I remember reading in a psychology text book in High School about "trait" based approaches to personality theories and laughing out loud (sarcastically).
Now I know why I distrust MBTI (and FFM even more).
It has to do with this hypothesis:
The lexical hypothesis posits that most of the socially relevant and salient personality characteristics have become encoded in the natural language (e.g., Allport, 1937). Thus, the personality vocabulary contained in the dictionaries of a natural language provides an extensive, yet finite, set of attributes that the people speaking that language have found important and useful in their daily interactions (Goldberg, 1981).
quoted from this paper.
Does anyone know how much direct testing of that hypothesis has been done? I find the fact that we even consider it, let alone, use it as a basis for our main approaches at deciphering personality an affront to common sense.
I know they've done some cross-cultural studies for Big-Five to try and nuetralize for culture, but to validate a good scientific (as apposed to an industrial or business) hypothesis, one needs to neutralize for almost everything else. How are you ever going to do that? The most salient parts of personality being encoded in natural language? AYKM?
If anything, they should record physiological responses to various forms of stimuli when trying to accomplish various tasks and do factor analysis on the results of that. That may tell us for sure, if there are indeed "types" of people. After we determine the types from physiological responses, perhaps we can start testing how particular types use words.
Almost none of my thoughts or feelings are naturally encoded in words. The words I choose are usually just idioms I stole from other people. Generally, I make language my bitch (another idiom I stole). I use it to attempt to convey whatever message I am trying to convey (success varies).
I am also not at all surprised that there are 5 factors. Analyze the human lexicon for the description of any pervasive concept and see if you don't come up with 5 factors.
I think the Big-Five gives is more a study of the human lexicon for describing personality that a study of human personality.