THE DEVELOPMENT OF EXECUTIVE FUNCTION IN EARLY ...

(2000) pointed out, even in the DCCS children need to understand the experimenter's intention to signal that the
rules have changed.
To date, theories of executive function have focused almost exclusively on the processing of information
defined objectively from a third-person perspective. Eventually, however, if we are to take seriously the
suggestion that executive function corresponds to consciously controlled behavior, we must attempt to reconcile
our third-person descriptions of cognition and behavior with first-person, intentional characterizations of
meaningful thought. Although this objective has largely been lost since the days of Baldwin (1897) and Piaget
(1963), it is increasingly being rediscovered, both in developmental psychology (e.g., Barresi & Moore, 1996;
Bloom & Tinker, 2001; Deak, 2000; Overton, 2003) and in other areas of psychology (e.g., Thompson &
Varela, 2001; Varela, 1996).
REVISED CCC THEORY
The findings from this Monograph support a revision of the CCC theory in which the key claims of CCC theory
are retained. These claims include the following: (a) Executive function is best viewed functionally, as an
outcome, not an explanatory construct. (b) Children's plans are assumed to correspond literally to rules,
formulated in potentially silent self-directed speech. (c) In response to particular problems, children formulate
rule systems in an ad hoc fashion and use these rules systems to regulate their inferences and action, and select
particular pieces of information for maintainence in working memory. (d) There are several age-related
increases in the highest possible complexity of children's rule systems, and these increases can be observed in
many domains of behavior. (e) Complexity is measured by the number of levels of embedding in children's rule
systems. (f) Age-related changes in complexity are made possible by age-related changes in reflection that in
turn might be dependent on the experience-dependent maturation of prefrontal cortex. Based on evidence from
animal studies (e.g., see Huttenlocher, 2002), it is very likely that the maturation of prefrontal cortex is
influenced by environmental stimulation. Moreover, there is evidence that parents' verbal scaffolding of
children's play is related to their executive function skills (Landry, Miller-Loncar, Smith, & Swank, 2002), and
training studies designed to improve children's executive function have been successful (e.g., Dowsett &
Livesey, 2000; Kloo & Perner, in press). Clearly, the role of the environment in general, and parent-child
interaction in particular, on the development of executive function needs to be examined in more detail.
The revised CCC theory (the CCC-r) adds to the original theory in several ways. It specifies more clearly the
circumstances in which children will have difficulty using rules at various levels of complexity, and it provides
a more detailed account of how to determine the complexity of rules required in a task. It takes account not only
of the activation of rules as a function of experience but also the inhibition of rules. Finally, insofar as the CCCr
theory takes intentionality seriously, it represents an integration of the CCC theory with the Levels of
Consciousness (LOG) Model (e.g., Zelazo, 1999, 2000; P. R. Zelazo & P. D. Zelazo, 1998). CCC theory shows
how age-related changes in executive function—considered as a functional construct are due to age-related
changes in the maximum complexity of the rules that children can formulate and use when solving problems.
The LOC model shows how these age-related changes in maximum rule complexity are, in turn, made possible
by age-related increases in the degree to which children can consciously reflect on the rules they represent (i.e.,
age-related increases in children's highest level of consciousness; Zelazo, 1999, 2000, in press). Together, the
CCC theory and the LOC model provide a framework for an intentionalistic, but still scientifically tractable,
account of executive function (Frye & Zelazo, 2003).
The LOG model is an information-processing model designed to capture the development of consciousness and
explain its role in executive function. As an information processing model, it traces the flow of information
through a functional system—in this case, illustrating the way in which intentional objects (i .e.,
representations) are operated on as they come to figure in the conscious control of behavior. As a developmental
model, the LOC model depicts the way in which this functional system changes in the course of ontogeny, and
shows the consequences of these changes for executive function. According to this model, higher levels of