Why are laughing and crying so similar?

[Fishcat]

And one so often leads to another...are these apparently opposite emotions the same?

 

[yourinnervoice]

it's all spontaneous response.

 

[carey_ball]

I'd rather have a free bottle in front of me than a pre-frontal lobotomy.

I think humans are the only animal species that can do either. Same with blushing.

 

[Mark]

Opposite but equal emotional responses at the other end of the spectrum from each other, like love and hate.