
Early training and habituation can ruin a good temperament, and can improve a less good one, but some traits are unborn.
my breed the Norwegian Elkhound for example is a fre thinking independatn hunting breed,a dn these traits are very apparent from birth. Some of the less desrieable ones (from our point of view) can be tempered by training, but only tempered.
For example on walks my dogs will naturally range ahead, they have been trained to check back on me and their recalls ar not bad, but they are prone to throw a deaf un, especially if they see no valid reason for you calling them at that precise moment. On the other hand if a park vehicle is approaching or I shout bike, or there is a real urgency in my tone get their attention pretty quick.
One of mine came back to me at adolescence, and another of my breding didn't get proper training with his expereinced owner(obedience competitor) until he was 5 months, both of these are not as trustworthy off lead as their count3erparts that were brought up with their owners from pups knowing that very early recall trainign was needed, before they were confident enough to disobey.
Now my own dogs are very sociable with people and other dogs, but they have been brought up that way. Sadly one of my pups lives with a very neurotic older dog who had relied on her companion all her life and after it's death fell apart.
Now this pup started refusing to walk down her road to where the traffic was as the older dog was frightened, but woudl still walk where led as she didn't ahve the gumption to resist, but the pup did. I started taking both dogs out when she was five months as this had become a problem. I couldn't beleive how introverted they were. Over the next few weeks I had managed to get the older one to start interacting with people that stopped to speak and the younger one too, and had made headway with her digging ehr heels in and refusing to walk.
I couldn't understand why the owner didn't go to the shopping precinct where there are benches and let them watch the world go byu, but unfortunately teh owners are themselves very introverted, only go where it is quiet, are not kee to chat tio people etc, so sadly the headway I had made with the young bitch enjoying busy walks evaporated. When I had her here in the summer walks for her were a penance.
Now of course she may have been aless outgoing personality anyway, but had she been reared in my home she woudl have been as bomb proof as they are. Certainly she was a normal outgoing Elkie pup in the litter.