Peepers,

thank you for your information and expertise ! 

In my case with my dog, when she considers someone a threath. 

She has to make up her own mind. i can pretty much make her stop barking but the growling and the constant distrust of the person continues and it will not stop untill this Person leaves

she only trusts my family and a few people she know from puppyhood but that's it 

no training just genetics i believe ...

i believe all CO's should be very distrustfull towards all strange people and you should notice this from early on in puppyhood