“…High levels of tonic RSA reflect greater variability or greater differences in cardiac interbeat intervals between inhalation and exhalation (Katona & Jih, 1975). While in a state of relative quiescence, tonic RSA is thought to reflect a general psychophysiological flexibility or preparedness for adaptation should conditions in the physical or social environment require a different response (Beauchaine, 2001;Butler, Wilhelm, & Gross, 2006;Demaree, Robinson, Everhart, & Schmeichel, 2004;Friedman & Thayer, 1998;Porges, 1992). Conversely, low tonic RSA reflects rigidity or a diminished capacity for flexible responsivity (Ode, Hilmert, Zielke, & Robinson, 2010).…”