Physiological synchrony revealed by delayed coincidence count: Application to a cooperative complex environment

Synchrony at the physiological level is an objective measure that can be used to investigate cooperation between human agents. This physiological synchrony has been experimentally observed in different dyadic contexts through measures of the autonomous system such as cardiac measures. Various metrics were used to characterize synchrony between participants such as cross-correlation, weighted coherence or cross recurrence quantification analysis (CRQA) and with a wide variety of paradigms. We propose the delayed coincidence count as a new method for assessing cardiac synchrony. Delayed coincidence count has already been used to characterize synchrony in firing neurons populations. While being straightforward and computationally light, this method has already been formally proven to be statistically robust. A complex dynamic micro-world was designed with two difficulty levels and two cooperation conditions. Forty participants, i.e. 20 teams, voluntarily underwent the experiment. The delayed coincidence count method (with a coincidence threshold delta of 20 ms) revealed a significant synchrony (p < .01) during the cooperative and high difficulty condition only, while the other methods did not. The results are interpreted in terms of interaction intensity in accordance with recent literature.