Male chimpanzees signal their aggression when they display their big canines, in contrast with humans, who show small canines when they smile. Sergey Uryadnikov/shutterstock.com Dopamine may have given humans our social edge over other apes By Ann GibbonsJan. 22, 2018 , 3:10 PM Humans are the ultimate social animals, with the ability to bond with mates,Continue reading “Dopamine may have given humans our social edge over other apes”