Intro to the concept of instinctual stacking here.
What sets apart those who are social-first?
On the most basic level, they have a desire to be accepted into and approved of by a group. Being smiled at, welcomed, hugged, and/or even admired and respected by everyone within a circle of friends makes them feel happy and comfortable. They may seek this end result through various kinds of friendly, meek, cooperative, nice, sweet, considerate behavior, or through whatever type of behavior is approved of or considered "cool" by the group they desire to be accepted by. The average social-first person is, in other words, highly vulnerable to peer pressure; but whether or not they've donned tough exteriors, on the inside (and usually it does show on the outside as well) they are soft, sweet, tender, vulnerable, earnest, childlike, and eager to please.
Due to caring what everyone in the group thinks about them, the attention pattern of the social-first is diffused, taking in the vibes and the vocal, facial and body-language cues of everyone around them simultaneously. And just as diffused light is softer and gentler than a single point of light focused through a lens, similarly the energy of the social-first is easier for many to get along with or feel comfortable around than the intense energy of the sexual-first. Of course, if the social-first in question happens to be hyperactive or full of super bouncy energy, have strong opinions, or be very attached to certain habits or traits that are perceived as flaws by others, that may be difficult to handle for others who don't share that aspect of their nature or have any attraction to it; I don't mean to imply that social-first people don't have their own ways of being intense or difficult from time to time! Everyone has his or her own personality, and can adjust it to suit others only so far before snapping back into authentic individuality. But at least, with social-first people, there's more of an awareness and concern about the feelings of others, so they will often endeavor to be considerate as best they can given their nature, whereas sexual-first people tend to focus most on their own interests and desires (and those of the particular other people they care about most), and may sometimes be a bit inconsiderate toward those whom they've mentally ranked as less important to them.
The heightened awareness of others that social-first people have is related to such traits as sympathy and compassion; if you're very in-tune with the feelings of others, it's natural to feel that you can't be happy if someone else isn't. As a result, social-first people are the likeliest people to engage in altruistic work. Even if they don't engage in it themselves, they'll often find some way of supporting it, whether that be through giving in charity, voting for candidates who promise to help the downtrodden, purchasing from companies that try to do good or make a difference in the world, or some other means.
Some social-first people are content to lead simple lives with no greater ambition than to be accepted by a certain limited group of people who are important to them. Whether that be their family, friends, neighbors, schoolmates, and/or co-workers, these people have a smaller, narrower circle of concern. Others who are a bit more broad-minded may still be affected by a strong sense of pride and "clannishness" (or patriotism) that leads them to care a bit more about their fellow countrymen and their own nation than those from elsewhere in the world (or maybe those who share some other important trait with them, such as belonging to the same race, religion, gender, etc.). Still others, more broad-minded yet, see no differences that matter between human beings of any description, and long to see all humankind getting along joyfully together and treating each other well; and the most broad-minded of all bestow their boundless compassion upon every species of living being in existence. However limited or expanded the social-first person's circle of concern may be, there is a strong sense in them of yearning for everybody to be "one big happy family."