A modified version of the stop signal task (suitable for use with very young children) was administered to a pre primary school group of children (<5 years, 6 months); a young primary group (5 years, 7 months to 7 years, 6 months); a mid primary group (7 years, 7 months to 9 years, 6 months) and a group of adults. Significant age differences in the ability to inhibit responding were found. These results highlight the need for measures of response inhibition which are appropriate for use with very young children, when the first signs of inhibitory skills are emerging. It is also imperative that such measures allow the assessment of skills across a broad range of age groups in order to comprehensively monitor their development.

The stop-signal task, a measure of inhibitory control, was further modified in order to examine its suitability as a task for very young children. A previous study (Carver et al., 2001) showed that it can be successfully adapted for use with primary school-aged children. The present study manipulated the presentation of the signal to inhibit responding and found that this improved the likelihood of responding. A pre-primary school group of children (< 5 years, 6 months), a young primary school group (5 years, 7 months to 7 years, 6 months), and a mid-primary school group (7 years, 7 months to 9 years, 6 months) participated in the study. The results emphasize the pre- and early school years as a sensitive time for the development of inhibitory skills. Measures of inhibitory control must therefore be age-appropriate and sensitive to these early developmental changes.