In addition to being the focus of corporate machinations, the Ouija board has also been invoked in many legal cases and has been featured in pop culture throughout the 20th century. But how does it work, psychologically speaking?
Research:

Embroidery History Sampler, Part 2
34:22

Embroidery History Sampler, Part 1
36:00

SYMHC Classics: Paul Cuffe
30:49