“…Research into how activity on these peripheral indices relates to behaviours such as attention or emotion reactivity has a long history ( Broadhurst, 1957 , Yerkes and Dodson, 1908 ). For example, better learning has been associated with increased event-related heart rate ( Linnemeyer & Porges, 1986 ) and electrodermal activity (EDA) changes ( Brown, 1937 ). However, the majority of previous psychophysiological research examines relations between a single measure of peripheral autonomic activity and a behavioral measure.…”