Source Code, a sci-fi thriller released last week, is based on the premise that science will let people really get into each other’s heads. The eponymous technology, the trailer tells us, is a computer program that “enables you to cross over into another man’s identity.” What results is a scenario that’s part Matrix, part Groundhog Day: lugged into the Source Code program, Jake Gyllenhaal—er, Captain Colter Stevens—lives through the last eight minutes of another man’s consciousness, just before the man’s train was blown up in a terrorist attack, in an effort to identify the bomber. (Stevens’s body, like Neo’s, stays in one place while his mind is elsewhere.) When the first run-through fails to turn up a culprit, Stevens relives those eight minutes again and again, having a different experience—new conversations, new sensations—each time.
Could something like that ever happen? While much of the technology in Source Code will remain purely fiction, says University of Arizona neuroscientist and electrical engineer Charles Higgins, modern science may eventually let us take a peek at, and even play around with, someone else’s consciousness. Among the movie’s technological inventions, Higgins says, ”the idea of monitoring and influencing consciousness with a physical neural interface is the most plausible.”
These things always start small: First someone programs a computer to read minds, and next thing you know it’ll be 
