Typically, people from small families had parents who are highly educated & less religious. Such parents are also very liberal, supporting reproductive freedom & family planning. Because of their high level of education, they are cognizant of the fact that children need individualized parental time, love, & attention & that the more children in the household, the lower quality of parenting. Their high educational level opens them to exposing their children to cultural & intellectual activities which broadens the latter's perspective. Children from small families are widely exposed to cultural & intellectual activities which makes them advanced academically as well as socially, being exposed to a wide variety of people.
Conversely, people from large families had less educated & more religious parents. Such parents are also very traditional. They don't believe in reproductive freedom nor family planning, believe that both are somehow unnatural. Their lower educational level dictates that children are preordained by God. As a result of having a large number of children, poverty is commonplace which means there is little or no money for necessities, even that. Another aftereffect of poverty is feeling powerless & that the world is somehow against them. This fosters a us vs them philosophy. The average person from a large family is insular, never trusting outsiders & is content only associating w/their immediate family members. Since there is little money in the house, there is no exposure to intellectual nor cultural activities which would broaden a person's perspective on life. Because those in large families associate primarily w/each other, they oftentimes have very parochial outlooks on life.