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 |

The effects of time pressure on driver performance and physiological activity: A driving simulator study

“…Although the effects for the different physiological measures were mostly similar to each other and in the expected direction, each of these measures has unique strengths and weaknesses. For example, consistent with previous research in memory tasks and arithmetic tasks (e.g., Beatty, 1982;Klingner, 2010;Marquart & De Winter, 2015), pupil diameter has the advantage that it responds within a few tenths of second to changes in task demands, and that it can reach a peak dilation of 0.5 mm in as little as 1 s. It should be noted, however, that fluctuations in pupil diameter might be confounded by environmental lighting and gaze direction (e.g., Beatty, 1982;Klingner, 2010). The heart rate has lower temporal sensitivity, and therefore is less suitable for assessing the effect of scenarios.…”

“…Their findings showed that participants, regardless of their level of driving experience, narrowed their gaze distribution when the driving speed was increased. Recently, remote eye trackers have shown to be promising tools for measuring the pupil dilation response as a function of cognitive task demands in low-cost measurement setups (Klingner, Kumar, & Hanrahan, 2008;Marquart & De Winter, 2015) as well as in driving simulators (Palinko, Kun, Shyrokov, & Heeman, 2010).…”

EEG and pupillometric signatures of working memory overload

“…The human pupil dilates during effortful cognitive activities such as those that require increasing of deployed attentional control resources (Chen & Epps, 2014; Kursawe & Zimmer, 2015; Laeng et al, 2011; Lisi et al, 2015; Marquart & de Winter, 2015; Meghanathan et al, 2014). For example, maintaining information in working memory (WM) is accompanied by subjectively noticeable cognitive effort, and an increase in memory set size and cognitive effort is associated with pupil dilation during WM tasks (Heitz et al, 2007; Kahneman & Beatty, 1966; Karatekin et al, 2004; Klingner et al, 2011; Unsworth & Robison, 2015).…”

Correlative Evaluation of Mental and Physical Workload of Laparoscopic Surgeons Based on Surface Electromyography and Eye-tracking Signals

“…Pupil dilation can be used as a peripheral indicator of brain noradrenergic activity and mental workload in a testing situation. The measurement of pupil diameter has been deemed a promising method for assessing mental workload 38 , 43 , 44 . Task-evoked pupillary responses (TEPRs) have been suggested for exploring the inherent relationship between a task and pupillary dilation 44 .…”