Why do people see ghosts?

For Halloween, we explore ghost sightings - how to explain them, what research says and if there's an ethical imperative to acknowledge them.

The Difference Between Dark Matter, Dark Energy And Ghosts : 13.7: Cosmos And Culture : NPR

Why do so many kids 'see ghosts'? We asked some psychologists. - The Washington Post

Seeing Ghosts: A Brief Look at the Curious Business of Spirit Photography · SFMOMA

SEE THE PIC: Pennsylvania mom 'too scared to sleep' after seeing ghostly figure on security camera

The 5 Different Types of Ghosts (with pictures) - Louisville Tours

Can Kids See Ghosts?

Do Blind People See Ghosts? - All About Vision

Brian Cox says CERN's LHC would have found ghosts if they existed

I see dead people': why so many of us believe in ghosts

Ghost Hunting: Professional Tips

Why Are There So Many Female Ghosts? - Atlas Obscura

13 Terrifying Pieces of Evidence from Ghost Hunters: TAPS Returns, Ghost Hunters