Emotive responses to naturally occurring auditory stimuli: EEG bases in lateralized function, physiological and behavioral self-report

As an individual navigates through their environment, they are presented with a number of different auditory stimuli, which can affect emotions. These emotions are important as they have implications across physiological, behavioral and cognitive domains. This study examined emotions in response to naturally occurring auditory stimuli ranging from neutral, to negative or positive. During the presentation of these sounds, physiological changes were acquired to observe pulse rate and skin potential responses, which view the sweat gland activity to measure changes to the autonomic nervous system. Cognitive measures were taken using an electroencephalogram (EEG) to determine left and right hemispherical changes from the brain potentials. Self-reported measures looked at the differences in emotional valance, from highly pleasant to highly unpleasant, and arousal, from strongly elicited emotion to weakly elicited emotion, for each sound presented. Throughout a 30 minute time period, 60 sound stimuli, selected from the International Affective Digitized Sounds (IADS), were presented to the participant. After the sound presentation self-reported affective valance and arousal was measured using the Self-Assessment Manikin (SAM), a nine-point likert scale. Visceral measures of skin potential responses, pulse rate and brain potentials from the left and right hemispheres were taken before, during and after the presentation of the stimuli. The results of the study indicated that these physiological and behavioral domains were modulated by the affective valance of the sounds. Electrical brain potentials were also related to the types of sounds being presented. The unpleasant sounds were found to elicit the greatest response in each of the physiological measures. The results of this study supported the biological significance of emotions as prescribed by dimensional theorist. The practical and theoretical implications of the results are discussed in terms of the link between emotions and psychophysiology