It’s the same in almost every sci-fi movie. The protagonist is strapped to a chair, kicking and screaming, and subdued just long enough for an array of wires and electrodes to be strapped to his head. Despite his best efforts, the antagonists begin to read his thoughts.
Thankfully, this terrifying depiction is a far cry from the technology that is now par for the course in many neuroscience studies and neuromarketing practices. (In any case, it’s REALLY easy to mess up an EEG reading, so our hero is probably fine!)
What is it?
EEG (electroencephalography to the Spelling Bee winners out there) is the translation of the electrical activity of your brain’s surface onto paper, virtual or otherwise. As far as brain research techniques go, this one is one of the most painless, surpassed only by Near-Infrared (NIRS).
EEG measures the different frequencies of electrical activity moving along the surface of the brain, corresponding to the different emotional states and cognitive processes you might be experiencing at the time. The researcher will typically look at one or more of the five frequency bands one can experience (Delta, Theta, Alpha, Beta and Gamma), depending on the research question they are asking.
For example, a commonly used measure is Frontal Assymetry, where the alpha wave signal coming from the left frontal lobe is compared to that of the right frontal lobe. If the left’s signal is stronger, that’s an indication that the participant is especially interested in and motivated at a precise decision-making moment during the completion of the task in front of them. This could be navigating a website or finally selecting a product to purchase, for example. The information from use of EEG can help us tell whether you’re on the right track with your user interface design as it gives us an indication of purchase intent at that moment.
How does this work?
Simply put, your nervous system transmits nerve impulses between parts of the body, using electricity for communication. When you watch an action movie, the signal has to travel from the occipital lobe, where visual information signals from our eyes are processed, through a couple of other stops so that you can identify what you are seeing and understand it, then to the frontal lobe where you can then decide whether the movie is any good. All that information is relayed by electrical activity flowing between different areas of the brain. The role of EEG is to detect this flow of electricity, and the role of the neuromarketer is to understand what it all means.
Electrodes are placed at strategic positions on the participant’s head, with wires leading from them to the EEG machine. The machine detects the change in electric potential between the electrodes while the participant does something like complete a task, watch an advertisement or navigate a website landing page.
The resulting information looks quite intimidating, but can be cleaned up and interpreted to tell us all kinds of interesting information. Did you feel relaxed while listening to specific song? Were you genuinely excited by certain aspects of the TV commercial you just watched? Did you find a website or app particularly hard to navigate? You might not know, but we already do.
Pros and Cons
EEGs are a great tool because they are relatively non-invasive and easy to transport, making it easier to set up experiments. Most importantly, EEG can detect covert processing – processing that does not require a response – and gives insight into the implicit, subconscious responses of individuals during an experience.
Although EEGs can provide excellent, real-time insights into the emotional and attentional state of a consumer, they paint an incomplete picture. We need to know what it is they found interesting, or where they were bored. EEG is most effective when paired with technologies such as eye tracking and galvanic skin response – so all the insights gained are as useful as possible.
On the flip side, getting a clean enough EEG signal for reliable data takes a bit of practice, and a lot of working with the participants. Issues include “noise”, or signals from other electrical activity in the area. The signal-to-noise ratio for EEG is poor, so sophisticated data analysis and relatively large numbers of subjects are needed to extract useful information. The same sensitivity that allows EEGs to pick up the relatively tiny electrical activities of your brain makes it possible to detect interference from a nearby cell phone or the electrical signals from your blinking eyes. This makes EEG tricky to use in natural settings, or while the participant is moving naturally. However, EEG is still relatively tolerant of subject movement, unlike most other neuroimaging techniques. There even exist methods for minimizing or eliminating movement artefacts in EEG data.
EEG has very high temporal resolution (in terms of its ability to record a response in real time), on the order of milliseconds rather than seconds. However, it also has very poor spatial resolution, in that it cannot pinpoint activity happening within a specific area of the brain – it’s more of a global measure.
Similarly, interpreting the data requires some skill and the insights are most useful when combined with other technologies, such as the ones mentioned above. Don’t buy an EEG headset and expect sparkling results straight away.
How is this used by neuromarketers?
In addition to Neural Sense, Neurons Inc also has some excellent case studies where EEG is used in combination with eye tracking to assess the emotional and attentional experiences of customers while navigating a virtual store or seeing product packaging.
On the more creative side, Neural Sense used EEG in its Neurowine marketing project. A wine maker tried 21 different wine varietals with EEG apparatus on his head. The information from the EEG was used to determine which varietals he had enjoyed most, and those varietals were blended into a custom blend of “Neurowine”. The idea behind this was to cut away the preconceptions that could hold the wine maker back creatively, such as knowing the rules for which varietals blend best together, and focus on channeling more of his instincts around wine.