Re: why do people become silly when they are nervous?

Dear Toko,

The nervous system can be divided in different parts such as the central 
(brain & spinal chord) and peripherical (autonomic and skeletal) systems. 
The autonomic system directly influence some internal organs. It can be 
divided in two general systems that have opposite effects on organs : 
sympathetic and parasympatetic. The sympathetic system is active when an 
individual faces stressfull events. In such circumstances, the heart rate 
is increased, the eyes pupils are wide open, energy is sended to muscles 
and so on. The parasympathetic system is active when the individual is 
more relaxed : digestive functions are increased, heart rate slow down and 
the pupils contract. Although not all reactions fit this scheme, I think 
this is a useful way of looking at the autonomic nervous system.
It is interesting to notice that this is precisely in the latter state 
(when the parasympathetic system is activated) that a person can 
concentrate himself into an intellectual task, not in a stressful 
situation. Nonetheless, if you (or an animal) see a wild animal in a 
forest, it is the sympathetic system that will be activated and you will 
probably not be in the mood for solving mathematical problems. On the 
other hand, your body will be ready to run and react rapidly to a possible 
aggression. There is a kind of equilibrium (homeostasis) between the two 
systems that varies according to situations that the individual 
experienced. 

I hope this helps !
Eric