Before describing the major modern trait and type theories of personality the following key terms must be defined; trait, type and personality. A personality trait represents a continuous dimension and can be defined as a broad, stable and enduring characteristic which is used to explain behaviour (Phares&Chaplin, 1997). A personality type is defined by Lefton, (2000 p. 708} as a "personality category in which broad collections of traits are loosely tied together and interrelated" and which people can be grouped into. Personality can be broadly defined (Myers, 1986; Pervin&John, 2001)as the enduring characteristics of an individual that describe patterns of thinking, feelings and behaviour.
The major modern trait and type theories of Gordon Allport, Raymond Cattell, Hans Eysenck and the Big Five vary in their approach and methods in their attempts to understand personality, yet all share the belief that personality can be understood and individual's behaviour could be explained and described by the use of types and traits. The trait and type personality psychologists used three methods in identifying important traits and types; the lexical approach, meaning the more important a word is the more often it will appear in lang
Cattells factors (A) reservedoutgoing and (C) ego strength have been associated with various clinical disorders (Ryckman, 2000)Criticisms of Cattells theory focus on his reliance on self reporting tests which may reflect individuals biases and his use of unsubstantiated sources of data (LiebertSpiegler, 1990). He argued that a nomothetic approach, studying behaviour by establishing universal rules about human functioning in general, based on statistical information used to compare one person to another person or group, was useful in understanding peoples behaviour and functioning in general, but did not explain or increase the understanding of the individuals unique characteristics (Ryckman, 2000)Allports emphasis on idiographic approach to personality psychology attracted controversy and criticism amongst his peers who argued; that the study of uniqueness unnecessary in forming a scientific theory, that the idiographic approach is the starting point for a theory to become generalised and that general scientific rules are capable of developing understanding the individuals unique personality (Falk, 1963, cited in Monte, 1999. Criticisms of the trait theories revolve around the enormous number of traits and how to develop a theory and classification system. Dimension (3) Conscientiousness as classified by Norman, Goldberg and McCrae is also a generally accepted classification. Central traits describe the characteristics of a person which are noticeable in the person's interactions in their daily life and have less influence or control over an individual's behavior than a cardinal trait. The labels given by researchers to these five factors varied, according to how each researcher measured, defined and characterised each factor and this has led to various interpretations and criticisms of the big five factor model Goldberg, 1993, Phares, 1997. Eysenck defined introverts as individuals who are quite, introspective and direct their energy inward, extraverts as people who are sociable, like excitement and direct their energy outwards, emotional stabilityneuroticism as variations in levels and frequency of individuals becoming upset and psychotics as people who are emotionally unstableneurotic, lack feelings, are hostilecruel to others, do not understand the consequences of their actions and or fear punishment (Carver, 1998). Most researchers agree with Eysencks classification and definition of dimension (1) IntroversionExtroversion and dimension (4)NeuroticismEmotionality. A cardinal trait exerts a significant influence in the individuals existence, affecting most aspects or actions in the individual's life. Cattells 16PF most important source traits are Factor (A), reservedoutgoing (which resembles Eysenecks introversionextraversion dimension), (B) intelligence, and Cattells factor (C), ego strength (which resembles Eysenecks emotionalitystability dimension). The five-factor model began to develop when first Fiske (1949 cited in Goldberg, 1993) was unable to replicate Cattell 16 PF and later Tupes and Christal (1958,1961 cited in Goldberg, 1993 analyised results from Cattells studies and found five replicable factors (Goldberg, 1993). Hans Eysenecks three factor type theory focuses on two basic personality dimensions or super traits; IntroversionExtraversion, NeuroticismEmotionality stability and a third personality dimension of Psychotism (Carver, 1998; LiebertSpiegler, 1990). Cattell believed that behaviour could be predicted more accurately once the major source traits of an individual have been identified (Ryckman, 2000). Raymond Cattell grouped traits together that had a similar meaning using factor analysis, a statistical procedure to locate a smaller number of factors in the larger personality inventory of traits. Dimension (5) has been classified as Intellect by Digman and Takemoto-Chock, Goldberg, intelligence by Borgatta and Openness to experience by Costa and McCrae and this dimensions classification is the most controversial of the five factors(Digman, 1990).