A procedure for the measurement of infant skin conductance and its initial validation using clap induced startle

Studies examining psychophysiologic markers of infant emotional development abound. However few studies have used skin conductance (SC), though it measure's sympathetic activity, and none have measured SC on infants sitting up and actively engaged with another person, a significant challenge given the measures sensitivity to movement artifact. In this pilot/feasibility study, we present a procedure for measuring infant SC during active engagement with another person who executes a series of startling claps to elicit an SC response. We measured SC on the plantar surface of the foot of seventeen 5-month-old infants. We found unconditioned SC responses that were related to the intensity of physical startle reactions for each clap trial. We also found anticipatory, conditioned SC responses that occurred within 5 s before each clap that occurred when the researcher raised his clasped hands. These conditioned SC responses grew linearly in intensity over trials. We conclude that SC may be a useful addition to the infant researcher's armamentarium and may indeed be used to measure physiologic reactivity in infants even when actively engaged with another person. Addition of SC measurement to research on infant emotion and emotional communication is likely to advance our understanding of the psychophysiologic foundations of infant emotional development.