A relationship between Eysenck's P scale and change in muscle action potentials with attention to perceptual tasks.

An experiment is described in which an index of change in muscle tension produced by perceptual discrimination tasks, and scores on Eysenck's PEN scales, were measured on 39 university students. It was hypothesized that if P is an index of psychoticism, as has been claimed (Eysenck & Eysenck, 1968) then an index of one central feature of so called 'psychotics', namely attention difficulty while decision making, should correlate positively with P. P was found to correlate significantly with a measure of increase of EMG on the perceptual discrimination tasks (r = 0-54, P less than 0-001). Correlations of this index with N and E were zero. The results are considered to be particularly significant, since scores on P, E and N gave almost zero intercorrelations in the sample tested, and L scores were exceedingly low. Further evidence is provided which suggests that both P and muscle tension increase are directly related to the degree of endorsement of paranoid ideas.