The first factor would be the types of crops they grew. Farmers in New England grew sustance crops, mostly to feed themselves. This led to small family owned farms, which would surround a group of houses which had an area of common ground in the middle of the town.
Now, the south tended to favor cash crops such as tobbacco and indigo and things of that nature. Tobbaco required large tracts of land and completely destroyed the soil in which it was grown. Houses were often further apart than they were in New England (remember the centralized town with teh farms on teh outside) and therefore people interacted less.
Another huge factor was the demographics of the regions. In New England, the population was almost equal between males and females, with the longest life expectancy in teh world. This means growing families and huge leaps in population. Since slavery was relatively uncommon in New England, families had children to work on their farm. Since the families lived in close contact with one another, things like school and religion were extremely important aspects of New England life.
In the South, men greatly outnumbered women, and disease was fairly common. The life expectancy was really low there, and families much smaller than their northern counterparts. Since the labor was provided by slaves, people had no real reason to have children, especially with teh life expectancy being so low. Since farms were so far apart, unlike northern towns, the south lacked schools and churches. This isn't to say that they didn't have them, they were fewer and farther between than they were in New England.
The gist of all of this is that due to low life expectancy, the reliance on cash crops, and the lack of education, the northa nd south were beginning to form different cultures. The North had these things, which created more tightly knit