Physical depiction of emotions

Laughter, as a muscular response, seems to depict itself the same way in every culture.  How did man first equate positive feelings with chuckling, positioning jaws or curvature of mouth? Normally pleasure/happiness triggers smiling, even babies show intriguing behaviour towards positive conditions like comfort. A baby cant analyze and reply accordingly by prior experience so how does it exactly assign the action to stimulus? Is it copying the parents  handling  baby care by simultaneously matching gestures to actions? May be, but that also points out a child can be brought up with mismatched values and inappropriate responses. Fear or anger can be confronted calmly. Odd combinations may be created too, like shutting one eye twitching the other and clenching teeth when feeling curious. As straining as it seems, laughing or crying are no less of efforts for facial muscles. Take crying for instance, what an unusual case tearing is. Yawning?

Physical *expression* of emotions. Much of it is instinctive, though there's certainly cultural influence. There's studies on the matter which you ought to elucidate yourself with rather than spew poorly thought out bullshit. A lot of animals show fear, anger and even yawning. Good luck "bringing them up with inappropriate responses".