 Have nearly four million Americans been abducted by aliens? A poll in 1994 claimed that one in forty of the US population are the victims of abduction by an alien race called  The Greys . In the last ten years, thousands of people, from around the world, have come forward to describe an experience that is astonishing in its detail and consistency.  Close Encounters  is an exploration of the paranormal alien abduction belief by psychologist Dr. Susan Blackmore and was made for the BBC s science flagship series Horizon. Sue Blackmore has spent over 20 years investigating the paranormal but, in all that time, has found nothing that really convinced her that anything paranormal was going on. Her search takes her from alien abductees to UFO researchers, then to a leading psychiatrist who believes the abductees, on to hypnotists, psychologists and victims of supernatural apparitions. Finally, Susan is shut in a sound-proofed chamber where a neuro-biologist induces a terrifying encounter by creating an hallucination using electromagnetic waves. This mimics the natural misfiring of the brain and convinces her that, rather than looking to the skies, we should look inside ourselves at the still poorly understood workings of the brain and memory for an explanation.