Do children need reminders on the Day-Night task, or simply some way to prevent them from responding too quickly?

We previously reported better performance on the Day-Night task when a ditty was chanted between stimulus presentation and when children could respond (Diamond, Kirkham, & Amso, 2002). Here we investigated competing hypotheses about why the ditty helps. Does it help because it imposes a brief waiting time (the child waits while the ditty is chanted before responding)? Or, does the ditty help because of its content, providing information helpful to performing the task? One-third of the 72 children (age 4) were tested with the ditty previously used which reminds them: "Think about the answer; don't tell me." Another 24 children were tested with a ditty with no task-relevant content: "I hope you have a nice time; I like you." One-third received the standard condition. Performance in both ditty conditions was comparable and better than in the standard condition. That indicates that a factor common to both ditties (that chanting them took time, allowing the prepotent response to subside and the more-considered answer to reach response threshold) likely accounts for their benefit. Whether a ditty reminded children what to do or not did not affect the results. The challenge of the Day-Night task for preschoolers is not its working memory demands but the need to inhibit a dominant response, making a different response instead.