Abstract

A total of 143 children (3-10 years) completed a saccade stop signal / countermanding saccade task in which a cartoon bee (target) moved to the left or right on each trial. In an Instructed condition, children were told to “follow busy bee” when a green flower appeared at fixation, but “when the flower turned red” to “look straight ahead instead”. In an Uninstructed condition, the stop signal (red flower) still appeared on 25% of trials, but children were told to “ignore the flowers and follow busy bee”.
Surprisingly, children as young as 3 years successfully inhibited target elicited saccades on 40% of stop signal trials. In the Uninstructed condition, older children (>6 years) followed the bee on close to 100% of trials, but younger children still withheld responses on 40% of “stop” trials, even though there was no explicit instruction to do so. Analysis of reaction time distributions indicated that the stop signal exerted an exogenous inhibitory effect on saccades in young children, whereas older children were better at optimising the timing of their saccades. The findings cannot be easily explained by models of saccade inhibitory control which rely on competing Go and Stop control process.