In order to understand what a type has in common with the other three members of its quadra, you'll need to know some of the quirks of each kind of function. The nature of subjective functions is that they tend to be more... serious or refined, more focused on specific parts of the realm they deal with. They're limited in their view of reality because they have a scope defined by the individual, but they tend to have a more honest attitude in that they're more open to a varying quality of conclusions. Objective functions look directly at the world and thus have a more realistic starting place, but the broad scope tends to make them... optimistic. Perhaps as a way of dealing with a much broader array of information, objective functions seem to take things less seriously and focus on the good things found in their sphere.
The easiest way to explain this is probably with Ni and Ne. Ni is a subjective set of patterns and connections, disconnected from anything outside the person. Because Ni is subjective, it tends to regard a much higher spectrum of possibilities than Ne. Ni, depending on the individual, is more likely to pursue a single vision or single possibility rather than open up and explore other possibilities. This can be harmful in some cases, but because Ni is willing to go anywhere to find the absolute best possible explanation, Ni-types often pick up on much more complicated and realistic possibilities than Ne-types. Fe, by contrast, is concerned with connections, emotions, and values of others. Fe often takes a more friendly approach, trying to affect everybody else instead of making itself honest. Its ethics are more practical and realistic than Fi's, but its self-knowledge can be severely lacking.
What a quadra is is a sharing of this preference in all functions. While the types and temperaments can vary wildly, and communication may not be the best because of flipped preferences, but they are subjective and objective in the same place. Each quadra contains two very different sets of people, but often the only barrier between them is communication.
That said, here they are with my thoughts:
Alphas are the types that have Ti-Fe and Si-Ne. Socionics describes this as a very lighthearted and friendly quadra, which is... not inaccurate, but it's not entirely true. Ne is a very optimistic, lighthearted and talkative function and Fe is a very warm, outwardly emotional function. When a typical Alpha gains energy, it shows up as a bubbly warmth. Alphas tend to be the types that find each other and form close-knit friend families, though this isn't exclusive. They're common performers and actors. Their internal world is more rigid and thoughtful, sequential and logical. They like categories even if they lack discipline to organize and enjoy having a large set of boxes in their heads to help them sort alike and unalike things.
-FeSi have the strongest articulation of the Alphas in lead Fe. They like getting out and influencing people, and at their best have a strong inclination to make sure that everyone is happy and to express themselves emotionally. Si gives them a very linear and categorical thought process, so they tend to spread Fe influence in small, individual ways according to a set of static values they apply to each situation. They like doing things where they can build connections with people. A lot of Fe-leads are into combat, martial arts, and building/engineer work, but I can't for the life of me figure out why. Maybe it's the integration of polar Ti that pushes them to be more thorough and refine their Fe get-stuff-done attitude.
-SiFe are similar with some key differences. Their Si map of the world is bigger and more detailed, their ethical strength is a little more subdued, and they're perception leads. A lot of these types are actors, and they're usually characterized by an easy-going warmth. They tend to like to do things for people, and the leading Si aids them in remembering and categorizing how to best take care of or interact with individuals. Look for friendly homebodies or acclaimed handsome actors who think of themselves as friendly homebodies.
-NeTi are... fascinated. That's a good way to put it. Enthusiastic, friendly when they have to be, and keen on learning and talking about interesting things. They don't tend to have a set list of jobs they're interested in, but a pile of skills and experiences that lend to a unique collage of stuff they like to do. Sort of Renaissance folks but less focused. Some are artists, some are singers, some are actors, some scientists, some inventors, and most have dabbled in multiple of these things and then some.
-TiNe are similar to NeTi but are a little easier to predict. They're very philosophical in their approach to things, be it science, math, art, music, film, writing, and so forth. Contrary to MBTI tradition, TiNe aren't that great in hard sciences like chemistry or applied physics. They are quite logical and detached like a good scientist, but they like ideas more than facts. Facts aren't plastic enough. If you want to find a TiNe, look for awkward, outsider-y actors, satirists, and basically anything an NeTi would do except they're only doing one or two things and they're probably pounding it into dust by overthinking it.
Next part, I'll discuss some of the inclinations of Betas.
-FeSi have the strongest articulation of the Alphas in lead Fe. They like getting out and influencing people, and at their best have a strong inclination to make sure that everyone is happy and to express themselves emotionally. Si gives them a very linear and categorical thought process, so they tend to spread Fe influence in small, individual ways according to a set of static values they apply to each situation. They like doing things where they can build connections with people. A lot of Fe-leads are into combat, martial arts, and building/engineer work, but I can't for the life of me figure out why. Maybe it's the integration of polar Ti that pushes them to be more thorough and refine their Fe get-stuff-done attitude.
-SiFe are similar with some key differences. Their Si map of the world is bigger and more detailed, their ethical strength is a little more subdued, and they're perception leads. A lot of these types are actors, and they're usually characterized by an easy-going warmth. They tend to like to do things for people, and the leading Si aids them in remembering and categorizing how to best take care of or interact with individuals. Look for friendly homebodies or acclaimed handsome actors who think of themselves as friendly homebodies.
-NeTi are... fascinated. That's a good way to put it. Enthusiastic, friendly when they have to be, and keen on learning and talking about interesting things. They don't tend to have a set list of jobs they're interested in, but a pile of skills and experiences that lend to a unique collage of stuff they like to do. Sort of Renaissance folks but less focused. Some are artists, some are singers, some are actors, some scientists, some inventors, and most have dabbled in multiple of these things and then some.
-TiNe are similar to NeTi but are a little easier to predict. They're very philosophical in their approach to things, be it science, math, art, music, film, writing, and so forth. Contrary to MBTI tradition, TiNe aren't that great in hard sciences like chemistry or applied physics. They are quite logical and detached like a good scientist, but they like ideas more than facts. Facts aren't plastic enough. If you want to find a TiNe, look for awkward, outsider-y actors, satirists, and basically anything an NeTi would do except they're only doing one or two things and they're probably pounding it into dust by overthinking it.
Next part, I'll discuss some of the inclinations of Betas.