This study presents, for the first time, (a) the analysis of the modern literature on the reciprocal impact of emotional arousal and interactional synchrony that creates the synergy of this tandem increasing group productivity; (b) the empirical results of 10 online experiments with 41 dyads. These online experiments in different languages found a 54% increase in group productivity (41% above chance, the p-value < 0.001). The research question of the study is to understand why individuals look for synchrony. A highlight of the article is the hypothesis about the emergence of coherence of emotional arousal and interactional synchrony, the outcome of which enhances group performance. This Model of Coherent Intelligence is supported by laws of Physics and arguments of Social Sciences which are strictly based on experimental data in the modern literature. The study proposes directions for improving e-learning, using Coherent Intelligence. .