A New Method for Evaluating Mental Work Load In n-Back Tasks

Abstract

It is important to evaluate mental work load on drivers will be useful for managing operator’s work load or for preventing from overloaded tasks. However, there does not exist any quantitative method for evaluating mental work load in real time. This motivates the study of proposing a new method to evaluate the influence of mental work load caused by information processing demand. Our method focuses on involuntary eye movement of human, which is vestibulo-ocular reflex (VOR). The eye movement occurs reflexively for gaze stabilization while paying attention to the target. We have investigated the influence of mental work load on VOR using a new model-based method. The first step of the method is to identify the eye movement model for a particular subject from measured data without any secondary task. This model represents the subject’s dynamics of VOR. After that the eye movement is measured when the subject get distracted by paying attention to secondary tasks, and it is compared with the identified model output. This method makes it possible to assay the influence of mental work load on VOR. This study has investigated the influence of mental work load on human eye movement by giving n-back tasks as the secondary task. By varying the amount of information processing demand of n-back tasks, we compare the variations of the dynamics of VOR from the identified model which represents human VOR dynamics in ideal situation. Consequently, we give a proof of quantitatively evaluating mental work load using our proposed model-based method.