The effects of different types of feedback in computer assisted instruction were studied in 30 college students with different cognitive styles. The program, written in Apple Pilot and administered on an Apple IIE microcomputer, consisted of 16 problem solving tasks; for each, a graphic display and a textual question were presented. Two feedback treatments were used: knowledge of results--whether the response was correct or incorrect; and information--an explanation of the errors and strategies for correcting them. Cognitive styles, the moderator variables, were field dependence-independence and conceptual tempo (reflectivity-impulsivity). Four measures of performance were used as dependent variables: response time, error rate, number of attempts on each item, and number correct score. The results indicated that field dependent subjects had faster response times and fewer response errors when given an explanation of their errors and strategies for correcting them. Field independent subjects had lower response rates and fewer errors when given only an indication that an error had been made. Age and sex had minor effects on response time for some items. Conclusions regarding the design of feedback in courseware materials are included. (GDC)