[extropy-chat] extension of jolly good theory

[Acy James Stapp]

Spike wrote:
> Nowthen, here is what puzzles me.  I have been in situations
> where I was completely unable to supress laughter, most of
> us have.  This leads me to the following questions:  Do all
> humans and human societies have laughter?  Do all humans
> have *involuntary* laughter?  Is there anything analogous
> to that in other mammals?  If involuntary laughter universal
> in humans, how does that response get hardwired to our sense
> of humor?  Should I stick with rocket science?

Apparently baby rats laugh little ultrasonic laughs while 
playing.  Couldn't find the original reference, but Wikipedia
mentions it:

     http://en.wikipedia.org/wiki/Laughter
     "Laughter is not confined to humans. Chimpanzees show 
     laughter-like behavior in response to physical contact, 
     such as wrestling, chasing, or tickling, and rat pups 
     emit short, high frequency, ultrasonic vocalizations 
     during rough and tumble play, and when tickled. Rat 
     pups "laugh" far more than older rats."