Fourteen children, aged 7–11 years, were selected from an initial sample of 190 to give a range of scores on the JEPI. They were also evaluated by a Teacher's Rating Scale for neuroticism. The children were trained in a discrimination learning task which yielded measures of peak shift, behavioural contrast and stimulus generalization. Peak shift and behavioural contrast were positively correlated. Neuroticism was positively correlated with both one measure of peak shift and stimulus generalization. Extraversion was negatively correlated with a second measure of peak shift and positively correlated with generalization. With increasing developmental maturity (chronological age, reading age and relative advance of reading age), both peak shift and behavioural contrast tended to be reduced.