Personality Assessment through Longitudinal Designs

Structure

The concept structure (what) refers to the more stable and enduring aspects of personality. Such structural concepts as response, habit, trait, and type have been popular in efforts to conceptualize what people are like. The concept of trait refers to the consistency of individual reponse to a variety of situations and focuses on interindividual differences and stability (of these interindividual differences). Another related question focuses on the organization of the structural units, e.g. in a hierarchy of these units and inter-and intraindividual stability of the organizational structure.

Process

The concept of process (why) refers to the dynamic motivational aspects and constructs which are considered to account for behaviour, e.g. in a large family of personality theories the organism is viewed as seeking a state of balance, homeostasis, or equilibrium.

Growth and Development

Growth and development (how) are related to the concept of structure and process, not only in terms of changes in structure and processes from infancy to maturity, but also – and this is a domain of increasing interest – from maturity to middle age and even to old age.

Again, growth and development are characterized by individual differences, up to the extreme of psychopathological behaviour: why are some people capable of coping with the stress of daily life and generally show high-level life-satisfaction, whereas others develop abnormal responses? Personality theory should suggest intervention strategies by which behaviour could be modified. Empirical research strategies should enable the researcher to differentiate stability and invariance from change in a reliable and valid way.

So, according to Pervin and John (2001), a complete theory of personality must take into account structure, process, development, psychopathology, and change.

The term development refers not only to those processes that are biologically programmed and inherent in the organism, but also to those in which the organism is irreversibly changed or transformed by interaction with the environment. [Page 709]As the result of one's life history with its accumulating record of adaptations both to biological and to social events, there is a continually changing basis within the individual for perceiving and responding to new events. According to Thomae (1970) personality can be defined as the essence of all events, which unite into an individual biography. From this perspective, development might be described as the individual history of life. Personality development, then, is conceptualized as a reflection of the attempts by the individual to maintain a sense of continuity. Striving for continuity is characterized by the subjective experience of the person's own development. In recent years, two broad classes of methodological techniques, referred to as person-centred methods, have been introduced in response to this challenge: bottom-up and top-down strategies. The bottom-up strategies begin with idiosyncratic individual histories, and the analytical steps identify important commonalities and differences across lives, leading to aggregation of histories into relatively homogeneous groups. The top-down strategies begin with coarse-grained descriptions of heterogeneous in terms of details of live histories – populations and partition them into progressively more homogeneous subgroups, each of which is described using information over time from multiple life domains. Developmental researchers are increasingly interested in the use of such person-centred methods. Thus, the aim of the investigation of development in middle and old age is not to discover universals, not to make predictions that will hold good over time, and certainly not to control, but, instead, to explicate contexts and thereby to achieve new insights and new understanding.

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