Empirical approaches to quantifying effort, fatigue and concentration in the conceptual design process

Recently, physiological signals such as eye-tracking and gesture analysis, galvanic skin response (GSR), electrocardiograms (ECG), and electroencephalograms (EEG) have been used by design researchers to extract significant information to describe the conceptual design process. We study a set of video-based design protocols recorded on subjects performing design tasks on a sketchpad while having their EEG monitored. We propose empirical approaches to quantify effort, fatigue, and concentration during the conceptual design process. To perform this analysis, we extract EEG features that convey information on effort, fatigue, and concentration. We argue that all three are relevant in the conceptual design process. Such an analysis has the merit of being fully automated, readily integrable in engineering systems and not being subjected to the subjectivity of the domain expert performing the analysis like in subjective rating frameworks. Our analysis leads to four hypotheses: (1) effort and fatigue are subjected to ice-breaking and end of task phenomena; (2) fatigue and effort follow a capacity model; (3) fatigue is multidimensional; and (4) concentration follows a modal shift model.