Pupil diameter dynamics as an indicator of the respondent’s cognitive load: Methodological experiment comparing CASI and P&PSI

In recent years, the increase in general interest in methods for measuring cognitive load and subjectively perceived mental effort when solving various tasks and in the interpersonal communication was accompanied by an increase in the specific interest of social researchers in the multimodal assessment of the cognitive load of interviewers and respondents based on objective and subjective indicators, including paradata and webcam data, in order to control this load’s impact on the quality of survey data. The authors argue that the possibilities of relatively new approaches to measuring cognitive load with neurophysiological methods (such as the use of wearable devices for oculography - eye tracking and pupillometry - which do not disrupt the natural course of respondents and interviewers activity) are still underestimated, although they allow an accurate time linkage of measured parameters’ dynamics (primarily the size of the pupil) to the question format, mode and phase of survey completion, external influences localized in time, etc. As a rule, quantitative studies of surveys’ cognitive load and its possible impact on the quality of survey data focus on computer-assisted (CAPI) or paper-based (PAPI) interviewing, while the specificity of the cognitive load in the self-completed computerized (CASI) and paper (P&PSI) surveys was not studied. The article presents the results of the methodological experiment based on a modified version of the multimodal approach to the comparative assessment of the cognitive load of interviewers working with paper and computerized questionnaire. We expanded the range of methods for assessing cognitive load by using a wearable oculographic device (eye tracker) to measure the dynamics of pupil size when answering different survey questions. The results of the experiment confirmed the hypothesis about the approximate equivalence of the two modes of survey completion in terms of their cognitive load for younger respondents with a high level of functional computer literacy, and allowed an initial assessment of the technical and metrological capabilities and limitations of the use of pupil dynamics’ indicators, measured with a wearable oculographic device, to study the respondents’ cognitive load.