I think the point was that children in a large family have learn a certain amount of aggressiveness in order to get their fair share of dessert, attention, etc.
It doesn’t matter how loving the family or how well enforced the discipline is. Both cake and parental attention are limited resources and, in large families, if you won’t fight (overtly or covertly) for your share, you’ll get cut out.
No ... sure there is competition for the parents’ attention but that doesn't include fowl language or being violent at THAT young age just because it is a “large” family. Look at the Duggers! Are they violent little foul mouthed kids?
I disagree that kids in large families must be primitive to survive and thrive. Typically kids in large families have better social skills BECAUSE they have had someone TEACH them how to be patient and share etc.. When that is NOT present, you will have a dog eat dog atmosphere.
It's up to the adults to mold their will to what is right and beneficial to each personality. Each personally will have its strengths and weaknesses. It is up to OBSERVENT parents to help them over come weaknesses and praise them for their strengths and just plain encouragement to be the BEST you can be.
Watch the Duggers sometime. They have their missteps but adults NOTICE and work with them. I just can't use a “LARGE” family as an excuse to be like little selfish animals.