WRAPPING IT UP

SUMMARY

Psychology’s Emphasis on Method

Psychology emphasizes the methods by which knowledge can be obtained. Knowledge about methods is necessary for conducting research, and also for understanding the results of research done by others.
Science is the seeking of new knowledge, not the cataloging of facts already known. Technical training conveys current knowledge about a subject, so that the knowledge can be applied. Scientific education, by contrast, focuses on how to find out what is not yet known.

Personality Data

In order to study personality, first you must look at it: All science begins with observation. The observations a scientist makes and expresses as numbers are data.
For the scientific study of personality, four types of data are available. Each type has advantages and disadvantages.
S (self-judgment) data comprise a person’s self-judgments as assessments of their personality. The advantages of S-data are that individuals have (in principle) a large amount of information about their own behavior; that individuals have unique access to their own thoughts, feelings, and intentions; that some kinds of S-data are true by definition (e.g., self-esteem); that S-data also have a causal force all their own; and that S-data are simple and easy to gather. The disadvantages are that people sometimes make errors or have biases in self-reports, and that S-data may be so easy to obtain that psychologists rely on them too much.
I (informant) data comprise the judgments of knowledgeable acquaintances about the personality traits of the person being studied. The advantages of I-data are that there is a large amount of information on which informants’ judgments are potentially based; that this information comes from real life; that informants can use common sense; that some kinds of I-data are true by definition (e.g., likeability); and that the judgments of people who know the person are important because they affect reputation, opportunities, and expectancies. The disadvantages of I-data are that no informant knows everything about another person; that informants’ judgments can be subject to random errors, such as forgetting; and that judgments can be systematically biased.
L (life) data comprise observable life outcomes, such as health, educational attainment, or economic status. L-data have the advantages of being objective and verifiable, as well as often being intrinsically important and potentially psychologically relevant, but they have the disadvantages of being determined by many different factors and are sometimes affected by the social environment as much or more than the individual’s personality.
B (behavioral) data comprise direct observations of a person doing something. Behavior may be observed in the person’s natural environment or an artificial setting constructed in a psychological laboratory. Behaviors can include words spoken, actions performed, and even physiological responses. The advantages of B-data are that they can tap into many different kinds of behaviors, including those that might not occur or be easily measured in ordinary life; and that they are obtained through direct observation, and so are, in that sense, objective. B-data have two disadvantages. First, they are difficult and expensive to gather. Second, for all their superficial objectivity, it is still not always clear what they mean psychologically.

Personality Assessment

Personality assessment is a frequent activity of industrial and clinical psychologists and researchers.
Personality testing is a big business that can have important consequences. But some personality tests are useless or even fraudulent, so it is important to understand how they are constructed and how they are used.
Some personality tests yield S-data and others yield B-data, but a more common distinction is between projective tests and objective tests. All projective tests yield B-data; most but not all objective tests yield S-data.
Projective tests seek insight into personality by presenting participants with ambiguous stimuli and interpreting their open-ended responses.
Objective tests ask participants specific questions and assess personality on the basis of the participants’ choices among predetermined options such as True or False, and Yes or No.
Objective tests can be constructed by rational, factor analytic, or empirical methods; the state of the art is to combine all three methods.

THINK ABOUT IT

If you wanted to know all about the personality of the person sitting next to you, what would you do?
In your opinion, is there anything about another person that is impossible to know? Is there anything that is unethical to know?
To assess the degree that someone is “sociable” would seem easy to do using S-data or I-data. How might you assess this trait using L-data or B-data?
Can you think of kinds of observations—data—that you could gather about a person that would fall outside of the BLIS scheme? Which of the four categories comes closest to describing these data?
An experimenter gives a subject a set of 10 impossible-to-solve mathematical problems. The experimenter times how long the subject works on the problems before giving up on the task. The minutes-and-seconds measure the experimenter has taken is, of course, B-data. The experimenter calls this measure “a real, behavioral measure of persistence.” What is right and wrong about this label?
People sometimes describe themselves differently than they are described by others (a discrepancy between S-data and I-data), and they sometimes describe themselves differently from how they act (a discrepancy between S-data and B-data). Why might this happen? When these kinds of data disagree with each other, which would you tend to believe?
Are some kinds of data “privileged” for some kinds of questions? For example, if a person claims to be happy (S-data), but acquaintances say the person is unhappy (I-data), is it possible that the I-data could be more valid than the S-data? Would it be meaningful to say something like, “You’re not as happy as you think you are”?
If an attribute like “happiness” can most appropriately (or only) be assessed with S-data, are other attributes of personality best (or only) assessable via I-data, L-data, or B-data?
Is research done with the predominantly White college students in Western cultures also relevant to members of other ethnic groups or to people who live in different cultures? In what areas would you expect to find the most differences?
If you wanted to understand someone’s personality and could ask the person only three questions, what would those questions be? What would the answers reveal?
How would you choose someone to be your roommate? Your employee? A date? Would personality traits be relevant to your choice? How would you evaluate those traits?
Have you ever taken a personality test? Did the results seem accurate? Were the results useful? Did they tell you anything you did not already know?
If you were being considered for a job you wanted very much, would you prefer the decision to be based on a personality test score or the employer’s subjective judgment of you?
Advocates of projective tests claim they can measure motives that the person taking the test might not be consciously aware of. What do you think of this claim? Can you have motives you don’t know you have?

SUGGESTED RESOURCES

American Psychological Association (2020). Publication Manual of the American Psychological Association (7th ed.). American Psychological Association.

This sets the standards that must be followed for all articles in journals published by the American Psychological Association, and most other psychological journals follow it too. The book is full of information and advice on the conduct, analysis, and reporting of psychological research. Every aspiring psychologist should have a copy. While the book is not available for free (the Manual is an important source of revenue for APA), a lot of useful and updated information is available, without cost, at www.apastyle.org/manual.

Cronbach, L. J., & Meehl, P. E. (1955). Construct validity in psychological tests. Psychological Bulletin, 52, 281–302.

A difficult read, but the classic presentation of how personality psychologists think about the validity of their measurements. One of the most influential methodological articles ever published.

Wiggins, J. S. (1973). Personality and prediction: Principles of personality assessment. Addison-Wesley.

The classic textbook for personality psychologists, including material of methodological as well as substantive interest. Pretty much everything your present author knows about psychological measurement, he learned from reading this book. Like a true classic, the book has maintained its interest and value with age.

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research: Exploration of the unknown; finding out something that nobody knew before one discovered it.
Funder’s Second Law: There are no perfect indicators of personality; there are only clues, and clues are always ambiguous.
Funder’s Third Law: Something beats nothing, two times out of three.
S-data: Self-judgments, or ratings that people provide of their own personality attributes or behavior.
self-verification: The process by which people try to bring others to treat them in a manner that confirms their self-conceptions.
I-data: Informants’ data, or judgments made by knowledgeable informants about general attributes of an individual’s personality.
expectancy effect: The tendency for someone to become the kind of person others expect them to be; also known as a self-fulfilling prophecy and behavioral confirmation.
behavioral confirmation: The self-fulfilling prophecy tendency for a person to become the kind of person others expect them to be; also called the expectancy effect.
L-data: Life data, or more or less easily verifiable, concrete, real-life outcomes, which are of possible psychological significance.
B-data: Behavioral data, or direct observations of another’s behavior that are translated directly or nearly directly into numerical form. B-data can be gathered in natural or contrived (experimental) settings.
projective test: A personality test that asks the client to interpret a meaningless or ambiguous stimulus.
projective hypothesis: The idea that if a person is asked to interpret an ambiguous stimulus, the answer will indicate the person’s needs, feelings, thought processes, or other hidden aspects of the mind.
objective test: A personality test that consists of a list of questions to be answered by the subject as True or False, Yes or No, or along a numeric scale (e.g., 1 to 7).
rational method: A method of personality test construction in which items are written based on their apparent or “face” relationship to the trait being measured.
factor analytic method: A method of personality test construction in which items are grouped together on the basis of factor analysis.
empirical method: A method of personality test construction based on comparing answers given by members of different criterion groups.
face validity: The degree to which an assessment instrument, such as a questionnaire, on its face appears to measure what it is intended to measure. For example, a face-valid measure of sociability might ask about attendance at parties.
factor analysis: A statistical technique for finding clusters of related traits, tests, or items.