Bilateral electrodermal asymmetry: past hopes and future prospects

In the present paper, I have reviewed data and evidence concerning bilateral electrodermal (EDA) recordings and hemispheric asymmetry. Nine papers published between 1982 and 1986 are evaluated together with the 51 papers reviewed in the prior Hugdahl (1984) paper. The overall impression of the data is skepticism concerning what bilateral differences imply. This does, however, not imply that EDA is a less relevant index of hemispheric asymmetry compared to other psychophysiological measures. The important aspect of psychophysiological laterality research is not the use of different dependent measures, but the design and manipulation of the independent variables. Thus, increased responding to a verbal stimulus initially projected only to the left as compared to the right hemisphere may be as instructive concerning conclusions about asymmetry as bilateral differences to a stimulus presented to both hemispheres simultaneously.