Variables in Photoplethysmography

摘要

In the present study an evaluation of several different measures of vaginal responding during erotic stimulation was undertaken. In addition, the experimental variable of probe size was examined to determine any effect, if any, upon the response. Results supported the use of measures of peak pulse amplitude and a measure that attempts to equate subjects on responsivity. Data revealed that the assessment of genital responding is facilitated by using larger samples of pulse waves and that probe size affected the amplitude of the pulse wave but did not interact with level of arousal. Analyses revealed that the use of change scores that attempt to control for baseline activity is a questionable practice. A discussion of the conceptual issues surrounding change scores is presented. That discussion reviews the serious reservations that are held concerning change scores. Psychophysiology has, in general, ignored these arguments and perhaps it is time to reexamine the issues.