Trait Theory: The Basis of Human Personality

There is an ongoing debate in psychology over the nature of personality and human behavior. This debate over personality theory is epitomized by two different approaches: one based on trait theory and the other on situationism. Some psychologists and theorists alike subscribe to the view that human personality is based on situationism, the idea that the behavior of humans is dictated by the aspects of a particular situation, and not by any innate characteristics of individuals.

While some psychologists use changing situations to explain inconsistencies in people's behavior, others point to inherent differences in personality traits. Trait psychologists believe that all types of personalities stem from one basic group of characteristics and individual personalities are just selections of a few of those available traits, which are biological in nature.

The Diagnostic and Statistical Manual of Mental Disorders-IV defines traits as patterns of perceiving, relating to, and thinking about the environment and oneself that are exhibited in a wide range of social and personal contexts. These patterns, common to all humans, are believed by trait theorists to be the foundation for all types of demonstrated human behaviors, emotions, and thought. The validity of trait theory has been consistently demonstrated by proven research; its view that personality is stable throughout diverse situations is one founded on correct scientific evidence. Trait theory, and not situationism, is the correct view in personality theory.

The five-factor model of personality, known as the Big Five, consists of five broad categories of personality traits: agreeableness, conscientiousness, extraversion, neuroticism, and openness to experience. This model has been backed by an enormous body of research and shown to be common among all people and easily identifiable by outsiders. The ability of five-factor tests to be used successfully reveals the presence of personality traits that exist in all humans; this indicates that trait theory is the correct viewpoint in the personality theory debate.

A research study conducted and published by Paul T. Costa Jr. and Robert R. McCrae, "Validation of the Five-factor Model of Personality Across Instruments and Observers attests to the effectiveness of the five-factor measurement of human personality. In the study, 275 adults were administered a self-reporting type of personality test, the NEO Inventory, and adjective-rating scales. This group of subjects was then given instruction to select three or four of their peers who knew them well, who would be charged with rating their personalities. The subjects ended up contacting 1,075 people, with 747 responding and providing rating information about the subjects on a NEO Personality Form R and an adjective-rating scale; of those contacted, this segment represented 69% (Costa & McCrae, 1985).

The study found strong relationships among the scores given by different peer reviewers to the same person, and between peer-graded and self-reported personality scores. All intraclass "peer reviews of the same individual" were shown to be statistically significant for the five major factors of personality tested. The range of these correlations was from .30 to .65; the median result was .38, indicating a positive correlation between the scores (Costa & McCrae, 1985). Additionally, the study found a substantial statistical relation between peer scores and self-reported scores, especially on the NEO Personality Inventory. The correlations for neuroticism, extraversion, openness, and conscientiousness were .51, .56, .67, and .58, respectively, demonstrating a strong positive correlation between self-reported and peer-reviewed scores on the measure of personality. Even agreeableness, which had a correlation coefficient that was considerably lower than the others at .28, hinted at a relationship between the two scores (Costa & McCrae, 1985).

The findings of this study support the continued usage and expansion of the five-factor model in existing personality research. The underlying theme of the study is that personality's traits are common to all people and can very easily be identifiable to outsiders. The results found in the study not only indicate the strength of five-factor tests themselves, but confirm the model's existence as a more or less comprehensive taxonomy of personal traits. (Costa & McCrae, 1985). The fact that these personal traits can be successfully measured substantiates their existence, indicating that trait theory is correct.

Aspects of human personality can be shown as stable and consistent across various cultures. This indicates that personality is shaped not by outside environment or situation, but by innate traits produced by genetics and heredity.

A study by Robert R. McCrae and Antonio Terracciano, "Universal Features of Personality Traits from the Observer's Perspective: Data from 50 Cultures demonstrates this uniformity of personality traits, even in vastly dissimilar environments and situations. The study utilizes a subject group of college students immersed in fifty different cultures, ranging from the Portuguese society in Brazil to the Arabic culture in Kuwait. The lowest number of observed participants in any country was 106 in Northern Ireland; the highest number was in the United States, with 909 (McCrae & Terracciano, 2005). This larger sample size for America "representing 7.6 % of the study's 11,985 participants" helps form a strong basis for future comparisons made between the culture in America and those in foreign countries.

The third-person type of the NEO-PI was used by the college students to assemble ratings of their selected participants. The participants themselves utilized a 240-question NEO-PI Form R test to generate their personality scores in the five factors.

Factor-structured analysis demonstrated the connection between the self-reported and observer-graded scores across an incredible array of cultures. Classic trends in personality perception" notably the more positive grading nature of women than men when evaluating others" withstand any cultural barriers that were thought to exist; statistically significant variations in women's self-rating and observer assessment, especially in neuroticism's impulsiveness subdivision, were found in the study, just as in classic domestic studies (McCrae and Terrecciano, 2005). Variation due to differences in age and education level was found in the study, in almost the same proportions across all cultures.

Earlier work by McCrae focused on and demonstrated the innateness of personality traits for people within the United States; this cross-cultural study demonstrates the near invulnerability of individual personality to the influence of outside environments and situations by comparing the results of people whose living situations could not be more different. This study serves as evidence of a biological foundation for personality, and thus a trait theory. The existence of inborn traits is strongly supported by the consistency of personality evaluation among different societies across the world, transcending all possible limitations of language and differences in culture.

There exists a clear link between the occurrence of psychological disorders and the possession of certain levels of personality traits. This provides further support for an unchanging biological state of personality, since it can serve as the fuel for observable and measurable disorders.

In his study "DSM-III-R Personality Disorders and the Five-Factor Model of Personality: An Empirical Comparison", Timothy Trull was able to demonstrate a connection between the possession of certain five-factor personality traits and the occurrence of psychological disorders.

The subjects of the study were fifty-four psychiatric outpatients of two clinics in the Midwest. Certain restrictions were in place when the group was assembled: participants must have been at least eighteen years old and free of any substance-abuse problems, for example. Seventy-two percent of the sample's members were women, and the mean age of the group was 28.18.

They were administered the self-reporting personality tests NEO-PI, MMPI-PD scales, and PDQ-R. The scores generated by each of these tests were then compared to the type of personality disorder symptoms from which the patient suffered. Strong correlations were found between domains on the personality tests and type of psychological disorder present. The disorder symptoms, when run as a multiple-regression analysis compared to the NEO-PI scores, for example, showed no correlation lower than .38. Certain traits were especially prone to having specific disorder symptoms: Borderline, for instance, had a .6 correlation with high neuroticism and a -.45 correlation with low agreeableness (Trull, 1992).

A popular criticism of trait theory is that it is a bad predictor of future behavior and performance. The strength of the correlations in Trull's study between disorders and scores on personality evaluations hint that this is unjust, but the multiple-regression tests used in the research attack the criticism directly. The five domain scores of these multiple-regression tests were very strongly correlated with symptoms of the disorders, with the relationships calculated as all positive correlations above .37. These findings are easily applicable into the real-life scenarios where opponents of trait theory cite the idea as weak. For instance, people who possess the traits that the study found indicative of a Narcissist" low neuroticism, very high extraversion, and high openness" will likely not perform well in a job that requires a lot of teamwork and cooperation. Potential employers can, as a result, screen applicants for these types of jobs to ensure that their measured personalities are not suggestive of the problematic disorder.

The debate over personality theory has been refined to a debate between two opposing sides: one in favor of trait theory, and one in support of situationism. These two approaches both seek a way of explaining human personality and behavior. Trait theory is the correct approach in the personality theory debate because of several factors, among them: the proven success of five-factor personality models in measuring traits, both from observers' evaluations and self-reported tests; the ability of these models to withstand any challenges across cultures and still provide consistent, accurate measurements of personality; the proven presence of a clear, identifiable link between psychological disorders and personality traits; and the potential for personality test scores to predict future performance and behavior. The research into these areas has attested to the existence of a group of biological traits that forms the foundation for human personality as we view it in the world today.

WORKS CITED

McCrae, R. R., & Costa, P. T. (1987). Validation of the five-factor model of personality

across instruments and observers. Journal of personality and social psychology, 52(1),81-90. Retrieved November 7, 2006, from PsycARTICLES database.

McCrae, R. R., Terracciano, A. (2005). Universal features of personality traits from the

observer's perspective: Data from 50 cultures. Journal of personality and social

psychology, 88(3), 547-561. Retrieved November 7, 2006, from PsycARTICLES database.

Trull, T. J. (1992). DSM-III-R personality disorders and the five-factor model of

personality: An empirical comparison. Journal of abnormal psychology, 101(3), 553-560.Retrieved November 7, 2006, from PsycARTICLES database.