As ships have larger mass and tend to suffer disturbance forces of wind, wave and so on, they are regarded as "time lag system" from the point of view of human operation. The purpose of this study is to investigate man's adaptation to "time lag system" through fundamental experiments and to make clear how a man makes progress to make adaptation to such a time lag system. This research was carried out according to a series of researches involved the last experiments (Shimada, et al., 2003). The experiment was carried out under control of the amount of time lag on cursor motion on CRT through PC as well as the last experiment. On each trial the participants made responses by press key to stop cursor motion at the location of the small red circle (target) on CRT. The distance between the target and the cursor was dependent variable of this experiment. The participants were divided into two groups at random under either condition of fast or slow cursor speed. The participants of each group made 400 trials which include 2 x 2 conditions of time lag (either no or large time lag from key press to response of PC and either good or bad brake efficiency). The participants made more exact responses under no lag than long time lag regardless of brake efficiency or cursor speed. Compared with the last experiment (2003), time lag got modified as no or 15 second. Two kinds of cursor speed (half and same as the last experiment) were introduced. This experiment made more complicate schema than we assumed on human adaptation to "time lag system". Fast cursor did not produce accurate responses and encourage learning on time lag system as well as slow cursor did not. Middle speed cursor produced most inaccurate responses and difficulty of learning on time lag system. Two time lags (15 and 2.6 second) made similar effects on learning on time lag system in the same condition of cursor speed as the last experiment. In this condition, the participants needed more than 90 trials to arrive at the level of accuracy in the other condition. This research needed introduction of large time lag (above 30 second) into the experiments in the next step. We continue to investigate process of learning on time lag in detail.
