Another Look at the Relationship of Electrodermal Activity to Electrode Contact Area

The present study was undertaken lo reexamine the hypothesis that the relationship between skin conductance and electrode size is monotonic and linear. Skin conductance activity was recorded from 48 right‐handed male subjects using 6 different sixes of electrode collars ranging in exposed surface area from .131 cm² to .786 cm². The dependent measures were skin conductance level (SCL); skin conductance response (SCR) amplitude to a series of 8 loud tones; latency, rise time, and recovery half‐time of the first tone elicited response; (he largest self‐generated SCR; and the number of nonspecific responses. The results indicated a significant linear relationship between contact area and SCL, stimulus and self‐generated SCR amplitude, and the number of nonspecific responses. Latency was not affected by electrode size although the other time‐based measures were. Differences in skin conductance activity were found among different palmar recording sites. The observed linear relationship between electrode size and electrodermal measures has implications for current models of electrodermal activity and for the comparison of results across studies in which different electrode contact areas are used.