An autosuggestion is an instance of suggesting a thought to oneself.

The cast of Autosuggestion - 2003 includes: Jacqueline Phelps as She Oliver Warsitz as He

The cast of Autosuggestion - 2008 includes: Leoni Katsarou Melani Perperidou

Hermann Schmidhauser has written:

'Lebe besser mit Autosuggestion' -- subject(s): Autogenic training

If another person tells you there is a ghost and you WANT to see a ghost, you will see one.

It is called autosuggestion. You are told there is a ghost so you believe you will see one.