Final answer:
Smiling when laughing is a universal human behavior, rooted in biology, psychology, and social interaction. Studies have uncovered that the expression of emotions, like happiness, has distinct facial expressions ingrained in our biological and societal constructs, contributing to cultural bonding.
Step-by-step explanation:
People smile when they laugh as this behavior is deeply rooted in our biology and psychology. The behavioral interaction of laughter and smiling, main components of human emotional expression, is virtually universal across cultures, demonstrating its basic and fundamental nature in human communication.
A study by Soussignan demonstrated the role of Duchenne smiles, or genuine smiles, in emotional experiences and autonomic reactivity. This means people often smile when they laugh due to naturally wired responses in our bodies.
Furthermore, research conducted by Paul Ekman supports this understanding. Ekman identified a set of universal emotions, one of which is happiness, and each of these is associated with distinct facial expressions such as smiling when we laugh, suggesting this to be a universally ingrained pattern.
Murdock's studies also show that humor is a universal aspect of human societies, and the shared experience of laughter and smiles contribute to cultural bonding, suggesting that the act of smiling and laughter serve not just an emotional purpose but a societal and communicative one as well.
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