In the movie “Rain Man,” Dustin Hoffman played Raymond Babbitt, a man severely limited by autism who nonetheless showed a remarkable ability to memorize every name in the phone book, among other mental gymnastics. One of the people who inspired the film was Kim Peek, pictured here. Savant syndrome mostly appears in people with developmental disabilities (though some people develop it after severe head trauma). Most savants have trouble carrying out the simplest everyday tasks and social interactions, but display brilliance in one area. For instance, they may be exceptionally gifted musically or artistically at an early age or endowed with prodigious brain capacity that allows them to instantly compute complicated mathematical calculations in their heads.