SUMMARY. The purpose of the study was to demonstrate that impulsive behaviours and the resulting faulty social problem-solving may be changed by altering clusters of beliefs orienting to these behaviours. The theoretical rationale was provided by the cognitive orientation theory. The hypotheses were that the belief clusters would change through experimental training and that the behaviours would change if the belief clusters change. The subjects were 74 children, about 10 years old of both genders, defined as impulsive by their class tutors. They were tested before and after experimental treatments on the Pre-School Inter-personal Problem-Solving Test, Matching of Familiar Figures and beliefs concerning reflectiveness. In addition, pre-and post-measures on Behavioural Measures of Adjustment and behavioural observations of impulsivity were obtained. The experimental treatment of eight meetings consisted of training the relevant beliefs, or behavioural plans, or both. Control subjects had either eight meetings devoted to games or no meetings. The findings showed that the beliefs were changed as expected, and that in nine of the ten behavioural measures there were changes, provided the beliefs changed. The discussion focused on the implications for the cognitive orientation theory, impulsiveness, and changing of other behaviours.INTRODUCTION THE purpose of the study was to demonstrate that changing specific cognitive contents for children rated as impulsive would bring about a reduction in the level of their impulsiveness. The rationale and methodology for the study are rooted in the theory of cognitive orientation (CO) (Kreitler and Kreitler, 1972a, 1976, which is a general behaviour theory describing how cognitive contents 'and processes guide human molar behaviour. The theory outlines the major phases intervening between the occurrence of some external or internal input and a behavioural act. The input is first subjected to a primary meaning assignment procedure (" meaning action "),