Technically spanking is not really discipline, it's punishment. Discipline is "to teach". Spanking is only "teaching" to be afraid and distrustful of adults.
Nonsense. When a puppy is smacked with a rolled-up newspaper for piddling on the floor, that's called "training." It's not punishment, it's teaching. Young animals of all species can be taught pretty much the same way.
It's not good training. Having raised both kids and dogs, I can affirm that positive reinforcement is a better training tool than punishment. Even and actually, especially when it comes to house training puppies.
I've known people who raised or 'raised' puppies and felt themselves to be quite expert in the practice, utilizing all sorts of harsh punishment, including the newspaper on the nose. They were shocked when they noticed my pretty well behaved dogs, raised by me and my husband (and kids) without any physical punishment, although I will cop to an occasional shout which really only confused the dogs. They knew I was angry but were not able to correlate my anger with their misbehavior.
Of course, dogs are not the same as children, although the 'training' process for young children and puppies is much more similar than I realized until I raised puppies after my children were school age and out of that 'puppy' stage themselves.
Certainly, some breeds of dogs present different challenges as certain behaviors (herding, pointing birds, retrieving, etc.) have been bred into them for generations and within breeds, dogs are as individual as humans are. Likewise, some children are very easy to raise and others are more challenging. It is pretty easy for a parent who has an easy child to believe that their child is well behaved and likeable because the parents are so skilled at parenting. That gets blown all to hell when another child who is not so easy and indeed, quite challenging comes along. I may be speaking from personal experience and such scenarios may bear an uncanny resemblance to my own experiences as a parent and as a dog owner.
In child rearing and in puppy rearing, it is important to be observant about what the individual child or animal is like, what motivates each, what their preferences are, what their limitations and strengths are. One should always strive to establish a routine and practices which best ensure opportunities for success as well as opportunities for growth. Some examples of recognizing individual preferences and limitations: I have children who are very extroverted and social. From a very early age, removing them from any social interaction, whether it was playing on the playground, or with siblings, or actual grounding when they were older was absolutely the worst punishment I could mete out. It was pretty hard on the rest of the family who had to endure the sentence as well. I also have children who are fairly introverted: ground them and they were happy as clams sitting on their beds, reading a good book. A more effective punishment was to hand out extra chores of the kind they did not care for, or to insist that they stay in the kitchen and help prepare a meal and clean up instead of retreating to their bedrooms and books. And so on. Some dogs are very food driven and will do anything for the tiniest bit of treat. Others are much more motivated by play. If you want to get the most out of a training session, you need to know what motivates your dog. Or kid.
As a child I was spanked, although I don't really remember it much. I do remember by the time I was in upper elementary school and a younger sibling was going to be spanked, that I thought it was very, very wrong to hit my sibling, although frankly they were being punished for an offense against me. I could understand and comprehend a quick swat to a bottom of a small child to immediately grab attention and indicate something was wrong. Note I am saying: I understood it, not that I thought it was the best thing in the world to do. My father was firmly convinced that respect and obedience were founded in fear. What motivated me was fear of losing my father's approval, not fear of being hit. That said, I know my father was punished quite severely--my grandfather beat him on occasion. I also know my father was probably one of those more 'challenging' kinds of kids: very much a thrill seeking, authority challenging, adventurous, mischievous child who would have been a challenge even to a parent who wasn't as overwhelmed with a chronically ill spouse, trying to keep his family from starving to death (literally. It was the depression.)as was my grandfather.
On rare occasions, I admit that I did spank my children, a couple of times. Once was when one of them dashed into a parking lot, as a pure reflex action on my part. I wish I had not spanked him--a couple of swats on his bottom-- and wished it at the time. I wish it even more strongly now. But I did do it. It is not easy to break patterns you were raised with. My kids have grown up to be kind, loving, competent adults who are not prone to violence or low self esteem. It is possible to make mistakes as a parent and have the kids still survive and be good kids.
What I see now with (some) parents is the parents refusing to actually discipline their children. I don't mean spanking or time outs, even. I mean, plenty of parents see no reason to stop little Hunter from kicking the back of someone's seat or running around a restaurant or smashing their ice cream cone where ever little Hunter chooses. They also see no reason to curtail whatever errands or activities the adult wishes to engage in simply because Hunter needs a nap or a meal or to be home because Hunter's nose is running lots of green snot and Hunter is clearly past his or her possible endurance for a marathon shopping event at the mall or TGIFridays or whatever. The parental attitude seems to be (and has actually been stated to me by younger parents of my acquaintance): " why should I be inconvenienced because little Hunter won't behave?" Of course that begs the question: Why should the world be inconvenienced because you cannot be bothered to actually raise your own child? Or more seriously: How will little Hunter learn to get along in the world if s/he has no idea of limits and expectations and that kicking the back of someone's seat is almost certain to make them dislike you?