Nothing puts the horror into a horror film like an idyllic setting. That is how the 1956 science-fiction classic Invasion of the Body Snatchers begins. The inhabitants of the bucolic hamlet of Santa Mira, Calif., delight in their neighborly friendships and rarely have more than the most mundane concerns. But when town doctor Miles Bennell returns home after a short trip, he learns that one of his patients thinks her uncle is not really himself. The woman feels almost as if something evil is lurking behind his familiar face. Bennell is not too concerned. But then more and more patients become suspicious that a body double has replaced a spouse, relative or neighbor. Many of the doubles seem threatening, too. Bennell's sense of strangeness soon turns to awful certainty: alien invaders have chosen Santa Mira as the staging area for world domination. Under cover of night, they are taking over the bodies of their sleeping victims.
The insidious terror depicted in Invasion of the Body Snatchers exploits a primal human fear of total isolation: everyone we know becomes alien, leaving us utterly alone amid uncomprehending strangers who care nothing about our life or death. Moviegoers can escape this creepy world of doubles, but for people with Capgras syndrome, it is reality. Day in and day out, they firmly believe that certain people they know intimately have been replaced by robots, extraterrestrials or human doubles.