There seem to be a range of answers to why people sometimes defecate/urinate when they’re afraid.
http://ask.metafilter.com/102281/Question-that-stumped-my-anatomy-professor-wife
has such a range of answers.
I don’t understand sympathetic or parasympathetic systems so if someone could explain it in laymans terms please.

I’m not convinced with lightening the body for flight…doesn’t make sense to me. mainly cos it surely doesn’t weigh all that much anyway.
I do like the subconscious thingy..that we subconsciously/consciously poo when we want to or can (generally)
what say you all?

wetting oneself is an infant response. the smell of infant urine is supposed to convince the ‘assailant’ that the child is not dangerous.

I realise that doesn’t address the OP but thought it was somewhere to start

Riff-in-Thyme said:

wetting oneself is an infant response. the smell of infant urine is supposed to convince the ‘assailant’ that the child is not dangerous.

But lamb in more tender than mutton…

purple said:

I’m not convinced with lightening the body for flight…doesn’t make sense to me. mainly cos it surely doesn’t weigh all that much anyway.

I would say that it is less about lightening the body for flight and more to do with freeing up the muscles in that area to allow better use.

Riff-in-Thyme said:

purple said:

I’m not convinced with lightening the body for flight…doesn’t make sense to me. mainly cos it surely doesn’t weigh all that much anyway.

I would say that it is less about lightening the body for flight and more to do with freeing up the muscles in that area to allow better use.

The brown note. Did the mythbusters bust that myth or not?

roughbarked said:

Riff-in-Thyme said:

purple said:

I’m not convinced with lightening the body for flight…doesn’t make sense to me. mainly cos it surely doesn’t weigh all that much anyway.

I would say that it is less about lightening the body for flight and more to do with freeing up the muscles in that area to allow better use.

The brown note. Did the mythbusters bust that myth or not?

They were not able to make anyone lose control of their bowels. So they called it busted.

Pardon me…I’m trying to eat my brekky :/

Riff-in-Thyme said:

purple said:

I’m not convinced with lightening the body for flight…doesn’t make sense to me. mainly cos it surely doesn’t weigh all that much anyway.

I would say that it is less about lightening the body for flight and more to do with freeing up the muscles in that area to allow better use.

I like this. I wonder if it happens if you were going to poo anyway (say in the next hour) or whether the bowel relaxes and it falls out. or something.

> defecating with fear

It’s definitely pre-human in origin. Gorillas do it more often than humans do.

mollwollfumble said:

> defecating with fear

It’s definitely pre-human in origin. Gorillas do it more often than humans do.

hmm. so it must fulfill some evolutionary purpose.

one of the replies on that page said if you stink of poo they won’t want to eat you.

mollwollfumble said:

> defecating with fear

It’s definitely pre-human in origin. Gorillas do it more often than humans do.

That is hardly exact. proof required. Defecating is perhaps more an offensive defensive action rather than of fear.. I’d suggest.

purple said:

one of the replies on that page said if you stink of poo they won’t want to eat you.

I reckon that hypothesis has some merit.

PM 2Ring said:

purple said:

one of the replies on that page said if you stink of poo they won’t want to eat you.

I reckon that hypothesis has some merit.

Unless you have a pack of wolves on your tail. Perhaps it serves a similar function to that of a thrown lizards tail.

I recall Wen saying something like its not actually poo as you might do in your ordinary ablutions it was more a liquid mess from only partially processed food.