EEG alpha-hypnotizability correlations are not simple covariates of subject self-selection.

An earlier study (Dumas, 1977) summarized EEG alpha-hypnotizability studies and concluded that: (1) 'Correlations between alpha indices and hypnotizability are found only in studies using non-naive volunteers as subjects.' (2) 'Correlations are not found in studies using invited subjects.' Contrary to these conclusions the present paper demonstrates an inconsistent mix of significant and non-significant correlations between alpha density and hypnotizability in studies using drafted and volunteer subjects. It appears that alpha-hypnotizability correlations are not simple covariates of subject self-selection. Assumptions about alpha production and relaxation are also questioned.