Workload assessment for mental arithmetic tasks using the task-evoked pupillary response

Abstract

Pupillometry is a promising method for assessing mental workload and could be helpful in the optimization of systems that involve human-computer interaction. The present study focuses on replicating the studies by Ahern (1978) and Klingner (2010), which found that for three levels of difficulty of mental multiplications, the more difficult multiplications yielded larger dilations of the pupil. Using a remote eye tracker, our research expands upon these two previous studies by statistically testing for each 1.5 s interval of the calculation period (1) the mean absolute pupil diameter (MPD), (2) the mean pupil diameter change (MPDC) with respect to the pupil diameter during the pre-stimulus accommodation period, and (3) the mean pupil diameter change rate (MPDCR). An additional novelty of our research is that we compared the pupil diameter measure with a self-report measure of workload, the NASA Task Load Index (NASA-TLX), and with the mean blink rate (MBR). The results showed that the findings of Ahern and Klingner were replicated, and that the MPD and MPDC discriminated just as well between the lowest and highest difficulty levels as did the NASA-TLX. The MBR, on the other hand, did not interpretably differentiate between the difficulty levels. Moderate to strong correlations were found between the MPDC and the proportion of incorrect responses, indicating that the MPDC was higher for participants with a poorer performance. For practical applications, validity could be improved by combining pupillometry with other physiological techniques.PeerJ PrePrints | https://dx.doi.org/10.7287/peerj.preprints.1105v2 | CC-BY 4.0 Open Access |

Ergonomic Assessment of the Mental Workload Confronted by Surgeons during Laparoscopic Surgery

“…14 Previous studies have also reported that the frequency of long fixation is associated with high mental workload, whereas FTR is not. 27,28 Gerhard and Joost investigated changes in eye movement patterns associated with different tasks and contexts involving mental arithmetic, 12 revealing that pupil diameter measurements change according to the level of task difficulty, and that such measurements are as valid as NASA-TLX scores. Zheng et al conducted a study similar to ours regarding the mental workload of surgeons, 8 establishing a connection between task difficulty and pupillary response.…”

“…11 Similarly, significant differences in pupil metrics are observed among various levels of difficulty during mental arithmetic tasks, although no differences in blinking were observed. 12 We hypothesized that different tasks would be associated with different levels of workload, and that this difference would be reflected in detectable physiological differences. The present study aimed to evaluate the mental workload imposed on surgeons during laparoscopic surgery via physiological (eye movement) and subjective [National Aeronautics and Space Administration Task Load Index (NASA-TLX)] analysis.…”

Influence of Increasing Task Complexity and Use of Informational Assistance Systems on Mental Workload

“…This study will focus on the most important indicators: pupillary response (PR), fixation duration (FD), and saccadic peak velocity (SPV) (for an overview, see [ 43 ]). With increasing cognitive or emotional load, pupil size (measured as PR) will increase [ 46 , 47 , 48 , 49 ]. Normal eye movements are a consecutive sequence of fixations and short volatile saccades.…”

Cognitive task analysis and workload classification

“…Cognitive workload is a latent construct that describes the effort required by the working memory to perform a cognitive task [2] . Workload can be measured in many ways, including self-reporting [3 , 4] , performance measures (accuracy and timing of tasks) [5 , 6] , behavioral observations [7] , and neurophysiological measures such as pupil response [8 , 9] , heart rate variability [10] , EEG [11 , 12] , and core temperature [13] .…”