Effects of 5 s exposures to a 50 mu T, 20 Hz magnetic field on skin conductance and ratings of affect and arousal

This study investigated the effect of a weak magnetic field (50 muT, 20 Hz sinusoidal, 5 a duration) on concurrent perceptions of visual stimuli. Subj ects were seated between Helmholtz coils and gave post-exposure ratings for the affective content and arousing nature of presented images. They were b lind as to the presence or absence of a simultaneously presented field. Ski n conductance and arousal ratings did not show significant differences betw een experimental and control conditions, but the affective content rating d id (P = 0.041), with the images viewed under field exposure being rated as having a more positive affect. Such measures might thus be useful as additi onal indicators of magnetic field detection. A post-hoc analysis of skin co nductance profiles showed that 48% of subjects exhibited a lowering of skin conductance during field exposure, 34% exhibited no apparent reaction, and 17% exhibited an increase. Overall ratings given by each of the groups app eared to relate to these physiological profiles. (C) 2001 Wiley-Liss, Inc.