Achievement in earning grades in high school was resolved into its intellectual and motivational components. This study employed tests of I.Q., personality inventories and classical and operant conditioning of autonomic nervous system controlled variables. Eleven procedures were given to 99 Black inner city high school seniors. Six physiological variables were analyzed directly on a computer using analog-to-digital conversion and programs which identified and summarized all responses and recoveries to the tones and pain stimuli of the classical conditioning and those during the operant conditioning using analog biofeedback of heart rate. Achievement (ACH) was defined as the residuals of average total grade point average (GPA) regressed on I.Q. Both ACH and GPA were examined as to their components. Results of regression analyses showed that 50.89% of the variance of GPS was accounted for by I.Q. 20.44%, Edwards Personality Inventory 9.08%, operant conditioning 18.70%, and classical conditioning 2.6%. Findings from this study appear to justify the conclusions that for this population of students, the measures of motivation account for 30.45% of the variance whereas I.Q. accounts for only 20.46% of the variance in grades. (Author/MLP)