapped inside the infected cells so they can't spread. But, for unknown reasons, the gene is not functioning properly in people infected with HIV.

"Our goal is to figure out why this gene doesn't work in HIV patients," said Dr. Barr, whose study was published in the journal Public Library of Science Pathogens. He added that the research could lead to new AIDS treatments.

ptaylor@globeandmail.com