A flurry of new research is bringing the “Left Brain vs. Right Brain” debate back to life. The left cerebral hemisphere controls speech, academic, and analytical processes; the right cerebral hemisphere deals more with artistic and imaginative activities. But the hemispheres are always working together.
After becoming a staple of popular psychology and self-help books, the oversimplified split-brain model that put creativity only in the right brain and logic only in the left brain was challenged by many neuroscientists and fell out of favor with academia. This trend seems to be shifting again.
Improve memory by clenching your right hand.
A study released on April 24, 2013 by Ruth Propper and colleagues from Montclair State University found that hand clenching increases neuronal activity in the frontal lobe of the opposite hemisphere.
The right hemisphere controls (and receives sensory input from) the left side of the body and the left hemisphere controls (and receives sensory input from) the right side. The researchers stated that ‘such hand clenching is also associated with increased experiencing of a given hemisphere’s “mode of processing.” Together, these findings suggest that unilateral hand clenching can be used to test hypotheses concerning the specializations of the cerebral hemispheres during memory encoding and retrieval.”
The researchers found that clenching your right hand may help form a stronger memory of an event or action by activating the left hemisphere, and that clenching your left hand may help you recollect the memory later by activating your right hemisphere.
Creativity requires divergent thinking to connect seemingly unrelated memories and ideas in new and useful ways. It is fascinating to think that the simple act of squeezing a ball with your right hand while learning could improve crystallized intelligence in the left hemisphere; and later you could stimulate fluid intelligence by squeezing the ball with your left hand to engage the right hemisphere.
According to Ruth Propper, "The findings suggest that some simple body movements—by temporarily changing the way the brain functions—can improve memory. Future research will examine whether hand clenching can also improve other forms of cognition, for example verbal or spatial abilities." The authors clarify that further work is needed to test whether their results with word lists also extend to memories of visual stimuli like remembering a face, or spatial tasks, such as remembering where keys were placed.
Improve creativity by clenching your left hand.
In a similar study from 2010 titled “Unilateral Muscle Contractions Increase Creative Thinking” researchers from Israel used squeezing of the left hand to activate the right hemisphere. The researchers explain their rationale and findings: "Following the notion of relative importance of the right hemisphere in creative thinking, we explored the possibility of enhancing creative problem solving by artificially activating the right hemisphere using unilateral hand contractions. Participants attempted to complete the Remote Associates Test after squeezing a ball with either their left or right hand."
Abraham Goldstein who led the study concludes, "As predicted, participants who contracted their left hand (thus activating the right hemisphere) achieved higher scores than those who used their right hand and those who did not contract either hand. Our findings indicate that tilting the hemispheric balance toward the processing mode of one hemisphere by motor activation can greatly influence the outcome of thought processes.”
Squeeze a ball in your left hand to stop rumination.
In another study from 2012 published by the American Psychological Association, German researchers found that athletes can improve their performance under pressure simply by squeezing a ball or clenching their left hand before competition to activate the right side of the brain.
Right-handed athletes who squeezed a ball in their left hand before competing were less likely to choke under pressure than those players who squeezed a ball in their right hand which activated the left hemisphere.
“For skilled athletes, many movements, such as kicking a soccer ball or completing a judo kick, become automatic with little conscious thought. When athletes under pressure don't perform well, they may be focusing too much on their own movements rather than relying on their motor skills developed through years of practice,” said lead researcher Juergen Beckmann, PhD, chair of sport psychology at the Technical University of Munich in Germany.
"Rumination can interfere with concentration and performance of motor tasks. Athletes usually perform better when they trust their bodies rather than thinking too much about their own actions or what their coaches told them during practice," Beckmann added. "While it may seem counterintuitive, consciously trying to keep one's balance is likely to produce imbalance." This is directly linked to the function of the cerebellum and concepts of proprioception. I wrote a Psychology Today blog about the cerebellum and having grace under pressure recently titled “The Neuroscience of Calming a Baby.”
Beckmann notes that “Previous research has shown that rumination is associated with the brain's left hemisphere, while the right hemisphere is associated with superior performance in automated behaviors, such as those used by some athletes.” Because the right hemisphere controls movements of the left side of the body, and the left hemisphere controls the right side—the researchers theorize that squeezing a ball or clenching the left hand activates the right hemisphere of the brain and reduces the likelihood of rumination.
This study focused exclusively on right-handed athletes because the relationships between different parts of the brain are less well understood for people who are left-handed.
This research could have important implications outside athletics according to the authors. “Elderly people who are afraid of falling often focus too much on their movements, so right-handed elderly people may be able to improve their balance by clenching their left hand before walking or climbing stairs,” Beckmann said.
"Many movements of the body can be impaired by attempts at consciously controlling them," Beckmann concluded. "This technique can be helpful for many situations and tasks."