Other forms of personality assessment.

Other paper-and-pencil methods of measuring personality are available that do not use behavior descriptive statements or adjectives as items. There is a whole class of personality instruments known collectively as projective tests. These include such measures as the Rorschach inkblot test, the Thematic Apperception Test, and the Incomplete Sentences Task. The assumption underlying projective tests is that a respondent's interpretation of an ambiguous stimulus is revealing of his or her personality dispositions. For example, the image a person sees in an inkblot may be indicative of his or her level of anxiety. Or the story one makes up when asked to describe what is happening in a picture of two people talking could reveal the person's level of self-esteem.

Projective tests are thought to enjoy the advantage of being relatively immune to social desirability responding and other forms of motivated distortion. The reason is that respondents generally do not know which responses to give to the ambiguous stimuli if they are intent on misrepresenting their personality characteristics in a particular direction. A major disadvantage of projective tests is related to subjectivity in scoring and interpreting respondent protocols. Despite the fact that formal training procedures are typically required for the administration of such tests (arguably a disadvantage in itself), differences in the judgments of scorers can lead to disagreements among them, even when evaluating the same protocols. This problem then raises broader issues concerning the reliability and the validity of the resultant test scores.

Questionnaires, tests, and inventories are not the only ways in which personality has been assessed. Direct behavior observation has been recommended by some as being superior to self-report, paper-and-pencil measures of traits. As mentioned earlier, however, such direct observations are difficult to obtain in sufficient numbers to yield reliable estimates of personality trait scores. Moreover, the difference in the quality of assessments by direct observation versus self-report questionnaire might not justify the added cost of the former. Self-reports of behavior have sometimes been supplemented with other-reports. For example, an expert rater who is familiar with a person's real-life behaviors (e.g., close acquaintance, coworker, clinician) might be asked to describe that person on a standard personality questionnaire. Presumably, such other-reports are less susceptible to misrepresentation than are self-reports.

Some researchers believe that the best prospect for the future of personality assessment lies in the search for individual differences in quantifiable physical attributes. People high in extroversion, for example, have been found to differ in several material respects from those high in introversion (i.e., low in extroversion). Extroverts, compared to introverts, are more easily distracted from a problem, are more tolerant of pain, are worse at signal detection tasks, and have quicker physiological responsiveness but lower levels of cortical activity. One theory is that introverts and extroverts differ fundamentally in their levels of central nervous system arousal – a physiological state that is proposed to be genetically determined, the basis of most extroversionrelated behavior differences, and potentially measurable by electro-mechanical instruments. – SVP

▶ See also PAPER-AND-PENCIL TESTS, RELIABILITY, and VALIDITY