Dr. Carmen Battaglia is a very well known in the dog world as on the board of the AKC and a writer and lecturer on puppy development and breeding better dogs.
Dr. Battaglia believes in careful breeding but it is most interesting to us that his research has shown that it is the ability to make use of the capacity you have that is more important that having a huge capacity in itself. We humans apparently use a very small segment of the brain power we are given and so it seems it is with dogs. To Dr. Battaglia it is giving puppy the stimulation to help him use the cleverness he is born with that is crucial.
Certainly we know that newborn human babies react to the early stimuli they are given. Babies who are well looked after but not cuddled, cooed to and touched do not perform as well in later life as babies who perhaps lacked the some aspects of physical care but were adored and fussed over as infants. Puppies respond very well to stimulation both by their dog mum and their human family right from birth.
A newborn puppy is only able to smell, suck and crawl on his belly. He knows when the temperature of his world is good for him. If he is cold he will snuggle up to his litter-mates or his mother. Temperature is very important to maintain his immature digestive system.