The effect of predictive solutions on training time (speed) and subsequent performance in a complex manual control system was investigated. A control system with a slow and complex response to the input signals was formulated. Fifty control operators, 25 with the aid of predictive solutions and 25 without, were tested; the mean performances of the two groups were compared. There was a definite improvement in training time, directly proportional to system complexity, when the predictive solutions were provided. Posttraining performance doubled when the solutions were available to the operators. Performance without such help remained inconsistent even after a steady state (average or consistent) performance had been reached. (The report includes flow charts, symbols and abbreviations, 13 tables and figures, and seven references.) (Author/LY)