Controversies of Ganfeld studies of ESP and PK

ESP - 'Extrasensory perception', split into 3 sections, telepathy, clairvoyance and recognition.

Telepathy - the ability to communicate from on mind to the other

Clairvoyance - The ability to be a 'psychic detective', to find missing things

PK - Psychokinesis, the ability to move things with the mind

1) The Ganzfeld  procedure was developed by Honorton, he claimed input from the ordinary senses (e.g. sight, touch, etc) drowned out the psychic input. The ganzfeld state is when these sensors are blocked so participants are more perceptive to PSI.

2) Usually a 'receiver' is placed, alone in a room in a comfy chair, with half ping pong balls over their eyes and a red light shone on them. The 'receiver' then must wear headphones with white noise (static) playing. The will feel a state of sensory deprivation.

3) A 'sensor' in a (different room) observes a random target/object (e.g. zener cards) and tries to telepathically send the information of what they see to the 'receiver'. The 'receiver' then speak aloud what they see. A experimenter (blind to the objective of the experiment) records what the 'receiver' says, either by taking note or recording it on tape.

4) Each session lasts around 15 minutes. The 'receiver' then is the given a choice of images and asked to chose which they witnessed. There is a chance rate of 25%

Honorton (1982) found a success rate of 38% in a meta analysis - evidence for PSI

Hyman (1985) reanalyzed the data, found that there was no evidence due to the procedural flaws and statistical errors.

Honorton (1985) Reanalyzed again, agreed with the procedural flaws but argued there was not statistical errors - evidence for PSI

Hyman and Honorton (1986) Conducted a study together - created the Autoganzfeld 

Honorton (1990) used Autoganzfeld studies in a meta analysis of 11 studies, success rate of 34% - evidence for PSI

Milton and Wiseman (1999) used 30 studies, found no significance

Bem et al (2001) - Removed less well controlled studies and included more Autoganzfeld studies and found significance.

1) File draw effect -  The fact that many studies are filed away with non significant results. If these studies were published and included in all meta analysis there would be evidence for no ESP. Researchers are also biased and pick those studies which support their view. 

2) Sensory leakage - There are many ways information can be 'leaked' to the receiver during a ganzfeld study e.g. not all studies done in soundproof rooms, so if the 'sender' is shown a video, then the 'receiver' may overhear and figure out what's being 'sent'. Critics of the Ganzfeld and Autoganzfeld question whether sensors are truly blocked.

3) The receiver is required to to describe what they see, this can be wordy and there is room for subjective interperatation. Wooffitt (2007) analysed recordings and found skeptic experimenters didn't encourage elaborations of what was seen, other researchers did.

4) Carroll (2005) argues that PSI can only be argued to exist if all other factors are eliminated (e.g poor experiment design). Studies with positive results are JUST significant, possibility of a type 1 error? Replicability is usually hard to do.

Micro PK - A weak of PK, its not always noticeable e.g. effecting a coin toss or dice roll and is measured by statistical analysis.

Macro PK - Effecting larger objects that micro PK e.g. bending a spoon or levitating objects.

Uri Gellar - Apparently had macro PK abilities, he often 'bended' spoons and stopped/started clocks. His 'powers' were discovered by Targ and Puthoff. However, Uri Gellar was show to be a fraud when he failed to preform on the 'Tonight Show' on national American TV. He was presented with a wide range of spoons, watches and other things and asked to preform PK on them (he and his staff didn't know he would be asked to preform and his staff were not allowed to go near the props). Uri claimed he "didn't feel strong" that night so couldn't preform in front of millions. One of Uri's friends came out and admitted being a confederate during one of Uri's performances.

Nina Kulagina - Was apparently able to move objects and effect a frogs heart beat. She only ever preformed in her home or in her hotel room, due to the need to "concentrate her powers". Many of the things she moved can be done by anyone, e.g moving a compass by holding a magnet under a table or behind your back, other objects can be moved by telling threads or even hairs to.

Radin and Ferrari (1991) Did a meta analysis of 148 dice studies conducted between 1935 and 1987 (where participants tried to roll a 6) and found a high level of significance.

Steinhemp (2002) conducted another meta analysis, but with more studies and found no evidence for PSI.

The dice in these studies may have been weighed/fixed and the person rolling the dice may have effected to roll so a 6 would be rolled.