THE DEVELOPMENT OF EXECUTIVE FUNCTION IN EARLY ...

Research on executive function is properly concerned with intentionality not only in Brentano's (1874/1973)
sense, but also in the everyday sense. Executive function is simply goal-directed problem solving, and in
understanding the psychological processes that underlie executive function and bring it about, one needs to take
account of the content and directedness of an agent's intentional states (e.g., beliefs, desires, goals, intentions).
Although approaches to executive function and related phenomena have long recognized a distinction between
effortful, controlled processes, on the one hand, and automatic, stimulus-driven processes, on the other (e.g.,
Hasher & Zacks, 1984; Logan, 1988; Norman & Shallice, 1986; Ponser & Snyder, 1975; Shiffrin & Schneider,
1977), it is only recently that researchers have begun to address controlled processes in terms of broader
conceptions of intentionality. Examples can be seen in the adult literature on task switching (Allport & Wylie,
2000; Goschke, 2000). In the task switching paradigm, participants alternate between performing one task (e.g.,
naming the color in which a word is printed, as in a Stroop task) and performing a second task that requires
competing responses to the same stimuli (e.g., reading the color word; see Allport & Wylie, 2000). A common
finding is that reaction times increase in the trial following the switch (i.e., there is a switch cost). To explain
these switch costs, researchers have suggested that intentional, goal-directed processes formed on the basis of
an experimenter's instructions interact with automatic, involuntary response tendencies to produce goal-directed
behavior. For example, Goschke has presented a number of empirical findings that suggest switch costs are
influenced by intentional processes (e.g., active preparatory processes) and proposes that "intentions modulate
or 'configure' automatic processes for voluntary action, whereas the selection of responses, though dependent on
prior intentions, is influenced by various forms of involuntary processing" (p. 350).
In a similar vein, Hommel (2000, pp. 266) suggested that response selection occurs automatically once a goal
has been set: "Once a task set is implemented (and automatic routes enabled) ... the whole system is prepared to
act in an automatic fashion and this may sometimes produce undesirable side effects." Despite these unwanted
side effects, intentions usually accomplish their goal, so Hommel (p. 267) concluded on a positive note, stating
that "with sufficient time, no subject in a Stroop task would ever name the color word."
Switch costs and involuntary side effects are also characteristic of preschoolers' performance on the DCCS. In
this sense, Kirkham et al. (in press) are correct in drawing parallels between adults' performance on task
switching and preschoolers' performance on the DCCS. However, the qualitative difference between these cases
is that children, unlike adults, do not give the correct response, even when given sufficient time. Even though
preschoolers are not subjected to any time constraints in the DCCS, they fail to sort the postswitch cards
correctly.
What differs between children and adults is the ability to form more complex intentional representations (Frye
& Zelazo, 2003). Three-year-old children adopt the correct goal representation and select the appropriate rules
for acting when doing so does not require them to bridge major branches in a tree structure like that in Figure 3.
For example, 3- to 4-yearolds can switch flexibly between lower order rules during the preswitch phase of the
DCCS (e.g., they first sort a red card and then sort a green card). Three-year-olds fail to switch, however, when
the instructions call for the use of a higher order rule to select a setting condition. CCC theory suggests that
there are age-related improvements in the complexity and scope of children's intentional, top-down processes.
With the construction of higher order rule systems, children's intentional representations become more complex.
These intentional representations structure children's reasoning and behavior, and affect what kind of meaning
children will make of a situation (Overton, 1994, 1998, 2003).
One implication of this intentionalistic approach to executive function is that the representation of a problem is
necessarily subjective, and differs with developmental level. Which stimuli are relevant and what they mean is
determined by a motivated agent in a particular context. The relevant context, in turn, is also subjectively
defined. Constraints on complexity such as those identified by CCC theory operate on rules formulated in an ad
hoc fashion in response to particular problems and always in light of children's own goals. Rules can be
characterized objectively in the context of a well-defined paradigm such as the DCCS, but the rule systems that
children formulate and use in their everyday behavior will be much more difficult to interpret. And as Deak