ABSTRACT. We employ tools of complexity theory to examine the effect of cognitive
variables, such as working-memory capacity, degree of field dependence–independence,
developmental level and the mobility–fixity dimension. The nonlinear method correlates
the subjects’ rank-order achievement scores with each cognitive variable. From the achievement
scores in organic-synthesis problems of various mental demands, rank-order sequences
of the subjects, according to their scores, were generated, and in the place of each
subject, his/her score was replaced by the value of the corresponding cognitive variable.
Then each sequence was mapped onto a one-dimensional random walk, and when treated
as a dynamic flow, was found to possess fractal geometry, with characteristics depending
on the complexity of the problem. The findings were interpreted using concepts from
complexity theory, such as order, correlation exponents, and entropy. The method provides
meaningful results and adds to the understanding of information processing and the role of
cognitive variables within the frame of predictive models in problem solving. Although the
method is applied to a particular kind of problems (chemical, organic-synthesis problems),
it can be generalized to other problems, not only in chemistry, but also in other sciences
and in mathematics. Finally, the educational implications are discussed.