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I'm aware that all tasks that a person undertakes involve both halves of the brain. At the same time, there are studies of people who have communication between brain halves severed or suppressed and they produce dramatically different drawings of the same object with different hands.

This makes me ask - is there some sort of a (non-FMRI) test that involves drawing or other activity and can:

  • Determine if one half of the brain is dominant at the given moment
  • Determine if communication between brain halves is fluctuating over multiple days
  • Determine if one half of the brain does not consistently function at the same level of activity?

I'm aware of this Ted talk: My stroke of insight, in which a neuroscientist describes the experience of having a stroke affect one half of her brain, dramatically altering her perception and ability to process real world information. For example she describes being unable to recognize digits in a phone number and "hunting" for the right digit by tracing its shape on the phone.

The images below were made using 100% input from one brain half and 0% from the other. I'm interested if different levels of activity in brain halves, like 100%/50% or 100%/80% or 60%/70% would also create noticeable differences in style.

enter image description here

enter image description here

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  • $\begingroup$ The first image (with house) is really interesting. One figure drawing teacher asked me to do some figure drawings (after a live model) with my non-dominant hand. I noticed: in drawings with the non-dominant hand the proportions are intuitively accurate, while the lines are shaky and small details are therefore often misplaced; drawings with the dominant hand have straighter lines and better detail, but the proportions are usually false, often in a subtle way and hard to pin down. Don't know if that will give you any useful ideas, but those houses perfectly illustrate my experience. $\endgroup$
    – user3116
    Apr 11, 2014 at 13:59
  • $\begingroup$ Btw, @AlexStone, where are those drawings from? $\endgroup$
    – user3116
    Apr 11, 2014 at 19:42

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You say you are "aware that all tasks that a person undertakes involve both halves of the brain". Then, On what kind of patients would this hypothetical test be suitable as healthy people use both hemisphere and split brain use just one hemisphere depending on the drawing hand ?

If you refer to healthy patients I don't think such a test is possible. For the moment left-brain/right-brain dominance is usually considered as a neuromyth.For example:
- this blog article http://www.psychologytoday.com/blog/brain-myths/201206/why-the-left-brain-right-brain-myth-will-probably-never-die
- or this paper http://www.nature.com/nrn/journal/v7/n5/full/nrn1907.html .

Maybe some tests (drawing or whatever) would correlate a bit with partial and short term hemispheric activation with desirable inter-individual differences. But aiming for a test bringing more than that is in my humble opinion vain hopes, as hemispheric dominance on healthy subjects has weak (or no) scientific ground.

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    $\begingroup$ Hemispheric dominance is often overstated, but hardly mythical. Do you consider split-brain patients unhealthy? They use both hemispheres when each has independent access to information, as when an object appears in the center of both eyes' visual field. $\endgroup$
    – Nick Stauner
    Apr 12, 2014 at 1:31
  • $\begingroup$ Maybe unhealthy was not the good term, I apologize for that. I am not a native english speaker. As I don't know if some kind of brain dominance can be seen on split brain patients, I excluded them from my considerations. I know that brain dominance may concern some faculties (like language) with inter-individual differences (e.g. men Vs women). But my readings made me skeptic on the subject of a global hemispheric dominance. I would be happy to update my position if you can grab the sources that make you think the opposite. Best regards. $\endgroup$
    – brumar
    Apr 12, 2014 at 13:54
  • $\begingroup$ No need to apologize; just wanted clarification. You're wise to be skeptical about a lot of claims out there, but even "weak scientific ground" is a not-so-skeptical claim without thorough knowledge of the research. My graduate advisor taught me to avoid making negative claims like that about existing research, though it would certainly help justify my own research when I'm claiming to fill one of those gaps with it...That's one of the many prices of practicing strict skepticism! Anyway, here's an answer in which I mentioned a relevant video: cogsci.stackexchange.com/a/5459/4086. $\endgroup$
    – Nick Stauner
    Apr 12, 2014 at 17:56

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