In middle school I had a science teacher who would tell the class that, while we took tests, she could project herself above and behind the classroom and watch us to make sure we weren't cheating. Seriously. We always thought she was just giving us an excuse to close her eyes and nod off during the test. That, or there were some loose wires in her head.
As it turns out, the latter theory might be pretty close to the truth. In recent studies, neuroscientists have been able to re-create an out-of-body sensation by stimulating specific centers of the brain electrically. When mild electric currents were placed on certain areas of their brains, epilepsy patients claimed not only to find themselves suddenly floating above their bodies, but also at times to feel a malevolent, shadowy presence right behind them, mimicking their moves. Scientists think such electrostimulus can copy the way the brain misinterprets signals to the point where it doesn't quite know where the body is.
Although this could put the kibosh on any theories of ghosts or shadow people as a mere case of pareidolia, most supernatural stalwarts won't be convinced. Ghost hunting—an attempt to scientifically explain the unexplainable—has been around for more than a century and has become prominent in books, television programs and movies. The paranormal is deeply entrenched in our society, and there have been too many seemingly unexplained occurrences to give up on it completely.
So if you see a ghost, who you gonna call? A bunch of neuroscientists to help fix your head? Or Ernie Hudson to bring over his proton pack? —Dan Smith