Abstract
This experiment examined the ability of observers to determine, as quickly as possible, whether a visual indicator was steadily on or flashing. The results show that the observers view the light for an interval of time appropriate to the expected flash rate and duty cycle; whether they judge the light to be steady or intermittent depends upon whether the light is extinguished during the predetermined waiting period. The decision or response criteria held by the observers are also sensitive to the parameters of the flashing light: observers become increasingly willing to call a flashing light "steady" as flash duration increases.