Electrodermal arousal between participants in a conversation: nonlinear dynamics and linkage effects.

Physiological linkages between two people in conversation were investigated from a nonlinear dynamical systems theory perspective. Thirty-seven pairs of college students engaged in a 20-minute discussion while connected to electrodes that measured their electrodermal response (ED). Greater incidents of linkage were detected through the nonlinear regression analysis compared to linear models. The nonlinear models were exponential structures that determined positive Lyapunov exponents (and thus the presence of chaos) for 73 out of 74 participants. Results support the use of nonlinear models for interpersonal linkage effects of this type. For each participant, Social Sensitivity from the Social Skills Inventory was correlated with the nonlinear model R(2) coefficient, but not with the size of the Lyapunov exponent. The latter results supported the conclusion that empathy acted as a moderator of the nonlinear process that underlies changes in ED levels over time.