A Stanford social scientist who studies biases that creep into the thinking of people who don't realize they are prejudiced - and uses the information to help police avoid racial profiling - is among 21 winners of this year's lucrative MacArthur grants, to be announced Wednesday. Jennifer Eberhardt, 49, an associate professor of psychology, is the Bay Area's only winner of the $625,000 prize that rewards exceptional creativity and accomplishment, according to the John D.