What are you studying?

When I tell people that I’m studying Cognitive Sciences, I usually receive blank stares. Then comes the natural follow-up question:

“What’s that?”

EEG, I tell them.

“Whoa, what is that?”

“It’s like…brain waves.”

People tend to stop at this point, and I’m pretty sure confusion plays a big role. Personally, I don’t like the term “brain waves,” but it seems to do the job. So I think I’ll write a little explanation. Here’s hoping it can help with the confusion.

Cognitive science is very interdisciplinary, and by that nature, rarther hard to define. Wikipedia defines it as “the scientific study either of mind or of intelligence.” There are many ways to do that, and my field of study would mostly likely fall into the category of cognitive neuroscience, where one tries to define neural correlates and mechanisms for various cognitive functions — the holy grail being our consciousness.

EEG, or electroencephalography , is one tool scientists can use to study these neural mechanisms. The neurons in our brain generate tiny electrical currents that can be recorded on the scalp using electrodes. We have subjects perform certain visual tasks, and we record and study changes in the electrical activity related to these visual tasks. We usually look for changes in the frequency and amplitude of these currents.

So, for example, a very basic demonstration of this would be to record a subject viewing a black and white grating pattern flickering at, say, 12 Hz — that is, 12 times per second. In our recording, we will also see a 12 Hz signal. This means that somewhere in the brain, mostly likely in the visual cortex, there are neurons that are responding to the flicker at the same rate.

Our studies make full use of this effect: we can present one stimulus at one frequency, and another at a different frequency. We can then separate and track the brain’s response to both stimuli by locking on to the appropriate frequency. Such a technique is called “frequency tagging.”

Edit: This was intended to be a two-part post. I’ve decided to cancel the second part…