Detecting emotions during the application of skin conductance and heart rate measurement techniques

Tuna Çakar

Emotions have long been recognized as influential factors in human behavior and they have various influences on motivation, cognition and attention. A variety of empirical evidences have shown that emotions have been a vital component of cognitive processes. Although there is great interest in determining the role of emotions in cognitive processes, the application of physiological emotion measurement by experimental techniques is still limited. This research investigates the emotion through a series of psycho-physics experiments. One aim of this research is to demonstrate its use via an experimental design for investigating the role of emotions in external affection during affective picture viewing. Another aim is to apply the tools for measuring emotions in ways that will make them more accessible to researchers wishing to investigate the emotional determinants of subjective affection. In other words, the purpose of this study is to test the equipment whether it could be used to demonstrate the emotional affection and to characterize type of experienced emotions. These goals have been accomplished by adopting and refining a physiological technique of emotion measurement known as electro-dermal activity and heart rate measurement. Many of the studies involve the use of physiological equipment that is costly and difficult to implement. One of the main features of this research is to use a low-cost instrument for electro-dermal activity (EDA) measurement that has been non-invasive and widely used in psychophysiology as an indicator of emotional arousal. This measurement has been recorded during a sensitive measure of emotion-related sympathetic activity caused by presentation of a novel unexpected stimulus. A significant part of this research involves the implementation of MATLAB software that facilitates data acquisition and analysis. I have superimposed the EDA and HR data series and the list of events, thus, I have performed event-related analysis to examine whether particular stages of the experiment had emotional consequences. This thesis project has been implemented by using facilities available in the laboratory of Biomedical Engineering Faculty in Boğaziçi University. Each subject was presented a series of affective and non-affective pictures during the measurements of electro-dermal activity and heart rate. Subjects were told to think about the presented pictures that were shown for six seconds. Another method, as a complementary to EDA and HR techniques, has been self-assessment manikins (SAM) that has been well-known to be subjective and less accurate than physiological methods. Two methods have shown that emotional arousal and valence can be observed empirically but there are certain limitations in determining the type of affection experienced by the subject. The results of this study demonstrates that these tools can be used as a reliable one in psychophysics research as well as could possibly be used in experimental economics or experimental ethics research. In other words, affective picture demonstration influences the electro-dermal activity as well as heart rate of the subjects that give clue about the emotional arousal and valence of the participants but it is not possible to characterize and categorize the emotion experienced depending on the obtained physiological data.