抄録
Visual-motor reaction time to 6 light signals was measured in case that the probability of each signal was not equal. It proved not to be proportional to the entropy of information sources, and was shorter than reaction time to selective signals of equal probabilities. The judgement period in terms of the difference cf the reaction time and motion time was significantly correlated with the signal probability. It was the larger, the smaller was the display probability of the signal. If 64 red lamps were placed on a panel in forms of 88 cm squares, the judgement period without previous instruction of the lamp positions to be lit was delayed, especially when the entropy of information sources was larger. The relational shortening of the reaction time for unequal signal probabilitiest uneven concentration of attention was discussed.
