Are You Left-Brained or Right-Brained, or Maybe Not?

In an elementary school class, my teacher decided we would find out which of us is “left brained” and “right brained,” so we sat completing a checklist. “I like art.” I do, so a check for right brain! “I like math.” I do, so check for left brain! I had the same sum for both, and I guess the only child in class unsure what group I belong in. So I asked my teacher about my brain. “Stop disrupting the educational process,” she said with a lamenting sigh. I don’t remember exactly if those were her words. Maybe not, since I heard that expression a lot as I got older. Memory is funny like that. But I do remember the feeling, like I’d asked something wrong just for being curious.

Your certificate gives you three scores

1. Your brain hemisphere dominance, based on how you use your hands, legs, and eyes
2. Your "left brain" or "right brain" personality, based on questions about your personality
3. How well you spotted common myths about the brain

Let's explore each with a little more depth.

Your first score Brain Hemisphere Lateralization to Right-Side & Left-Brain shows how much your brain is lateralized so one side is dominant or the other. Your score is based on your physical habits, like which hand you write with or which eye you use to focus on an object. These patterns give us clues about which side of your brain (your hemisphere) might be more active for body control. Table 1 shows how to interpret your scores.

We can roughly divide scores of 0 to 100 into thirds. About 85% to 90% of people are right handed and most people score 67 to 100 (figure 1). Their left brain hemisphere is dominant and they're typically right-handed. About 10% to 12% of people are left-handed. Similarly, we can describe people scoring about 0 to 33 as having a right brain dominance. People with scores of about 33 to 67 are ambidextrous. My score is 40. Some people with ambidexterity are equally capable with their left and right body sides. That's not me. I somehow ended up with dominance for different things on different sides. I write, strike a match, and unlock doors with my left hand. But I kick a ball with my right leg, cut using scissors, and even when I sign with a trackpad or mouse I use my right hand.

Our brains are divided symmetrically into left and right hemispheres each connecting with afferent and efferent neurons to receive sensory information and control actions from the opposite half of the body. For example, persons writing with their right hand are doing so with feedback to and instruction from their left brain hemisphere. Aspects of different cognitive functions such as language, reasoning, spatial processing, facial processing, and music are lateralized more to one hemisphere or the other (e.g., Springer & Deutsch, 1998). The most startling results illustrating this lateralization began with Sperry’s studies of split-brain patients whose corpus callosum, bridging the hemispheres, was severed surgically as a last-ditch effort to help people suffering from severe epilepsy (e.g., Gazzaniga et al., 2009).

Your first score Brain Hemisphere Lateralization to Right-Side & Left-Brain shows how much your brain is lateralized so one side is dominant or the other. Your score is based on your physical habits, like which hand you write with or which eye you use to focus on an object. These patterns give us clues about which side of your brain (your hemisphere) might be more active for body control. Table 1 shows how to interpret your scores.

The Brain Lateralization Hemispheric Dominance Scale has very high inter-item reliability with a Chronback's alpha α of .908.
It’s a way of saying the questions all seem to measure the same thing. Even though they look really different our answers are consistent. Writing, kicking, brushing teeth - these behaviors seem unrelated, but your answers tend to line up. When a scale has high alpha (above .7), scientists take it as a sign we're tapping into a meaningful underlying construct.

Even though I was a science major, when I was an undergraduate student I loved taking studio art and graphic design classes. It was the early days of graphic designers using computers. One of my professor was fascinated by me. I write and paint with my left hand, and he described my aesthetic as "organic," which means very fluid, like nature, and having feminine energy.

Later in the semester, we had a computer assignment. I use my right hand with a mouse even when I'm drawing. To him, my aesthetic became less organic. Maybe as somebody who is ambidextrous, I have two personalities in my brain? What about you?

Your personality score came ranges from 0 for an extremely right brain (left-handed) personality to 100 for an extremely left brain personality. It's from how you rated yourself on traits like creativity, organization, and logic. The idea here all of the internet and pop culture is people are either logical, systematic, and detail-oriented (left-brain types) or creative, emotional, and big picture people.

It’s a fun idea.

It goes along with how our brains really are lateralized with hemisphere dominance.

But it’s also a myth.

Data from people like you on the personality scale has a Chronbach’s alpha of only .554, which is low (figure 2). The items don’t really hang together. Even if items sound similar (e.g., creativity and intuition), they don’t consistently point to a real, underlying “brain personality.”

Taking it further as our scatterplot shows, when we compare personality scores to brain dominance scores, we find almost no connection at all. Most students have a right-side physical bias (left hemisphere dominant), but their personality scores are all over the map (figure 3).

When I reflect on my graphic design class, I feel it's not real my brain hemisphere creating differently, but the medium. I intuitively know how to express myself with pencil, charcoal, and paint. But using a computer feels rigid to me and I'm just not as skilled expressing my creativity.

Your Brain Myths endorsed ranges from 0 to 5. Please know it's totally okay if you fell for many myths. They're really common beliefs, but let's clarify what neuropsychology shows us about the brain:

1. We use 100% of our brains (not 10%)
2. There is neurological component to depression but medicine is not more helpful than therapy. Both help depending on you.
3. Nobody is good at multitasking. In actuality our brains are quickly shifting back and forth across tasks and there's always a cost to switching. Young adults only think they're better at multi-tasking. In actuality, everybody sucks!
4. Human memory is not perfect; it's not at all like a recording. For example, I began with a personal story where it's possible my teacher didn't say I was disrupting the education process and I am experiencing interference because I heard that phrase so much as a kid.
5. Finally, as we see with this activity, there's no such thing as a left or right brain personality.

You’re learning science isn’t just about finding answers. It’s about asking better questions. The myth of left-brain vs. right-brain personality is built on grains of truth (like hemisphere specialization), but takes leaps that don’t hold up to evidence.

Critical thinking means not just accepting ideas that seem right. We don't just think. We find out.

You don’t have to choose between being logical or creative. You can be both. You are both. You’re not “left-brained” or “right-brained.” You’re whole-brained. Human. Wonderfully complex.

Back in my elementary school classroom, I thought my love for both art and math meant something was wrong with me. So for a while, I gave up on art. I stopped lessons know I wasn't as good as other kids. I decided to become a serious, grown-up scientist instead. But I found my way back to art. And I see how science and creativity live side by side.

So if there’s something you love that doesn’t “fit the box,” keep it. Please don’t pick sides. Just stay curious and grow.

Uneasy Feelings about Your Results?
Please remember your results with any activity are not who you are. Your results are a 'snapshot' of a moment when you did an activity. It's just one measure, a single thread, of the many strands of who you are. Any result is a guess with statistical error. And it's possible the measure is flawed in a way so it doesn't work for you. Please do not think of your results as definitive dogma. Instead they're a starting point for our self reflection. Please keep in mind too, self-reflection can feel uncomfortable. "Bad" feelings are not actually bad. They're information. So, even if your activity result is inaccurate and flawed, you might ask yourself what your feeling is trying to tell you? Trusted teachers, friends, and therapists can be helpful. I wrote an essay elaborating with concrete examples how we can appreciate uneasy feelings about our activity results.

Scholarly Information?
You're welcome to use Copernican Revolution activities and essays for your thesis and studies. Having information about scholarly aspects like psychometric data, activity design details, and norm calculations may help. The primary focus of my essays is connecting educated laypersons with psychology. To help people like you, with advanced academic interests, I add an appendix with each activity.

Gazzaniga, M. S., Ivry, R. B., & Mangun, G. R. (2009). Cognitive neuroscience: The biology of the mind (3rd ed.). New York: Norton.

Hines, T. (1987). Left brain / right brain mythology and implications for management and training. Academy of Management Review, 12(4), 600–606.

Lilienfeld, S. O., Lynn, S. J., & Beyerstein, B. L. (2010). 50 great myths of popular psychology. West Sussex: Blackwell.

Springer, S. P., & Deutsch, G. (1998). Left brain, right brain: Perspectives from cognitive neuroscience (5th ed.). New York: Freeman.