This dissertation, "Impulse Control in Developing Brain" by Miu-ching, Adelina, Lau, 劉妙貞, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Impulsivity is a complex, multifaceted domain with cognitive (level of attention), affective (emotion regulation) and behavioural (reward responsiveness) manifestations. No study had been done so far on trajectory of impulse control, attention and reward responsiveness in child development. The aim of the present study is to compare the level of impulsivity, attention and reward responsiveness among children at different stages of development. Forty Chinese, healthy children (2 male and 17 female) from primary one and primary six were recruited. Subjects were matched for intelligence. Assessment was done individually. Stoop test and Child Behavior Checklist were used to evaluate the impulsivity level of the subjects. Cancellation subtest of Wechsler Intelligence Scale for Children and Sensitivity to Reward and Sensitivity to Punishment Questionnaire- Children version (Cooper & Gomez, 2008) were used to evaluate attention and reward sensitivity of the subjects. The difference in impulsivity between the 2 groups was not statistically significant, while the difference in attention between the 2 groups was statistically significant. Moderating effect of age on the relationship between attention and impulsivity was significant, indicating age could moderate the effect of attention on the development impulsivity. Correlation between sensitivity to reward and impulsivity is statistically significant. Reward responsiveness was a good predictor of ability of impulse control in this study. To conclude, the ability control impulse is affected by multiple factors. Attention problem and reward responsiveness is likely to be predictive of impulsivity. Further research on the influence of sensitivity to reward of children on impulsivity along the developmental trajectory should be considered. DOI: 10.5353/th_b5070025 Subjects: Impulse