If stable and enduring traits guide our actions, can we devise valid and reliable tests of them? Several trait assessment techniques exist—some more valid than others. Some provide quick assessments of a single trait, such as extraversion, anxiety, or self-esteem. Personality inventories—longer questionnaires covering a wide range of feelings and behaviors—assess several traits at once.
The classic personality inventory is the Minnesota Multiphasic Personality Inventory (MMPI). Although the MMPI was originally developed to identify emotional disorders, it also assesses people’s personality traits. One of its creators, Starke Hathaway (1960), compared his effort with that of Alfred Binet (who, as you will see in Module 61, developed the first intelligence test by selecting items that identified children who would probably have trouble progressing normally in French schools). Like Binet’s items, the MMPI items were empirically derived: From a large pool of items, Hathaway and his colleagues selected those on which particular diagnostic groups differed. “Nothing in the newspaper interests me except the comics” may seem superficial, but it just so happened that depressed people were more likely to answer True. (Nevertheless, people have had fun spoofing the MMPI with their own mock items: “Weeping brings tears to my eyes,” “Frantic screams make me nervous,” and “I stay in the bathtub until I look like a raisin” [Frankel et al., 1983].) The researchers grouped the questions into 10 clinical scales, including scales that assess depressive tendencies, masculinity–femininity, and introversion–extraversion. Today’s MMPI-2 has additional scales that assess work attitudes, family problems, and anger.
Whereas most projective tests (such as the Rorschach) are scored subjectively, personality inventories are scored objectively. Objectivity does not, however, guarantee validity. For example, individuals taking the MMPI for employment purposes can give socially desirable answers to create a good impression. But in so doing they may also score high on a lie scale that assesses faking (as when people respond False to a universally true statement such as “I get angry sometimes”). The objectivity of the MMPI has contributed to its popularity and its translation into more than 100 languages.