Entornos genéticos de BLEEs:

A widely shared goal is to find a universal taxonomy or classification system for sorting the vast array of human attributes into a relatively small set of fundamental dimensions or

categories on which most individual differences can be described. From this perspective, psychologists attempt to identify ‘‘the most important individual differences in mankind’’

(Goldberg, 1973, p. 1).

Psycholexical Approach

Researchers in this approach assume that the most significant individual differences—

those that are most important in daily human relationships—enter into the natural language of the culture as single-word trait terms. They use a variety of methods to identify basic trait terms in the language and to categorize them into smaller groupings.

This is an enormous classification task, given that English includes thousands of trait terms (over 18,000 in one count of the dictionary). The hope is that an extensive, well-organized vocabulary for describing human attributes in trait terms will lead to better theories of personality and better methods of personality assessment.

This research strategy is called the psycholexical approach. Its basic data are the words in the natural language that describe human qualities. In these studies, many people are asked to rate how well each of many trait terms describes or fits a particular person they know well. In some studies, this is a peer; in some studies, participants rate how well the words describe themselves. In each study, the results are then analyzed to see which sets of trait terms tend to cluster or ‘‘go together’’ when individuals are described. Using statistical procedures, the researchers try to specify a small number of factors or dimensions that seem to capture the common element among adjectives that are closely associated (e.g., Goldberg, 1990).

3.14 Describe the assumptions underlying the psycholexical approach to identifying the major traits that underlie personality.

Ambitious–

dominant

Arrogant–

calculating

Cold–

quarrelsome

Aloof–

introverted

Lazy–

submissive

Unassuming–

ingenuous Warm–

agreeable Gregarious–

extraverted

Figure 3.5 Wiggins’s (1980) taxonomy of the interpersonal domain.

Source: Wiggins, J. S. A psychological taxonomy of trait-descriptive terms: The interpersonal domain. Journal of Personality and Social Psychology, 37, 399, fig. 2. ” 1979 by the American Psychological Association.

Reprinted with permission.

Taxonomy of Human Attributes 䉳 59 This approach was illustrated in an early attempt to find a comprehensive taxonomy

of the domain of interpersonal behavior (Wiggins, 1979, 1980) that yielded the dimensions shown in Figure 3.5. Note that each dimension is bipolar, that is, has two opposite ends or poles. The dimensions are structured in a circular pattern like a pie.

Each pole is made up of a set of adjectives so that Ambitious (Dominant), for example, is defined with such terms as persevering, persistent, industrious. The opposite pole, Lazy (Submissive), includes such terms as unproductive, unthorough, unindustrious.

Wiggins reports that these dimensions fit well the results of earlier descriptions of the interpersonal domain (Leary, 1957). They seem to be reasonably robust and useful when different samples of people are rated on them and continue to be revised and refined (Wiggins, Phillips, & Trapnell, 1989).

The ‘‘Big Five’’ Trait Dimensions

For many years in the long search for a universal taxonomy of traits, researchers disagreed as to which personality dimensions they should use to describe personality.

Some proposed as many as 16; others, as few as two or three (Vernon, 1964). More recently, however, some consensus has grown among many researchers to focus on five dimensions of personality (Goldberg, 1992; John, 1990; McCrae & Costa, 1985, 1987, 1999) that emerge from ratings using English-language trait adjectives.

Trait terms number in the thousands, as a look at the dictionary makes clear. But they have to be simplified and organized to become manageable units for describing people systematically. Consider, for example, the mass of data yielded by responses to a self-report measure with 550 items answered by 100 persons. To extract order from such a stack of facts, investigators searching for underlying traits try to group responses into more basic clusters. For this purpose, many trait psychologists turn to factor analysis.

This is a mathematical procedure that helps to sort test responses into relatively homogeneous clusters of items that are highly correlated. Using this method, and working in the psycholexical approach, a number of researchers have reached reasonable agreement about the five types of dimensions or factors on which English trait terms may be clustered, often called the ‘‘Big Five Structure’’ (e.g., Goldberg, 1992; John, 1990).

Factor Analysis to Find Trait Dimensions: The NEO-PI-R and Big Five

Factor analysis is a very useful tool for reducing a large set of correlated measures to fewer unrelated or independent dimensions. As such, it can be a powerful aid to psychological research by clarifying which response patterns go together. Suppose, for example, that 50 students have answered 10 personality questionnaires, each of which contains 100 questions. A factor analysis of this mass of information can show which parts of the test performances go together. It essentially finds and connects the items that tend to ‘‘go together’’ (covary) with each of the other items in the total set. The analogy would be a procedure that allows you to go to a stack of several hundred unsorted books in the library and that finds and groups together those that are alike on certain dimensions (e.g., size, color, length, language, content areas) but different in other respects.

A series of pioneering studies (Norman, 1961, 1963; Tupes & Christal, 1958, 1961) investigated the factors obtained for diverse samples of people rated by their peers on rating scales. The scales themselves came from a condensed version of the thousands of trait names originally identified by Allport and Odbert’s search many years earlier for trait names in the dictionary. After much research, 20 scales were selected and many judges were asked to rate other people on them. The results were carefully factor analyzed.

TABLE 3.3 The Big Five Factors and Illustrative Components

Factor (Trait Dimension) Adjective Items^a

I. Neuroticism (N) Calm–worrying

(negative emotions—e.g., anxiety, depression) Unemotional–emotional Secure–insecure Not envious–jealous

II. Extraversion (E) Quiet–talkative

(versus closed-minded) Aloof–friendly

Inhibited–spontaneous Timid–bold

III. Openness to Experience (O) Conventional–original

(versus closed-minded) Unadventurous– daring

Conforming–independent Unartistic–artistic

IV. Agreeableness (A) Irritable–good natured

(versus antagonism) Uncooperative–helpful

Suspicious–trusting Critical–lenient

V. Conscientiousness (C) Careless–careful

Helpless–self-reliant Lax–scrupulous

Weak-willed–Goal-directed

aIllustrative adjectives describing the two ends of the scales that comprise the dimension.

Source: Adapted from McCrae, R. R., & Costa, P. T., Jr. (1987). Validation of the five-factor model of personality across instruments and observers. Journal of Personality and Social Psychology, 52, 81–90.

Essentially similar results were found in John, O. P. (1990). The big-five factor taxonomy: Dimensions of personality in the natural language and questionnaires. In L. A. Pervin (Ed.), Handbook of personality: Theory and research (pp. 66–100). New York: Guilford Press; and in Normak, W. T. (1963). Toward an adequate taxonomy of personality attributes: Replicated factor structure in peer nomination personality ratings. Journal of Abnormal and Social Psychology, 66, 574–583.

The same set of five relatively independent factors appeared consistently across several studies and continues to form the basis of what has become the Big Five Structure (e.g., Goldberg, 1992; John, 1990). It consists of five factors measured with a personality inventory now called the NEO-PI-R (Costa & McCrae, 1997), as shown in Table 3.3.

The Big Five factors include: Neuroticism (N), for example, worrying and

inse-3.15 How was factor analysis used to identify the Big Five traits that are thought by some theorists to describe personality? Describe the five factors using the acronym OCEAN to capture their first letters.

curity; Extraversion (E) or surgency (positive emotionality), as reflected by terms like friendly, talkative; Openness to experience (O); Agreeableness (A); and Conscien-tiousness (C). See Table 3.3 for descriptions of each factor. In the NEO-PI-R, each factor is also more finely described in terms of a number of different facets through which it may be expressed, illustrated in Table 3.4.

The Big Five resemble the dimensions initially proposed by Norman (1963) and found repeatedly in research, although sometimes given slightly different names. Each dimension includes a collection of bipolar rating scales, such as ‘‘calm–worrying’’ and

‘‘timid–bold,’’ that refer to types of feelings or behaviors. For each dimension, Table 3.3 gives examples of the adjectives describing the two ends of some of the rating scales used.

To illustrate the type of research that underlies the development of the Big Five, in one study, 187 college students rated how well each of 1,710 trait terms described him or her (Goldberg, 1991). Statistical analysis showed that these terms clustered into five major factors or dimensions much like the Big Five (McCrae & Costa, 1987). Thus, when people are described with trait terms like those shown in Table 3.3, a reliable clustering

Evidence and Issues 䉳 61 TABLE 3.4 Illustrative Facet Scales for the Big Five Factor

Neuroticism: anxiety, angry hostility, depression, impulsiveness, vulnerability

Extraversion: warmth, gregariousness, assertiveness, activity, excitement-seeking positive emotions

Openness to Experience: fantasy, aesthetics, feelings, actions, ideas, values

Agreeableness: trust, straightforwardness, altruism, compliance, modesty, tender-mindedness Conscientiousness: competence, order, dutifulness, achievement, striving, self-discipline, deliberation

Source: Reproduced by special permission of the Publisher, Psychological Assessment Resources, Inc., 16204 North Florida Avenue, Lutz, Florida 33549, from The NEO Personality Inventory—Revised, by Paul Costa and Robert McCrae, Copyright 1978, 1985, 1989, 1992 by PAR, Inc. Further reproduction is prohibited without permission of PAR, Inc.

occurs consisting of five large descriptive categories or factors, called super traits. This Big Five Structure seems to characterize major dimensions of personality in natural English-language words. A number of personality trait questionnaires and personality ratings using these types of trait terms provide descriptions of persons that seem to fit the Big Five reasonably (Costa & McCrae, 1992a; Costa, McCrae, & Dye, 1991).

Considerable stability over time has been demonstrated on trait ratings and ques-tionnaires related to the Big Five (e.g., McCrae & Costa, 1990) even for long time spans. Stability tends to be particularly high during the adult years (Costa & McCrae, 1997; McCrae & Costa, 1999). It is notable that in spite of the many changes that often occur in life structures during adulthood over long time periods—including the changes produced by marriage, children, divorce, residential and occupational moves, and health issues—the status of most individuals on the Big Five dimensions tends to show high stability (see Table 3.5).

3.16 How stable are the Big Five dimensions over time?

TABLE 3.5 Stability of NEO-PI Scales (Ages 25–56)

NEO-PI Scale Men Women

N (Neuroticism) .78 .85

E (Extraversion) .84 .75

O (Open minded) .87 .84

A (Agreeable) .64 .60

C (Conscientiousness) .83 .84

Note: Retest interval is 6 years for N, E, and O scales, 3 years for short forms of A and C scales.

Source: Adapted from Personality in Adulthood (p. 88), by R. R. McCrae and P. T.

Costa Jr., 1990, New York: Guilford Press.