Quantitative Evaluation of Mental Workload by Using Model of Involuntary Eye Movement

Abstract

Abstract. This study considers a new method to quantify mental workloads (MWL) by using mathematical models for reflex movement of eye. Several mathematical models of reflex movements have been proposed and experimentally verified by physiologists. In those models, some models of vestibuloocular reflex (VOR) have sufficient accuracy to predict eye movements of individuals. The engagement of brain function to VOR is known in the learning process or in the adaptation process. This leads to the assumption that metal workloads appears in the change of characteristics of VOR. So as to confirm the assumption, we have designed an experimental setup and carried out several experiments. In the experiments, subject's VOR responses have be accurately predicted by the mathematical model which is a dynamical model with the input of head movements and the output of eye movements. The model dynamics have changed while the subject was engaging in a higher cognitive activity. The coherence between the predicted VOR from the identified model of the particular subject and the observed VOR was as high as 0.92 when there was no additional mental demands. However, the changing MWL over five different n-back tasks revealed the clear correlation between the predicted VOR coherences and the MWL demands. This shows that MWL can be objectively quantified by measuring the error between observed VOR responses and the predicted VOR ones from the identified model.

Evaluation of Driver Distraction with Changes in Gaze Direction Based on a Vestibulo-Ocular Reflex Model

“…As reported by Obinata et al and others [3] [4] [15] [17], motion sickness has a strong effect on VOR parameters. To identify the optimal VOR parameters for driver distraction, we used the first ten seconds in our distraction-evaluation experiment for parameter identification, and then we applied the identified parameters throughout the remainder of the experiments.…”

“…Obinata and co-workers [3] [4] [11] [12]. The difference between the case with an MWL and that in its absence was clearer than the previous case, in which the average mean-square error for no MWL was 1.56E−03 and that with an MWL was 3.48E−03 (more than two times).…”

“…Obinata's group has also used the VOR model to evaluate mental workload [3] and driver distraction in terms of memory-decision workload [4]. They presented a new method for quantifying mental workloads by utilizing the VOR.…”

“…However, Obinata et al have stated that the horizontal axis has a much narrower range of movements than the vertical axis [3]. Consequently, we only considered movements in vertical direction, which have a strong effect on eye movement.…”

Improved Temporal Resolution Heart Rate Variability Monitoring—Pilot Results of Non-Laboratory Experiments Targeting Future Assessment of Human-Computer Interaction

“…Eye-tracking is a promising direction of further developments of our methodology: (a) it is reliably capable of localizing the user interface elements that cause high mental effort or emotional reactions identified by the other physiological channels by synchronizing the channels, and (b) it can be analyzed deeper, deriving parameters referring to the state of the nervous system [26].…”