A hard challenge for wearable systems is to measure differences in emotional valence, i.e. positive and negative affect via physiology. However, the stomach or gastric signal is an unexplored modality that could offer new affective information. We created a wearable device and software to record gastric signals, known as electrogastrography (EGG). An in-laboratory study was conducted to compare EGG with electrodermal activity (EDA) in 33 individuals viewing affective stimuli. We found that negative stimuli attenuate EGG's indicators of parasympathetic activation, or "rest and digest" activity. We compare EGG to the remaining physiological signals and describe implications for affect detection. Further, we introduce how wearable EGG may support future applications in areas as diverse as reducing nausea in virtual reality and helping treat emotion-related eating disorders.

Version: Final published version