Two studies examined the effectiveness of self-instruction training via a specially developed computer program to modify the impulsive problem-solving behavior of 16 deaf and 10 learning disabled (aphasic) adolescents attending two special residential schools in Canada. In the control condition, students learned the Apple LOGO computing language and practiced problem solving on the computer. In the treatment condition, students were given the same exercises, but in addition given self-instruction training using the "REFLECT" computer program which was designed to elicit overt verbalization of thinking behavior and teach reflective problem-solving strategies. Deaf students participated for 12 weeks, aphasic students for 6 weeks. In the study with deaf students, group comparisons of dependent measures showed significant improvement in the treatment group on errors, global measures of impulsivity, and errors on the Matching Familiar Figures Test. An ordinal aptitude x treatment interaction was noted as was a trend toward transfer as measured by the self-control rating scale. In the shorter study with aphasic students, there was significant improvement in judges' evaluations of global characteristics of impulsivity. Other measures suggested the treatment group became more effective with the LOGO language than the control group. (DB)