Qualitative models in developmental analysis.

The logic of set theory is applied to the problem of developmental change providing a multiplicity of analytic frameworks. Three independent dimensions of sequence invariant models are described which correspond to between-person differences, within-person differences, and the relation of developmental elements. Within each dimension, various types of progression are identified as unitary or multiple (convergent, divergent, or parallel), simple or cumulative (partial or complete), and conjunctive or disjunctive. The resulting models are applied to selected current theories of development. The approach suggests the potential utility of applications of choice theory to developmental process. Conventional quantitative models of developmental analysis generally assume the meaning of traits, characteristics, or behaviors invariant from age period to age period. When applied to emergent characteristics or organizations , this assumption may obscure individual and developmental differences. As Loevinger (1966) stated: A useful purpose will rarely be served by classing together in regard to conformity those who have not yet grown into it, those who are not willing to conform, and those who have outgrown the stages, who are able to conform but do not need conformity to insure impulse control [p. 203]. An alternative to the conventional quantitative approach is qualitative analysis: A method which facilitates the description and interpretation of developmental ly exclusive characteristics and organizations. Unfortunately, qualitative analysis is confounded by a plethora of ill-defined terms which designate age-related change, while the general model of transformatio n is a one-step-at-atime, single-sequence movement. Development is thereby constrained to a lockstep process.