Assessment of Personality

1. Assessment of Personality

2. Measuring Personality 1. Personality can be measured in many different ways. Many people have seen personality tests in magazines or websites that claim people can learn about their personality based on what color, animal, or food they like. Many of these tests are not valid (e.g., they do not capture the psychological concept personality is supposed to represent).

3. Self-Report Questionnaires Self-report: The assumption behind this questionnaire that asks respondents what they are like is that people have a pretty good idea of how they typically think, feel, and behave. Therefore, if clear, direct questions are written about people’s personality, and the people answer honestly, researchers can learn a lot. Many people are familiar with the Myers-Briggs self-report questionnaire, but it is not an empirically valid personality questionnaire.

4. Face validity: Self-report questionnaires ask face-valid questions about personality. A face-valid question has no tricks or hidden agendas. It measures what it looks like it is measuring. Example: If a researcher wants to know if someone is extroverted, he or she can ask them “Do you tend to talk a lot?” “Do you like being around people?” etc.

5. Questionnaire design: Most personality questionnaires use Likert-type statements. (Likert was a U.S. psychologist (1903-1981) ).These are statements (e.g., “I am often anxious.”) on which the respondent indicates how strongly he/she agrees or disagrees with on a continuous scale (e.g., from 1 to 5, in which 1 is “strongly disagree” and 5 is “strongly agree”).

6. Strengths and Weaknesses of Self-Report People have a lot of information about themselves because they have seen themselves in many different situations over many years, and people have direct access to their own thoughts and feelings. However, people may not always tell the truth, especially when a lot is at stake, like in a job interview. People also may not always know the truth about themselves, especially for aspects of personality that are desirable or undesirable, like intelligence or rudeness.

7. Information Report Questionnaires Informant report questionnaires are completed by people who know the target (the person whose personality the researcher wants to know about) well. Informant report questionnaires are almost identical to self-report questionnaires. They also typically use Likert-type questions. The only difference is that instead of rating their agreement or disagreement with statements about themselves, informants rate their agreement or disagreement with statements about the target (e.g., “She/he is often anxious.”) Benefits of these include lots of information from many possible informants, and the fact that many traits depend on observation. However, finding informants close enough can be hard, and internal traits (anxiety, for example) can’t easily be seen.

8. Behavioral Measures A person’s personality can be measured by observing their behavior or the traces of their behavior. For example, ask people to wear a recorder that will record the sounds of their behavior as they go about their daily life. This has the advantage of capturing what people are like outside of the laboratory: Do they spend a lot of time interacting with others? Do they swear a lot? How friendly are they? Behavior is easy to observe and is both quantifiable and less subjective. However, it can be hard to determine a single personality trait from one behavior. Does many divorces mean low agreeableness, or quick to anger? Maybe neuroticism? Just plain “bad luck”?

9. Tests Unlike a personality questionnaire, a personality test is designed to ask questions that are not completely direct (i.e., not face valid). Tests try to get the answers to these questions by evaluating how someone answers specific questions. Personality tests don’t come out and ask what they really want to know. Instead, they ask indirect questions and interpret your answers to determine your personality. For example, instead of asking something like “how narcissistic are you” or “how high of an opinion do you have of yourself” they might instead ask “if you were king of the world, would it be a better place?” If you answer yes, that might register as narcissistic.

10. Projective Tests Projective tests are special kinds of tests based on the idea that if you give people an ambiguous stimulus and ask them to describe it, their answer will tell you something about their personality. The most well-known example is the Rorschach test. Psychologists who use the Rorschach test believe people’s descriptions of what they see in ink blots tell something about their personality. The test is linked to psychoanalysis. Another example of projective tests is the Thematic Apperception Test, also called the Picture Story Exercise. There is little evidence that any of these tests are valid.

11. Objective Tests Most personality tests are “objective tests,” so-named because they are not projective (not because they are especially objective). These include any tests with yes/no response options, numerical response options, etc. The rational method of creating objective tests: Researchers write items that seem like they would be a good measure of the personality trait they want to measure. If you wanted to study Narcissism, you’d ask questions that’d reveal narcissistic tendencies. The empirical method of creating objective tests is to write many items, try them all out, and keep the ones that are actually a good measure of the trait the researcher wants to measure. Throw basically any question into a test, and through many cycles, keep the ones that get results. This can lead to some weird questions.

12. “Do you prefer baths or showers?” -From the Minnesota Multiphasic Personality Inventory, one of the only officially used personality test in the U.S.

13. Characteristics of a Good Personality Measure Reliability: The consistency of a measurement. Reliability does not indicate how accurate or true the measure is. Reliability is about consistency, not about accuracy Test-Retest Reliability: When you get similar results when you measure someone’s personality using measure X at time 1 and then again at time 2. If you step on a scale and it tells you you weigh 50 pounds, and then 5 minutes later you step on it again, and once again it states 50 pounds, it’s reliable, just not valid (or you are very small).

14. Internal consistency applies to measures with multiple items (e.g., a self-report questionnaire with 10 items). Internal consistency is the degree to which the various items produce similar scores (i.e., measure the same thing). There are many ways to measure internal consistency, including “split-half reliability,” which refers to the consistency between one half of the items (e.g., all the odd-numbered items) and the other half of the items on the same measure (e.g., all the even-numbered items). Parallel forms reliability refers to the consistency across the different forms when there are different versions, or “forms,” of a scale. Would people get the same score if given either Form A or Form B? The SAT is an example of a measure with parallel forms.

15. Characteristics, Part Two Validity: The accuracy of a measure. For a measure to be valid, it must be reliable. It should consistently give the right answer. (So, all valid tests are reliable, but not all reliable tests are valid) Ways to test include: Convergent validity: This determines if the measure agrees with other measures of the same personality trait. Does one type of extroversion test produce similar results to other extroversion tests? Discriminant validity: This determines if the measure is unrelated to other measures of unrelated traits. You have to prove that the trait being measured (extroversion) is not related to the measure of a different trait (like self-esteem).

16. Predictive validity: This determines if the measure helps predict behaviors and outcomes related to the trait. Does the extroversion test predict things extroversion tests should, such as talkativeness, Facebook friends, etc.? Generalizability: This determines if the measure is equally valid for all people/situations/times/places. Sometimes a measure can be valid for certain groups of people (e.g., Caucasians, college students, women, adolescents) but not others. Therefore, it is important to know exactly for which groups of people the measure is valid.