There have been prior clues that creativity benefits from ample cross-talk between the brain hemispheres. For example, patients who've had a commissurotomy - the severing of the thick bundle of nerve fibres that joins the two hemispheres - show deficits on creative tasks. Now Elizabeth Shobe and colleagues have provided the first evidence that creativity is boosted by an intervention designed to increase hemispheric cross-talk.
Shobe's team tested 62 participants on a version of the "Alternative Uses Test", a divergent thinking challenge that involves dreaming up unconventional uses for everyday objects such as bricks and newspapers.
An important factor that the researchers took note of was the participants' handedness. Prior research has suggested that people who have one hand that is particularly dominant, so-called "strong-handers", have less cross-talk between their brain hemispheres compared with people who are more ambidextrous or "mixed handed".
After an initial attempt at the creativity task, half the participants spent thirty seconds shifting their eyes horizontally back and forth. This exercise is thought to help increase inter-hemispheric communication. The remaining participants acted as controls and just stared straight ahead for 30 seconds.
The key finding is that on their second creativity attempt, strong-handers who'd performed the horizontal eye movements subsequently showed a significant improvement in their creativity, in terms of being more original (i.e. suggesting ideas not proposed by others) and coming up with more categories of use. Staring straight ahead, by contrast, had no effect on creativity.
Another finding was that, overall, the mixed-handed participants performed better on the creativity task than the strong-handers, thus providing further evidence for a link between inter-hemispheric interaction, which mixed-handers have more of, and creativity. But it also turned out that mixed-handers didn't benefit from the horizontal eye movement task. It's as if they already have an optimum amount of hemispheric cross-talk so that the eye movements make no difference. This meant that after the strong-handers had performed the horizontal eye movements, their performance matched that of the mixed-handed participants.
The researchers also showed that, for strong-handers, the beneficial effects of the eye movement exercise lasted nine minutes for originality, but just three to six minutes in terms of coming up with more categories of use.
"Our findings may not apply to more unique populations who are characterised as 'highly creative'," the researchers said, "nor can we conclude ... that the thirty seconds bilateral eye movement task will turn an average individual into an artist, poet, scientist, philosopher, actor or sculptor. However, we certainly do propose that the ... eye movement task will result in a temporary increase in strong-hander's ability to think of creative uses for various house-hold objects."
These new findings complement research published in 2008 showing that horizontal eye movements aid memory performance for strongly-right handed people, but impair the performance of left-handers and mixed-handers.
Shobe ER, Ross NM, & Fleck JI (2009). Influence of handedness and bilateral eye movements on creativity. Brain and cognition, 71 (3), 204-14 PMID: 19800726