Student's brain flatlined during classes

From "A Wearable Sensor for Unobtrusive, Long-term Assessment of Electrodermal Activity" (by Poh, M.Z., Swenson, N.C., Picard, R.W. in IEEE Transactions on Biomedical Engineering, vol.57, no.5), a chart showing a single student's electrodermal activity over the course of a week. Note the neural flatlining during classtime. As Joi Ito notes, "Note that the activity is higher during sleep than during class." He also adds, "Obviously, this is just one student and doesn't necessarily generalize."

A week of a student's electrodermal activity (Thanks, Joi!)


  1. Note:  This is electro*dermal* activity, NOT brainwave activity.  Honestly, the interpretations of this study are kinda silly as people are presuming this is the level of cognitive activity and its nowhere near that level of data.

    1.  The brain does one thing and one thing ONLY, and that’s “be smart.”  Therefore, if the brain is ever not doing something, it is not being smart.  Ipso fatso.

    2. This is correct. An actual flatline in neuronal firing would indicate the person was dead. The brain is always active, even when a person is doing nothing at rest. This is a measure of changes in skin conductance: . This is *not* a measure of brain activity at all. With skin conductance measures, you should expect changes when the person is under stress, but also when they are just physically moving.

  2. Interesting that the graph lights up when the kid is doing homework or in lab, but the classtime is as flat at the TV time. I guess s/he is sitting at watching the teacher like a flatscreen.

  3. He is doing it all wrong.  I have never spent more than 30 min on homework in my life, but payed attention in classes.   Still had A-s most of the time and plenty of free time.

    Maybe he has terrible teachers.

    1. You took, for example, a calculus class and never spent more than a half an hour on homework?  You must be some kind of super genius.  A mere mortal like myself had to spend something like 40 hours a week to be at the top of my class in calculus.  I spent a few hours every night, and six or eight hours each day of the weekend.  Researching things I didn’t understand, doing it over and over until it was comfortable for me.  Third semester college Spanish was also very difficult and time consuming, when we got into the more difficult verb conjugations– there are something like 30 of them.  I always had to spend a lot of time to do well in school.  You must be quite gifted indeed!

      1. “You took, for example, a calculus class and never spent more than a half an hour on homework?  You must be some kind of super genius.”

        I think that’s the point of a post like that. 

    2. Not to bluntly rude, but what was your major?

      The resident business major in the suite in college probably spent 30 minutes or less per day on his work, and yet moaned about it.

      While the engineering majors spent 4+ hours per day on our work, not to mention once you started doing projects the countless hours spent in lab.

  4. The time scale is a little hinky too–from 19:00 to 00:00.  Not a huge deal, but the graphic displays this 3:00 time block as two segments, whereas the other 3:00 blocks are one segment.

    Also, I wonder what happened right before the 12:00 exam on day 6?

    1. No, stress. And probably a lot of movement. The measure is of skin conductance, which is sensitive to both of these facts. The measure doesn’t quantify brain activity as suggested in the original post.

  5. Bryan William Jones is right – this doesn’t directly indicate anything about the student’s mental activity.

    The EDA measures the activity of the sympathetic nervous system. The SNS is part of the autonomic nervous system – or that part of the nervous system that’s involved in reflex and non-conscious nervous actions. Specifically the SNS is related to the fight-or-flight response and some other housekeeping homeostasis actions.

    So, it’s no surprise that watching TV or sitting in class is less “stimulating” than everything else, including dreaming.

    Didn’t boingboing _just_ post something on how to report on science this morning?

    1. Everyone makes mistakes sometimes, and the way that skin conductance measures are talked about is often intentionally confusing, I think. It sounds more impressive to write about them as though they tell you something about cognitive activity rather than moisture in your skin. Cory is awesome and usually corrects these sorts of things when he makes an error so everyone gets the right info ultimately… you should just write him an email to let him know.

      I work in a brain science-related job and I see this sort of misunderstanding all the time. This one isn’t the worst one… I recently discovered that an impressively large number of people believe that the brain physically “lights up” in different places as they are activated… I blame Discovery channel animations and sloppy, unclear language in their narration scripts for this one.

  6. It’s easy enough to blame the teachers or the student’s lack of attention in class. However, some peoples’ brains just aren’t wired to efficiently process information presented auditoraly.

    For myself I attended every class in collage, and did my best to pay attention, but I still found that studying from my textbook was twice as efficient as learning in lecture.

    Lectures are gold for auditory learners, but mostly useless for visual learners like myself. 

    1. I study learning, and I am unaware of any such thing as a “visual learner” or an “auditory learner”, just for the record. I was also taught that this was a thing in grade school, and now that I’m a brain scientist, I can say with some confidence it’s really not. Everyone learns through many modalities. The more engaging the learning process, probably the quicker the learning, but the binary division of “visual” and “auditory” learners is BS.

      1. Some people are better at laying down long term memories through different sensory stimuli. My brother, for example, remembers almost every spoken word he hears whereas some people remember almost every image they pay attention to. Stating someone as an “auditory learner” wouldn’t mean that they only learn through hearing but that they can remember more details to build into a larger picture, which is needed to learn concepts and keep that information over a longer period of time (since that gives you more pieces of information to retrieve the information from, and as you extract certain details even more details attached to that larger concept would also be retrieved). Or at least that’s what I’ve rationalized from what I’ve studied of the brain. 

          1. That’s definitely true and we can’t get caught up in single senses when trying to learn, but in my mind we should maximize our learning by maximizing a sense (or two in combination). When we’re younger we (naturally) choose a hand dominance, and this allows for fine motor skills. In fact, if a child does not show a dominance by a certain age this is seen as a delay. Bilateral hand use is of course preferred, in the same way that the more senses we can use may be better (though be careful before calling a person with an amputation, or a person who is blind, disabled), but at the same time having a dominance is important for the details.

  7. This also doesn’t address the areas that are monitored by this sort of sensor.  I am assuming this is similar to EEG which cannot measure activity in deeper brain structures  Most likely areas like the hippocampus are active during these times as the student is absorbing and storing information rather than using more superior areas for critical thinking and cognition.

    Also what namnezia said.

    1. This is not similar to EEG, as it’s not measuring electrical activity but rather something more like moisture in the skin… unlike EEG, this is not a measure of brain activity at all.

  8. This looks like an actigraph report that measures physical movement and circadian rhythm, not brain activity. It’s usually worn like a watch and used to measure sleeping habits of people who say they have insomnia. Of course the student is inactive during TV watching and class.

  9. If we double his student loan interest rates, he’ll be sure to pay attention in class. 

  10. Interesting to note that the actual article that is linked is pretty clear to point out that: “Changes in skin conductance at the surface, referred to as electrodermal activity (EDA), reflect activity within the sympathetic axis of the Autonomic Nervous System (ANS) and provide a sensitive and convenient measure of assessing alterations in sympathetic arousal associated with emotion, cognition, and attention.”

    So, no claim to measure cognitive load, just “alterations” in cognition. As others point out, there is little alteration in attention or cognition when you are basically in a sedentary or meditative state. However, it seems to me that we should expect a lively, engaging learning experience to be more dynamic – to move us from receptive to constructive (or imaginative) states of cognition and back as the new material is presented and digested – and therefore we’d like to see more alterations in cognition and attention (and emotion for that matter, because we should feel something when we are learning, something like passion).

  11. It’s because electrodermal activity is affected by movement. You get activity when the person moves. That’s why there’s so little in class. You get some during tests because of stress.

Comments are closed.