Raise Your Left Hand for Greater Creativity!

For decades, psychologists have tried to find creativity in the brain. Because of a 19th century belief that creativity was related to mental illness, and a corresponding belief that left handed people were more likely to be mentally ill (or "degenerate" as some writers put it!), some 19th century scholars thought that creativity would be located in the right hemisphere--because the right hemisphere controls the left side of the body.

In the 1960s, Dr. Roger Sperry began to study a special group of people: patients with such severe epileptic seizures, that the only known cure was to surgically cut apart the two halfs of the brain. This cured the epilepsy, but it had serious side effects: after all, if the two sides of the brain can't talk to each other, then whatever your right eye sees, only the left side of the brain is aware of it.

Sperry's study, and others like it in the 1970s and 1980s, concluded that creativity is a complex, whole brain activity--involving both the left side and the right side. In 1988, one top research team concluded that “a greater than usual hemispheric interaction” happens during the most creative moments.* (You can read more about this in my 2012 book Explaining Creativity.)

So I was surprised to read a new study just published in 2010, titled "Unilateral muscle contractions enhance creative thinking," that seems to show that creativity is associated with the right hemisphere.** The research team worked with 40 people, and gave them all a measure of creativity known as the Remote Associates Test (or RAT) that was developed back in the 1960s. Each of the 25 RAT items contains three words, and the task is to identify a fourth "target word" that's related to all three words (example: pie, crab, pine-->apple). The three-word items are designed so that you have to activate multiple conceptual clusters in your mind before you can identify the target word--hence, "remote associates". This is based in research showing that more original ideas tend to combine more distant concepts; combinations of similar or closely related ideas tend not to be as creative and original.

Before they took the test, they were subjected to one of three conditions. Fifteen people were told to squeeze a rubber ball really hard for a total of four minutes, with their left hand (with a few rest breaks). Fifteen other people were told to squeeze the ball with their right hand. The ten remaining people were the control group; they didn't squeeze the ball at all.

And guess what? RAT scores were highest for the left hand squeeze (which activates the right hemisphere), lower for the control group, and lowest for the right hand squeeze. The left-hand squeezers solved an average of 12 of the 25 triplets; the control group solved 10; and the right-hand squeezers solved 8. So two different things are going on: First, activating the right hemisphere with bodily activity enhances the ability to make remote associations; and second, activating the left hemisphere actually inhibits association ability.

Scientists always love it when the existing scholarly consensus is challenged by a contrary finding, and this finding is really surprising. Their research is sound--good methodology, good statistics, et cetera, and I believe the effect is real. So now we need to do some more research to figure out what's really going on, and how we can reconcile this new finding with the large number of prior studies showing no hemispheric assymmetry in creativity. I think we should start by trying to replicate this study with a different population; they did the study in Israel, so maybe one of my U.S. colleagues can attempt to replicate it in the U.S.

The practical implications aren't really very clear. After all, most people are engaging both sides of their bodies at about the same level almost all the time. And it's interesting that the researchers didn't evaluate a fourth possible condition: have some of the people squeeze two balls, one in each hand. I wonder what would happen then? Let's replicate this study, and add in this fourth condition.

*Bogen & Bogen, 1988, p. 295.

**Goldstein et al., 2010, Psychonomic Bulletin and Review, 17(6), 895-899