Assessing the Emotional Reaction to Negative Pictures Through Electrodermal Activity Data

We are constantly exposed to countless visual stimuli that trigger different emotions and reactions in individuals. Assessing one’s own reactions to visual stimuli can be a powerful tool for diagnosing a person’s psychological state, as well as to evaluate, objectively, the effects of one’s interaction with the environment. Currently, the measurement of this emotional responsiveness to visual stimulation is mostly carried out by means of self-reporting questionnaires, which lead to a quite subjective assessment of the emotional impact of the presented stimuli. The aim of this study is to investigate the use of Electrodermal Activity (EDA) to predict the level of emotional response of individuals to negatively charged pictures. With this purpose, we collected EDA signals from 25 participants, while they visualized a sequence of 75 emotional response pictures, from the International Affective Picture System (IAPS). The most relevant EDA parameters, such as amplitude, area, skin conductance levels and the number of specific responses were statistically confronted with the arousal and valence of each image. This analysis showed the expected increase in the first three parameters for high arousal pictures. We also found that more neutral valenced ones had higher amplitude and skin conductance levels than pictures with negative valence. Those results show that the Electrodermal Activity can be used as an objective indicator to evaluate emotional arousal, as a response to viewing negative pictures. In addition, it opens the possibility to use such electrophysiological measurements, in a clinical, social or ludic context and, in such way improve certain forms of diagnosis, as well as assess the efficiency of visual interaction with a particular individual, while allowing for a more objective way to monitor the emotional effects of said interaction.