  Recent research in the enteric nervous system, sometimes called the second
brain, has revealed potential of the digestive system in predicting emotion.
Even though people regularly experience changes in their gastrointestinal (GI)
tract which influence their mood and behavior multiple times per day, robust
measurements and wearable devices are not quite developed for such phenomena.
However, other manifestations of the autonomic nervous system such as
electrodermal activity, heart rate, and facial muscle movement have been
extensively used as measures of emotions or in biofeedback applications, while
neglecting the gut. We expose electrogastrography (EGG), i.e., recordings of
the myoelectric activity of the GI tract, as a possible measure for inferring
human emotions. In this paper, we also wish to bring into light some
fundamental questions about emotions, which are often taken for granted in the
field of Human Computer Interaction, but are still a great debate in the fields
of cognitive neuroscience and psychology.
