This position paper describes an experiment conducted to understand the relationships between different physiological measures including pupil Diameter, Blinking Rate, Heart Rate, and Heart Rate Variability in order to develop an estimation of users' mental load in real-time (see Sidebar 1). Our experiment involved performing a task to spot a correct or an incorrect word or sentence with different difficulties in order to induce mental load. We briefly present the analysis of task performance and response time for the items of the experiment task.
In relation to our long-term goal, we currently find empirical evidence that few of the physiological behaviours are correlated with each other. For instance, both pupil dilation and blink-eye rate were seen to be correlating with each other in a digit-sorting task @cite_5 . However, to the best of our knowledge, the relationship between all these behaviours have not been explored and is necessary to efficiently create an estimation for cognitive load or mental load. As highlighted we need to understand the relationships between different behaviours because this can help in creating a linear mixed-effect regression model that may estimate mental load in real-time during HCI or HRI. Consequently, We, in this paper, presents intial finding of a study conducted in order to collect data on these behaviours in a synchronous way to help us analyze the relationships between different physiological behaviours and later create a dataset that can be used to estimate cognitive load in real-time.
@cite_5
2154200694
Pupil dilation and blinks provide complementary, mutually exclusive indices of information processing. Though each index is associated with cognitive load, the occurrence of a blink precludes the measurement of pupil diameter. These indices have generally been assessed in independent literatures. We examine the extent to which these measures are related on two cognitive tasks using a novel method that quantifies the proportion of trials on which blinks occur at each sample acquired during the trial. This measure allows cross-correlation of continuous pupil-dilation and blink waveforms. Results indicate that blinks occur during early sensory processing and following sustained information processing. Pupil dilation better reflects sustained information processing. Together these indices provide a rich picture of the time course of information processing, from early reactivity through sustained cognition, and after stimulusrelated cognition ends. Descriptors: Blinks, Pupil dilation, Cognitive load, Attention, Stroop