[A researcher shares the secrets of psychophysiological research into players' mental states, outlining several possible techniques and both the pitfalls and potential data that can be gained from applying these in a game test environment.]
As game research and testing develops, there has been an increasing interest different methodologies for assessing games and gameplay. One such area is the use of psychophysiological measures, such as heart rate or electrodermal activity, to assess players' engagement and emotional response.
This article will discuss several of the main measures currently widely used in psychophysiology and their advantages and disadvantages as well as a general discussion of the usefulness of psychophysiological measures.
Psychophysiology is a method for studying the signals provided by the body in an attempt to gain insight and understanding into what psychological processes are underlying or related to those body signals.
In other words. it is using the human body to answer the question "Whatcha thinkin'?" In particular for game research and testing, it can be useful for assessing emotion and mental workload.
Also, since psychophysiology offers game testers and researchers access to data from players without having to go through subjective channels, such as those provided by questionnaires, it also offers a somewhat unbiased assessment of player reactions.
However, since psychophysiology signals do often require quite a bit of interpretation, there is still plenty of room for observation (interpretation) bias on the game tester or researchers' behalf.
One big advantage that psychophysiological measures do have is that they offer access to emotions and body signals that players themselves may be unaware of, and what's more, they can be recorded automatically and continuously without stopping or pausing gameplay.
Before getting into the specifics of the most popular psychological measurements, it is important to quickly cover some basic biological ground. First of all, psychophysiology relies on a view of cognition that asserts human cognition as arising from the whole body. This is called "embodied cognition", and compared to alternate views of cognition, does not propose some kind of separate "mind" where thinking and feeling occurs. Embodied cognition, rather, assumes that our cognitions and feelings arise from a wide system of bodily reactions, and are not simply confined to our brain, for example.
In other words, our cognition is affected by, reflected in, and in fact arises out of our whole body. Now, to use psychophysiological methods you do not necessarily have to buy into this view of embodied cognition, but it is necessary to understand that this is the assumption from which psychophysiology hangs.
Given a view of cognition as embodied, it is important that the body has a good way to communicate, manage and maintain itself. This is handled through the nervous system, which can be split into two parts; the first is the central nervous system, made up of the brain and the very top of the spine. This is the executive control system of the body. As such it is well-protected, and quite difficult to access if you want to measure what is going on in there.
The CNS is much easier to access if you are a demigod.
The other part of the nervous system, the peripheral nervous system, comes out from the spine and handles the day-to-day running of the rest of the body. This means it is much easier for us to access and get measurements of, and it is with this system that most widely-used psychophysiological measures interact. The peripheral nervous system is in turn split into two parts: the parasympathetic system, which handles the general maintenance of the body and relaxation, and the sympathetic system, which is more for handling emergency reactions and excitement.
This means that the peripheral nervous system can be used to measure emotion. In particular, given the typical two-dimension view of emotion, it is particularly useful for measuring Arousal (High, generally sympathetic activity versus Low, generally parasympathetic activity) but is less useful when it comes to Valence (Pleasant emotions versus Unpleasant emotions).
The familiar two-dimension view of emotion.
As an aside, it is worth noting that there is a growing body of evidence in psychology that has lead to a view of feelings and emotions as two different things, despite their generally interchangeable use in everyday language.
This view states that emotions are the body states we have that psychophysiology can detect, for example an increased heart rate meaning excitement, whereas feelings are the conscious perception of the emotional states. That is to say, feelings are when you feel an emotion. The upshot of this is that it may be possible to have an emotion, but not feel it -- yet still have it affect your behavior in some way.
Or to put it in terms of game testing, a player's emotion can be measured through the heart rate monitor, but only when you provide them with a questionnaire (or another subjective measure) can you be sure that you are tapping what that player feels. As mentioned earlier, this means that you may be able to get information from psychophysiology that players themselves do not necessarily consciously have access to.