AFFECTIVE COMPUTING
What Causes our Physiological Responses?
Many of our physiological responses are controlled by the autonomic nervous system, ANS. ANS is the system that regulates the functions of our internal organs. This includes, heart rate, breathing rate, digestion etc. ANS will be affected due to different emotions and will prepare the body for certain responses. The ANS is split up into the Parasympathetic and Sympathetic Division. The parasympathetic division is responsible for energy conserving activities such as digestion. Sympathetic division, on the other hand, is in charge of sudden stimuli and intense activities. It can stimulate tissue metabolism, increase heart rate and many other processes controlled by the ANS.
Theories of Emotions
There are numerous theories with different viewpoints on how emotions are related to physiological responses. There are three main theories which are often discussed list here.
Blood Volume Pulse & Skin Conductance
Blood volume pulse and skin conductance are some of the more common identifier of emotions. They are relatively easy to detect compare to other physiological responses and the details of how they are detected will be mentioned here.
Other Physiological Responses
Apart from using BVP and skin conductance, there are several other physiological responses that can be used to detect the affective state of the user. Most of these signals can either be detected with the two mentioned above or are fairly difficult to detect in a natural environment.
Uses & Examples
There are many different devices that uses physiological responses as an indicator of the emotion of the user. These range from the polygraph, which was invented in 1921, to the more recent head gear, the bio-glass from MIT.
Limits & Challenges
Using physiological responses to accurately detect emotional state is still in its very early stage. Although it does give a general idea on how the subject is feeling, it has been proven difficult to measure these responses in a natural environment.