Characteristics of the distributions of electroencephalographic (EEG) half waves recorded in children during performance of a simple auditory reaction time (RT) task were investigated. The purpose was to determine the extent to which difference in these distributions could account for children's slow RT. The durations of a sample of 760 EEG half waves in each of a group of 41 healthy children aged 5–17 yr were measured and distributed into an interval histogram, and the first four central moments of the 41 distributions were computed. All four of the moments — which measure the central tendency, dispersion, skewness and kurtosis of the distributions — proved to be significantly correlated ( p < 0.01) with RT. The multiple correlation ( R) between RT and the four moments was equal to 0.68 and was statistically significant. R was unchanged when only the measures of dispersion, skewness and kurtosis were used as predictor variables, suggesting that the predictive value of the central tendency is low. The predictive capability of a multiple regression equation based on these three predictor variables was tested in an independent group of 42 children also aged 5–17 yr. EEGs and RTs were recorded and this group was treated in exactly the same way as the other group. The correlation between these children's average RTs and their RTs as estimated from the other group's regression equation was 0.53. These findings suggested that knowing the degree of dispersion, skewness and kurtosis of the children's EEG distributions reduces from chance by about 28 % the error of predicting their RTs.