THE DEVELOPMENT OF EXECUTIVE FUNCTION IN EARLY ...

Negative priming in children has also been explored in Piagetian conservation tasks by Houde and Guichart
(2001; see also Perret, Paour, & Blaye, 2003). Piagetian conservation involves the understanding that a
change in the appearance of an object or group of objects (e.g., the length of a row of objects) does not
necessarily signal a change in the quantitative value of the object or group (e.g., the number of objects in that
row). Houde and Guichart had 9-year-olds judge the numerical equivalence of two rows of shapes when the
use of a primed Piagetian length-equals-number strategy was either congruent or incongruent with the correct
response. The authors found that children who were required to ignore the strategy that length is indicative of
number subsequently took longer to use that strategy when it was required for the correct response.
Perner and Lang (2002) discussed the possibility that negative priming (in the sense of persistent inhibition)
may occur in the DCCS. That is, sorting by the preswitch rules may require children to inhibit the irrelevant pair
of rules, and this inhibition may persist or be reinstated in the postswitch trials, decreasing the probability that
these rules will be selected in the future (i.e., during the postswitch phase, when they become relevant).
Negative priming in this sense may also explain results they obtained with modified versions of the DCCS.
These authors found that when the target cards varied on only one dimension or when no target cards were used
at all, 3- to 4-year-olds' performance improved. In both cases, they suggest, there was no need to inhibit the
irrelevant rules during the preswitch phase. However, their results are also consistent with other hypotheses. For
example, the lack of target cards could have made the preswitch rules less salient and therefore easier to forget
when the rules changed (Perner & Lang, 2002, p. 101). Consequently, children may not have needed to
construct a higher order rule to switch between rule pairs; they may simply have sorted according to two rule
pairs in succession, without coordinating them.
Although it is possible that negative priming contributes to children's difficulty on the DCCS, it cannot account
for this difficulty completely. If negative priming alone were operative in the DCCS, then children should have
performed well on the Partial Change version in Experiment 7, in which the values of the dimension that was
irrelevant during the preswitch phase were replaced by new values. Because these values were replaced,
performance on this version cannot reflect negative priming, only persistent activation of the preswitch rules (or
some other process).
Curiously, although negative priming may be a problem that children need to overcome (Perner & Lang, 2002),
it is usually conceptualized as evidence of a developing ability that allows successful selective attention (e.g.,
Dempster, 1995; Houde & Guichart, 2001; Tipper et al., 1989). For this reason, the negative priming hypothesis
is incompatible with inhibition accounts such as that proposed by Kirkham and colleagues (in press). Whereas
inhibition accounts suggest that children fail to inhibit during the postswitch phase, the negative priming
hypothesis suggests that children fail to disinhibit during this phase. Put differently, inhibition accounts suggest
that children perform poorly on the DCCS because of too little inhibition, whereas the negative priming
hypothesis suggests that children perform poorly because of too much inhibition. Perhaps for this reason,
Kirkham et al. explicitly state that negative priming would not occur in the DCCS. They write that "children
should be able to succeed if the previously-relevant values on the now irrelevant dimension are no longer
present in the stimuli (and they do)" (p. 5). To our knowledge, however, this claim has not actually been tested.
Experiment 8 was designed to test directly the role of negative priming in relation to other possible sources of
difficulty on the DCCS. Children were given one of six versions of the DCCS: the standard version, the Total
Change version, the Partial Change version, and three new versions (see Figure 16). In the Negative Priming
version, the values of the dimension that was relevant during the preswitch phase were removed during the
postswitch phase. This version should provide a pure measure of negative priming (vs. persistent activation of
the preswitch rules) because performance on the postswitch phase would be sensitive to negative priming, but
not to persistent activation.
In the Partial-Partial Change (test cards) version, the values of the irrelevant dimension during the preswitch
phase were removed from the test cards during the preswitch phase. For example, as shown in Figure 16, when
the preswitch sorting dimension was color and target cards included a blue rabbit and a red boat, test cards were