A scientific experiment has found that two mediums were unable to demonstrate that they had special psychic powers.
The test by researchers at Goldsmiths, University of London, tried to establish whether mediums could use psychic abilities to identify something about five unseen volunteers.
The results, carried out under test conditions, did not show evidence of any unexplained powers of insight.
But medium Patricia Putt said this experiment "doesn't prove a thing".
This Halloween challenge was an attempt to investigate whether professional mediums could demonstrate their psychic powers in a controlled setting - by inviting them to deduce something about people they had never met and could not see or hear.
The experiment, designed by Chris French, head of the Anomalistic Psychology Research Unit at Goldsmiths, asked two professional mediums to write something about five individuals who were concealed behind a screen.
These five volunteers were then asked to try to identify themselves from these psychic readings - with a success rate of only one in five.
This was a result that was "entirely consistent with the operation of chance alone", said Professor French.
But one of the mediums, Patricia Putt, rejected the suggestion that this showed any absence of psychic powers - saying that she needed to work face-to-face with people or to hear their voice, so that a connection could be established.
"Psychic energy" was not likely to work in the setting created for the experiment, she said, and her success rate was usually very high.
Ms Putt said the experiment was designed to confirm the researchers' preconceptions - rather than examine the nature of her psychic ability.
"Scientists are very closed-minded," she said.
She said there were fraudsters operating as psychic mediums - but that it was wrong for scientists to think that such mediums "were all the same".
But Michael Marshall of the Merseyside Skeptics Society, who helped to organise the test, said it showed that claims to have special abilities "aren't based in reality".