An Evaluation of the Usefulness of Four Secondary Tasks in Assessing the Effect of a Lag in Simulated Aircraft Dynamics

Kight male subjects were required to perform a tracking task using an electronic windshield display. The task had two levels of difficulty, an essentially unlagged condition and a condition, chosen to be perceptibly more difficult, having an exponential lag of 0-5 sec. Integrated tracking error scores alone were unable to distinguish between the two difficulty levels. Four secondary tasks were utilized involving a response to digits presented in the forward field of view. The four tasks were arranged to be of comparable difficulty level in pretests using the same subjects. Two secondary tasks indicated a difference between the primary task conditions. The addition of a secondary task also permitted tracking error scores themselves to indicate a difference.