Traits in practice: Objective reality and influences on behavior

The central question for this section to address is: Are traits of use in practice and to what extent? This is an important question because, after all, traits are hypothetical constructs, so neither their existence nor their impacts on behavior should be taken for granted. One further question arises from this: How can a postulated attribute such as a trait and its influence be verified in the real world? Guidelines for the validation of theoretical constructs like traits were developed during the 1950s14_{, with important contributions being: Technical Recommendations}

for Psychological Tests and Diagnostic Techniques – as collated by the American

Psychological Association (1954), Cronbach and Meehl (1955), and Loevinger (1957), which together detailed the fundamental principles behind construct validation. According to Cronbach and Meehl (1955), a construct exists only as an “open concept,” which is defined implicitly using a “network of laws.” This network of laws may refer to the relationships between the construct under consideration and other constructs, or the links between the construct in question and observable variables. When the construct under consideration is fairly new, it may be defined only by a few associations. Over time, the “network of laws” defining a given construct will be enriched by means of dynamic processes through which the network is further defined and elaborated as new empirical findings accumulate over time. It should be noted that the validation of a psychological construct resembles general scientific procedures used for developing and testing theories. The point to be made here is that traits are also an open concept, so we can only validate the workings and existence of traits by subjecting them to the relevant network of laws, that is, their relationship to other constructs and/or observable variables.

What does the evidence say regarding the reality of traits and their influence on people’s behavior? These very same questions were at the center of the “person-situation” debate that

14 _{Before that, psychologists were occupying themselves with criterion-oriented validity tests (Cronbach and Meehl}

1955, p. 281ff.). The procedure used in these tests is simple. Test administrators conduct the measurement, obtain independent criteria, and compute the level of correlation between the test results and the selected criteria. An intelligence test; for example, is valid when its scores are correlated with criteria such as GPA records.

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characterized the development of both personality psychology and social psychology over two decades - the 1970s and 1980s. The person-situation debate was ignited by Walter Mischel’s

Personality and Assessment, published in 1968, the main message of which was that human

behavior is too inconsistent to make traits a meaningful construct (Mischel 1968; Mischel 1973). Mischel argued that individual behavior is determined by different situations, and; therefore, tends to vary across them. He stressed that behavior is highly situation specific, so personality traits cannot be applied to predict human behavior. The critique produced by Mischel became influential because of his convincing empirical evidence demonstrating that people tend to act in a manner inconsistent with their traits. He showed that people’s trait scores and their actual behavior do not usually correlate; and when they do, the correlation is generally weak - a correlation figure of 0.30 has been used as the upper boundary of the relationship between personality traits and behavior for some time. Mischel further argued that the inconsistent nature of human beings implies that there is no such thing as a trait disposition as suggested by trait psychologists.

Such harsh critiques offered by Mischel prompted trait psychologists to engage in two lines of research the first of which attempts to demonstrate that traits do exist as an “objective,” psychological attribute (Block 1977; McCrae and Costa 1987; Costa and McCrae 1988). The second line of research tries to show that trait-behavior correlation is, in fact, stronger than the presumed level of 0.30 (Epstein 1979; Epstein 1983; Epstein and O'Brien 1985). These two lines of research will be briefly reviewed in turn.

Following the first line of inquiry, proponents of trait psychology tested the existence of traits using either cross-observer or longitudinal studies. The rationale behind using cross- observer studies was that if traits are an objective reality, they must be “perceivable”, not only to the person in question, but also to others, such as parents, spouses, relatives, close friends and colleagues. The cross-observer validity of personality traits can be assessed when respondents are each rated by at least two observers - one of whom may be the subject. The rationale behind longitudinal research is that if there are such things as traits, they should be manifested in terms of the relative stability of individuals’ trait scores. This is because traits are relatively enduring characteristics among individuals. Traits must endure across situations and over time, otherwise one would not be able to distinguish traits from mental states. The typical method used in longitudinal studies is to administer the same personality inventory to the same person twice, with the duration between the two tests ranging from a number of weeks to a few years.

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Evidence suggests that satisfactory levels of convergence exist between self- and observer-rated personality tests (McCrae 1982; McCrae and Costa 1987); for example, McCrae and Costa (1987) administered the self- and observer-rated versions of two different trait instruments. In their study, the subjects were asked to nominate friends, neighbors and co- workers who were not their relatives, and the results showed substantial levels of agreement among different observers regarding the traits of the same subject. Agreement was also found between self-raters and peer-raters. The magnitude of the correlations ranged from 0.40 to 0.60, and the results held for both personality inventories. These results led authors to point to the existence of traits as objective psychological attributes, those that both groups of respondents could perceive somewhat accurately. The results were confirmed recently (Connolly et al. 2007).

Evidence from longitudinal studies has also showed that traits are somewhat stable overtime. Some longitudinal studies have suggested that traits exhibit their robustness over rather long periods of time, such as six years (Costa and McCrae 1988) or in some studies, 45 years (Soldz and Vaillant 1999). What makes things complicated for this form of inquiry is the perception of trait psychologists that individual traits are only relatively stable (Costa and McCrae 1997) - trait theorists do not expect individuals’ trait scores to remain stable throughout their lives. In fact, personality scientists believe that there are normative trait patterns that shift within individuals. For this reason, results from longitudinal studies cannot be meaningfully interpreted unless the normative shift among traits is revealed. Researchers have put significant effort into investigating the normative shifts among traits, and early evidence presented by McCrae and Costa (1994) suggested that after the age 30, individual traits become more stable. This proposal was widely accepted among trait psychologists until recently, when new evidence emerged showing that traits do change even in people over 30 years of age, and that patterns of personality development are unique for each person (Roberts and Mroczek 2008). Basically, this means that much more research is needed, and that the nature of trait development is far from settled. Until this research is carried out, evidence from longitudinal studies may provide only weak support for the objective reality of trait.

As to the second line of inquiry that attempt to investigate the predictive power of traits, evidence on trait-behavior correlations suggests that traits can predict behavior better than the 0.30 barrier mentioned previously. The average degree of correlation between a single trait and a behavior has been updated to around 0.40 (Nisbett 1980), which is already very close to the theoretically obtainable level of correlation between a specific trait and a specific behavior of 0.50 (Ahadi and Diener 1989; Strube 1991). Interestingly enough, the effect of a given

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“situation” on behavior is not stronger than that of a “person.” In a special issue of the Journal

of Research in Personality (2009 – issue 43), published to commemorate 40 years of the person-

situation debate, Funder (2009, p.120) noted that 0.40 represents about the same impact level as documented over a century of social-psychological research (Richard et al. 2003). Worse, some authors pointed out that while the “person” side of the debate can be defined with considerable specificity and validity, the issue of how to specify and measure “situations” is far from settled (Hogan 2009). Thus, the prediction of single behavioral acts cannot be expected to depend upon explanations drawn from a single situational variable.

In sum, traits seem to be a useful psychological concept in the real world. Driven by the critique on trait theory which were put forward during the 1970s, personality psychologists have since convincingly demonstrated that the concept of traits exists as objective psychological attributes and that traits do have a significant impact upon people’s behavior. Taken section 3.1.1, 3.1.2 and 3.1.3 together, it appears that the concept of personality in general and traits in particular, provides an appropriate conceptual basis for the investigation of the psychological characteristics of CVM respondents. First, traits hold an important role in the functioning of individuals, i.e. they give rise to behavior. Second, traits can be conveniently measured during a CVM survey through the use of personality inventories, and third, empirical evidence supports the assertion that traits exist as objective attributions and can be used to predict people’s behavior. For these reasons, the use of trait theory in this study would appear to have been justified.