Reality discrimination, reality monitoring and disposition towards hallucination.

This investigation tested the hypotheses that individuals disposed towards hallucination are deficient in the meta-cognitive skills of reality discrimination and reality monitoring, and that there is a strong correlation between the measures of these skills. Normal subjects scoring high or low on a scale measuring predisposition towards hallucination were tested on an auditory signal detection task. High scorers on the scale were found to differ from low scorers on a measure of perceptual bias but not on a measure of sensitivity. The same groups of subjects were tested on a reality monitoring measure in which they were required to monitor two different types of word: words they were required to listen to, and words they were required to listen to on some trials and imagine on others. On a surprise frequency test it was found that high scorers did not differ from low scorers on their ability to accurately count the memories of words they had heard. It was also found that both high scorers and low scorers overestimated the number of times they had heard words when they had also been required to imagine these words on tests; however, high scorers made this error to a significantly greater extent. A strong correlation was found between reality discrimination and reality monitoring measures for high scorers, but no correlation was found for low scorers.