Your heart might give away your emotions

Estimating emotional responses to pictures based on heart rate measurements: variations in Heart Rate serves as an important clinical health indicator, but potentially also as a window into cognitive reactions to presented stimuli, as a function of both stimuli, context and previous cognitive state. This study looks at single-trial time domain mean Heart Rate (HR) and frequency domain Heart Rate Variability (HRV) measured while subjects were passively viewing emotionally charged images, comparing short random presentations with grouped sequences of either neutral, highly arousing pleasant or highly arousing unpleasant pictures. Based on only a few users we were not able to demonstrate HRV variations that correlated with randomly presented emotional content due to the inherent noise in the signal. Nor could we reproduce results from earlier studies, which based on averaged values over many subjects, revealed small changes in the mean HR only seconds after presentation of emotional images. However for longer sequences of pleasant and unpleasant images, we found a trend in the mean HR that could correlate with the emotional content of the images. Suggesting a potential for using HR in single user Quantified Self applications to assess fluctuations over longer periods in emotional state, rather than dynamic responses to emotional stimuli.