Under what conditions do young children have difficulty inhibiting manual actions?

Understanding how responses become prepotent is essential for understanding when inhibitory control is needed in everyday behavior. The authors investigated the conditions under which manual actions became prepotent in a go/no-go task. Children had to open boxes that contained stickers on go trials and leave shut boxes that were empty on no-go trials. In Experiment 1 (n = 40, mean age = 3.6 years), the authors obtained evidence consistent with this task requiring inhibitory control. Results of Experiment 2 (n = 40, mean age = 3.7 years) suggested that box opening was prepotent because (a) opening is the habitual action associated with boxes and (b) children planned to open boxes on go trials of the task. Experiment 3 (n = 96, mean age = 3.5 years) showed that even empty boxes elicited the same errors and that delaying responding reduced errors even though the delay occurred before the cue that indicated the correct response (contrary to a rule reflection account). Because the delay occurred after box presentation, performance was consistent with a transient activation account. Delay training might benefit children with weak inhibition.