Minds might be 'infantilized,' baroness testifies in House of Lords.

This is your brain.

This is your brain on Facebook.

It's an advertisement you might see someday, if testimony given to the British House of Lords this month is to be believed. In remarks that have stirred up a tempest in the British media and on the Internet, Baroness Susan Greenfield, a neuroscientist at the University of Oxford, warned that the instant feedback and impersonal communication offered by social networking sites could drive human brains and behavior in negative directions.

"As a consequence, the mid-21st Century mind might almost be infantilized, characterized by short attention spans, sensationalism, inability to empathize and a shaky sense of identity," Greenfield said Feb. 12.

But American scientists, while agreeing that Facebook use could influence behavior and brain function, said research into those effects is only beginning.

"Social networking sites are very powerful," said Dr. Gary Small, a neuroscientist at UCLA and author of the book iBrain: Surviving the Technological Alteration of the Modern Mind. "They can really help people in many ways, but they also do have risks."

Small said the idea of Web sites affecting brain function is not far-fetched: A study he performed found increased brain activity after a computer-naive person was taught to use Google.

BJ Fogg of Stanford University, who has taught classes on "the psychology of Facebook," wasn't surprised to hear alarm spread in certain circles about the site, but he doubted it would have much of an impact.

"Even if there were evidence Facebook was somehow changing the brain in a bad way," Fogg said, "I don't think people would stop using social networking."