Answer to Question 1
Answer: Researchers refined Cattells work on 16 factors into 5 personality factors. They are labeled big because they are quite broad. Each of the Big Five factors describes personality at a high level of abstraction, and these are further broken down into smaller lower-level traits. When personality descriptions such as the California Q-sort or the Myers-Briggs Type Indicator are analyzed statistically they often derive five clusters of descriptions. If there are universally five, or so, types or sets of traits, then there is likelihood that they are biological or genetic in nature to a significant degree. Currently a five-factor taxonomy is the most widely researched.
Answer to Question 2
Answer: Researchers use one approach or a combination of approaches, such as the lexical approach, the theoretical approach and/or the measurement approach to identify words used in a given group or society to describe personality. The theoretical approach starts with theory and derives words and concepts implied by the theory. Because Jung theorized about personalities dominated by either thinking or feeling, words that would describe these activities would be included in a Jungian personality approach. A lexical approach simply looks at a given language and pulls out words used to describe personality assuming that they are based on the observations of that culture. A more systematic approach is the measurement approach, which often uses statistics to analyze how descriptions cluster together.
