Phasic Electrodermal Activity Indicates Changes in Workload and Affective States

Moderate level of stress is essential to drive an individual towards a specific goal. However, there is growing in prevalence of stress-related illnesses, cognitive and emotional disturbances in developing nations due to increasing task complexity (workload) and disturbances in daily life. Electrodermal activity (EDA) is a non-invasive peripheral index of the sympathetic nervous system that is widely used in psychophysiological studies. Typical EDA data undermined the phasic features that indicates skin conductance responses (SCR) towards stimuli. Here, we attempt deconvolution method to uncover the phasic activity and seek to answer if such features could help us unravel the interacting effects between affective distraction and workload stress. EDA findings showed that participants under the experimental group had heightened SCR when exposed to negative affective stimuli but reduced during cognitive tasks, as compared to neutral control. Although behavioral performance does not reveal significant group differences, negative affective group showed a significant lower SCR expressed by area under curve (AUC) of phasic EDA as compared to neutral control during the highest workload condition (3-back task). We postulate that significant lowered SCR and slight improved performance (accuracy) among negative affective group could indicate intense focus on the most challenging task. Our pilot study shows that phasic EDA is useful to indicate changes in internal states during high workload condition.