Do more insights equal better results? When neuroscience meets user research…

EEG measures brainwave activity. So, what does this mean? Well, first of all, it doesn't mean that we measure what the subject is thinking! It just measures the electric activity on a very specific point on the scalp. And to do this correctly, you need a lot of data points (electrodes) that correct the various sources of distortion. The insights we gain from this, is knowing in which part of the brain something may be happening. Triangulating EEG with EMG helps identifying physiological artifacts (confounding peaks from body movement)

EMG measures muscle activity. Here again, electrodes measure the electric activity. As the subject's facial and gestural expressions can be detected, it provides us with insights about the inner state & emotions. Additionally, EMG can be used for eye tracking (although it is not as precise as traditional eye trackers).

EDA measures skin conductance. The underlying concept of this is measuring the skin's electric conductance through its moisture level. High moisture levels are usually associated with a high level of arousel, which can be interpreted (depending on the valence) as either stress or excitement.

Costs. I asked the speaker of the presentation how much a test like that would cost. For 20 participants, including conduction & analysis, it would be around 20.000 EUR. Pretty expensive if you ask me... If you would like to do it yourself, proper (medical) equipment would cost you about 100 times as much. Yet, there are also a few low-cost EEG devices on the market (called neuro headsets), with fewer electrodes and lower resolution. Measuring EDA is the cheapest of the three methods mentioned, you just need one finger clip connected to an ohmmeter.
Fun Fact: Scientology uses EDA to "measure" how pure your soul is.

Time. Preparation & conduction is more time-consuming than usual usability tests are. Above that, data analysis is much more sophisticated and will cost you (at least) more than twice the time.

Know-how. You need real experts to analyze and interpret the data properly (which will cost you in the end money again). You would wonder how much the data varies between participants! It is not advised to simply read into the topic, if you are a complete newbie. The only thing worse than no data, is false data.

Stress. Your test subjects have to go through some procedures, which can be quite stressful for them. Electrodes must be placed on the participants' bodies and hair, often by using conductive gel. Let me ask you, would you like to have to wash your hair after a study?

Data Validity. You need to spend some time to "train" and calibrate your machines (e.g. for a proper baseline). There are several confounding factors and error sources that may incluence your raw data, while normalizing and filtering it might change its nature, endangering the validity of your data. Above that, test preparation (remember the sticky electrodes) and conduction (strictly controlled lab setting) pose serious consequences to your data's ecological validity.

EEG data will tell us, which brain regions are probably associated with processing information of a particular game element. Potential bottlenecks could be identified, which then would provide information architects with insights for a redesign or optimization of a specific part of the game. User researchers could use event-related potentials (ERP's) to identify critical game incidents and do further research for its determinants. This knowledge can be passed on to game designers to create user-centered experiences (literally).

EMG can be used to evaluate game sequences for their elicit emotions (although that is very difficult). More easily, emotional dead spots can be identified, telling which parts of the game appear to be boring and which parts of the recorded video might require special attention. Additionally, EMG is of particular interest in researching and designing motion controls. It provides immediate feedback of the users' movement, which can be used as input for designing game-specific ergonomic control methods. Unfortunately, only very few big developers afford to apply R&D.

EDA is the easiest to measure out of the 3 methods mentioned. It can be used to provide indicators for emotional repsonses at a given state of the game. However, emotions cannot be identified, so its application is of complementary nature only.