Expressive Psi – Also known as Psychokinesis (PK) or Mind-Over-Matter. It is the ability of the mind to influence objects or processes without the use of known physical forces. Parapsychology breaks psychokinesis into two forms – micro and macro. Micro-PK are affects that happen at a microscopic or subatomic level requiring equipment to measure the results. Macro-PK is observed by the naked eye and involves metal bending, materialization or dematerialization, or other major mind-over-matter interactions. Poltergeists are believed to be a form of Macro-PK caused by the living, not ‘ghosts.’