Effects of phase-of-respiration on GSR detection

Previous studies of visual and auditory signal detection (Flexman & Demaree, 1972; Flexman, 1974; Flexman, Demaree & Simpson, 1974) have found that signals occurring during exhalation are detected with greater sensitivity than are signals occuring during inhalation. The purpose of the present study was to make use of a use of a signal detection paradigm (Green & Swets, 1966) in extending these phase-of-respiration findings to internal event detection, specifically, to the detection of spontaneous galvanic skin responses (GSRs). A secondary purpose of the study was to re-examine Stern's (1972) finding that high magnitude GSRs were better detected than were low magnitude GSRs. It was found that the phase of respiration during which the GRS reached its peak significantly influenced GSR detection, but that unlike studies of external signal detection, detection was greater for GSRs peaking during the inhalation than for GSRs peaking during exhalation. Some possible artifactual sources of this finding are discussed. No significant effect of GSR magnitude on GSR detection was observed although differences were in the expected direction.