The dogs haven't changed a bit they still get trained or not whatever method you use.
Its very easy to confuse yourself by reading too much, best way of learning about how your dog ticks is to watch it and its interactions both with you and with others and think about what you see. There's an awful lot of balderdash out there which just serves to confuse rather than educate. Having said that I enjoyed the John Bradshaw book but I find I can learn stuff from old books too, take what you need from each book none of them will tell you what your dog is thinking any given moment!
I was getting the dogs' supper this evening, trod on the pup and set my dickey hip on fire trying to avoid her. I swore very loudly and two of the dogs wouldn't eat afterwards. No dog psychology books will cover that kind of scenario!