User Experience and Scientific Methods, Part 2: Electroencephalography

What Is Emotional Engagement?

However, the fundamental issue here is not with the technology. It is in the way in which we pin down exactly what emotional engagement is. For example, is it possible for a person to become engaged with something, but at the same time find it repulsive?

Some emotions are much easier to recognize than others. Easy-to-measure emotions are normally polarized to either extreme—positive or negative—such as happiness or disgust. Nevertheless, EEG is not strong enough to definitively attribute an emotion to a specific brain area. EEG is better at registering the intensity of brain signals and emotions rather than recognizing specific emotions.

Because of the complex nature of emotions, scientists have tried using EEG to categorize forms of engagement by tracking the parts of the brain that people employ for the activation and inhibition of emotions. This has helped them to recognize whether someone is engaging with something. In the previously mentioned review of EEG studies, there was conflicting evidence across studies, meaning that they could not establish whether it is possible to definitively measure engagement with EEG. Some people showed engagement where others showed activation.

Being Engaged, but Not Emotional—or Emotional, but Not Engaged

The parts of the brain that are responsible for emotions and activation or avoidance are situated in different areas of the brain. Because we cannot distinguish the nature of the emotions a person is experiencing with an EEG, but only the strength of the emotions, it’s difficult to interpret EEG data. A person could, in theory, feel very angry toward something, but want to engage with it—perhaps to hit it.

A negative emotion does not necessarily mean avoidance. Therefore, a person can engage with something, but not really feel positively toward it. When testing a Web site’s usability, the chances of creating feelings of disgust or intense pleasure are low. So the ability to measure definite emotional engagement is even more limited.

The real question is: can a Web site convincingly evoke that much of an emotional reaction? Could it be consistent? And if it could, wouldn’t that emotional reaction be obvious? In all likelihood, that emotion would be plastered all over the participant’s face—or better yet, would come out through discourse under the direction of the test session’s facilitator. What, therefore, would be the added value of EEG in user research?

What Value Does EEG Add to User Research?

In a scientific setting, the procedure for establishing an effect or causal link requires ruling out as many variances as possible. Web sites present the polar opposite of this situation. They are filled with hundreds, even thousands of cues. All of them are in conflict, so we can’t be entirely sure what is causing a reaction or what information a participant is interpreting.

Even when providing a stimulus that is really basic, with all extraneous biases removed, and testing with an EEG repeatedly, scientists have been unable to consistently establish what will cause a specific part of the brain to show engagement or avoidance or when.

Even if we could establish whether someone is engaged with a stimulus through EEG, their engagement would not be a binary yes or no. Engagement is a continuum. And it’s more likely that, if an EEG does pick up a response, it’s going to be an extreme one. So people whose reactions are slight could look as if they’re experiencing no engagement at all.

In reality, given the complexity of trying to read emotions through EEG and the limitations of the technology, EEG is actually more likely to detect differences in the strength of a person’s reactions to something that he is processing rather than recognizing what the specific reaction is or whether he is engaged with it.

But despite all of this, people are still actively using EEG in user research and branding studies. The device itself—like eyetracking—is designed to work in a context-free environment. A scientist would use it as a way of refuting tiny details and changes to establish a link between something we see and the way our brain reacts. Ultimately, that is not achievable within the environment in which we test. And it is unlikely that EEG could offer us any more answers beyond this discussion. Even worse, it’s possible for the results from an EEG to be misconstrued. So, if the researcher’s definition of engagement is wrong, there are more likely to be false claims of emotional engagement.

It’s important to recognize that there are fundamental limitations with the technology, and the applications of EEG are limited within user research. The very definition of what qualifies as emotional engagement is not standardized. If the scientific community can’t agree on whether the technology can truly recognize emotional engagement, is it ethical for researchers to pretend that it can?