He labeled the three dimensions as introversion-extraversion, neuroticisms and psychoticism.
Traits account for regularities in the functioning of a person across situations and overtime. Allport places personal dispositions on a continuum from those that are most central to those that are of only peripheral importance to a person. There are three levels of personal traits or dispositions.
The first one is a cardinal trait that expresses a disposition that every act is traceable to its influence and it dominated an individual. The second is central traits (e.g. honesty, kindness, and assertiveness) express dispositions that cover a more limited range of situations than is true for cardinal traits. The last one is secondary traits represent dispositions that are the least salient and more restricted in their applicability.
Allport suggested that behavior expressed the action of many traits, that conflicting dispositions can exist within the person, and the traits are expressed in part by the person's selection of situations as opposed to his or her response to situation. Hence, traits are different from states and activities, which describe those aspects of personality that are temporary, brief, and caused by external circumstances. For example, the introverted person may behave in an extraverted fashion in certain situations. .
As stated before, source traits can predict personality of a person in a given situation, but this must be distinguished from surface traits. Surface traits express behaviors that on a superficial level may appear to go together and do not have a common cause. Surface traits and source traits are one of the two important distinctions between traits and the second one is among ability traits, temperament traits, and dynamic traits.
Ability, temperament, and dynamic traits are seen as capturing the major stable elements of personality. Ability traits relate to skills and abilities that allow the individual to function effectively.