Dynamic cycles of cognitive and brain development: Measuring growth in mind, brain, and education

Abstract

Mappings Single Abstractions Abstract Systems Rp2 28 24 20 16 12 Age in Years Figure 8.2 Cyclical spurts for cognitive development under optimal conditions. 130 K. W. Fischer //FS2/CUP/3-PAGINATION/FISH/2-PROOFS/3B2/9780521876735C08.3D 131 [127–150] 1.6.2006 9:10PM development and education, because they follow a common scale across domains. Skills in different domains demonstrate discontinuities along the same scale (Dawson-Tunik et al., 2005; Fischer & Bidell, 2006). The results are especially strong and clear for cognitive development and learning, where research has clearly demonstrated a single common scale for skill complexity across diverse contents and with different methods for assessing patterns of change. Cognitive development moves along this scale whatever the domain, just as temperature follows one scale whether the object measured is a sick child, a glacier, a boiling pot of water, a volcano, or the surface of the sun. The complexity scale provides a useful ruler for educational assessments, applying for different domains, for learners and teachers, for tests and curricula (Bidell & Fischer, 1992; Dawson-Tunik & Stein, in press). It has proved useful even for tracking the ups and downs of learning a specific task, which is commonly called microdevelopment (Granott, Fischer, & Parziale, 2002). Understanding the growth patterns behind the scale requires first addressing a common misconception about development. Most people assume unconsciously that development involves progression along a ladder from one stage to the next. However, children and likewise adults develop not along a ladder but along a web of many strands. The common complexity scale across domains does not mean that development occurs in ladder-like stages. Figure 8.3 illustrates the web for three domains of development in adolescents and young adults – mathematics, self-in-relationships, and reflective judgment (Fischer et al., 2003). An individual constructs separate skills for each domain, including several different strands within each. All strands move along the same complexity scale, but the skills in one strand are independent of those in another. Sometimes strands differentiate into new, separate strands, and at other times they combine to form a new integrated strand. For some purposes skills in different domains such as reflective judgment and conceptions of self can be treated as simply separate, but as development proceeds, people often combine strands from different domains, connecting for example conceptions of self as a student with conceptions about how they know that something is true (the bases of knowledge – reflective judgment). In either case, the same complexity scale characterizes development along each strand, even though the strands involve separate skills. The same ruler measures the complexity, but this common ruler does not imply that all the skills are the same, any more than a common temperature reading means that a person with a given temperature contains the same heat energy as a summer day with that temperature. Developmental cycles of brain and cognition 131 //FS2/CUP/3-PAGINATION/FISH/2-PROOFS/3B2/9780521876735C08.3D 132 [127–150] 1.6.2006 9:10PM The growth cycle of skill construction appears in the web as clusters of discontinuities – angles, joinings, and separations of lines within the boxes marking the zones in which three new optimal levels emerge. These clusters capture changes for optimal performance, while ordinary, nonoptimal performance takes place at lower points along the strands. That is, the same person in the same domain or strand shows a different developmental level depending on whether he or she is performing at optimal or functional level (as shown in Figure 8.2). People do not act consistently at one level, even for a familiar domain such as conceptions of self. Their skills vary in complexity from minute to minute depending on contextual support, motivation, fatigue, and other factors. Cycles of cognitive development Cognitive development moves through ten levels between 4 months of age and early adulthood. The levels from childhood to adulthood, which are most relevant for education, are summarized in Table 8.1. Among the simplest, most compelling evidence for the levels is the spurts and drops in performance that occur for optimal performance at specific ages. Research on arithmetic, self concepts, reflective judgment, moral reasoning, classification, conservation, and many other tasks shows these Clusters marking cycles of optimal levels Self in relationships Reflective judgment Mathematics