Self-representation in mediated environments: the experience of emotions modulated by auditory-vibrotactile heartbeat

In 1890, William James hypothesized that emotions are our perception of physiological changes. Many different theories of emotion have emerged since then, but it has been demonstrated that a specifically induced physiological state can influence an individual's emotional responses to stimuli. In the present study, auditory and/or vibrotactile heartbeat stimuli were presented to participants (N = 24), and the stimuli's effect on participants' physiological state and subsequent emotional attitude to affective pictures was measured. In particular, we aimed to investigate the effect of the perceived distance to stimuli on emotional experience. Distant versus close sound reproduction conditions (loudspeakers vs. headphones) were used to identify whether an "embodied" experience can occur in which participants would associate the external heartbeat sound with their own. Vibrotactile stimulation of an experimental chair and footrest was added to magnify the experience. Participants' peripheral heartbeat signals, self-reported valence (pleasantness) and arousal (activation) ratings for the pictures, and memory performance scores were collected. Heartbeat sounds significantly affected participants' heartbeat, the emotional judgments of pictures, and their recall. The effect of distance to stimuli was observed in the significant interaction between the spatial location of the heartbeat sound and the vibrotactile stimulation, which was mainly caused by the auditory-vibrotactile interaction in the loudspeakers condition. This interaction might suggest that vibrations transform the far sound condition (sound via loudspeakers) in a close-stimulation condition and support the hypothesis that close sounds are more affective than distant ones. These findings have implications for the design and evaluation of mediated environments.