Goal neglect is a failure to enact task requirements despite being able to accurately report them.In this study, we introduce a new child-appropriate experimental paradigm to measure goal neglect in children between the ages of 7 and 11, and test the hypothesis that the complexity of an action plan, not real-time trial demands, increases goal neglect. Sixty-six children (M age = 9.50) were administered a Feature Matching task. Half were given four rules for matching, and half three rules. After practice, the four-rule group was told to ignore the additional rule, and both groups completed an identical three-rule task. The results showed that the extra rule increased goal neglect and its correlation with fluid intelligence. While intermittent trial errors were correlated with fluid intelligence for both groups, only in the four-rule group were systematic rule failures (i.e., goal neglect) correlated with fluid intelligence. Task performance improved with chronological age, however when controlling for the influence of fluid intelligence, the relationship between age and task performance was effectively removed. This suggests a child's current level of fluid intelligence (and not age) determines task performance.We suggest that the relationship between goal neglect, complex task instructions, and fluid intelligence is linked to the mental preparation for future events; i.e., mentally compiling verbal instructions into a set of activated goal representations in working memory that represent what is to be done and under what circumstances.