To all the extroverts here matching introvert traits to themselves: This only applies on Keirsley theory.
Cognitive functions theory does not see introversion and extroversion as independent traits, but a part of your MBTI, showing if your first function is extroverted or introverted. Function theory states that your amount of social interaction is NOT dependent on whatever you're an E or I, these two only show what is your preferrence for social interaction. One prefers to keep in touch with plenty of acquintances, the other prefers to stay with a couple of best friends.
The cognitive theory sees introversion and extroversion as nothing more than that, no extra labels with adjectives pointing that "oh gee, that dude who didn't say anything all day is soooo totally an introvert" or "oh gee, that girl was dancing all night like a champ. What an extrovert. Only an extrovert could muster the energy to dance all night long".
For example, it all applies to all your letters, like how you can't say to a xxxJ that "lol why is your room such a mess, i thought you're always in order". You also can't presume that a sensor is incapable to come up with intuitive ideas, or that an intuitive is incapable to enjoy the here and now. You also can't presume that all scientists must be thinking types, or that all the artists and poets are feeling types. So why would you presume any assumptions on Introversion and Extroversion alone, stripped off from the rest of the letters?
As OMG WTF BRO already stated, let me explain in terms of math :tongue:
The amount of social interaction =/= The amount of people
Introvert =/= Quiet loner
Extrovert =/= Loud and obnoxious
Introvert = The attitude of your first function is Introverted
Extrovert = The attitude of your first function is Extroverted
Do you mean Keirsey's theory? Cognitive I/E and common conceptions of I/E need not be universes apart, even if they may not always be the same.
Just because someone does not relate to any of the 23 introverted traits doesn't make them loud and obnoxious, and relating to all 23 does not make a quiet loner.