Yawn Contagion and Empathy in Homo sapiens
Stacked histograms displaying the repartition of yawn response % per each latency category (Y axis) within each social bond category (X axis). Response latency categories: 0 = 0<tr≤1 min (black); 1 = 1<tr≤2 min (white); 2 = 2<tr≤3 min (grey). Social bond categories: 0 = strangers; 1 = acquaintances; 2 = friends; 3 = kin with r≥0.25 and life partners). Social bond has a significant effect on response latency in the best model (GLMM, AICc = 1116.694, n = 149).