Inventing a new measurement for inhibitory control in preschoolers.

One of the most prominent tasks to measure spatial-conflict inhibitory control in preschoolers is the windows task (Russell et al., 1991, Br. J. Dev. Psychol., 9, 331). However, this task has been criticized given its high demands on abilities other than inhibition. The aim of the current set of studies was to establish the 'car task' as a novel instrument to assess conflict inhibition in children. In this task, children are asked to point at the current location of an occluded object. To do so, they have to inhibit a misleading colour cue in front of the locations in critical trials. In Study 1, we demonstrated that 3- to 6-year-old children's (N = 88) performance in the car task correlated positively with that in the windows task (even after controlling for age). Study 2 investigated whether children's failure in the car task might be caused by their inability to master the basic processes involved in the task rather than a lack of inhibition. We presented a new group of preschoolers (N = 85) with a modified version of the task without any misleading colour cues. Performance significantly improved, indicating that the difficulty of the car task lies in the necessity to inhibit the misleading colour cue leading towards the incorrect location. These findings suggest that the car task is a valid measurement of spatial-conflict inhibition in children. Statement of contribution What is already known on this subject? Inhibitory control (IC) is important for action planning and execution. One of the most prominent measurements of spatial-conflict IC is the windows task. This task has been criticized for additionally requiring rule inference to succeed. What does this study adds? Performance in the novel car task correlates with that in the windows task. Study 2 controls for demands other than IC such as memory or task difficulty. This task can thus be used to measure IC more purely without demanding rule inference.