Left brain, right brain

Three decades ago the Nobel Prize in Medicine was awarded in recognition of studies that are part of the reason people describe themselves as being “left-brained” or “right-brained.” Such terms can now serve as shorthand for, respectively, “more analytical,” or “more likely to find the fastest way out of the haunted house at the amusement park.”

Recent studies offer a reminder that despite the associations between a dominant half of the brain and a person’s abilities, both sides can and do work together to achieve results.

Source of creativity

Case in point: “We need both hemispheres for creative processing,” said University of Southern California researcher Lisa Aziz-Zadeh in a statement regarding the study published online March 9 to identify the source of creativity. Using brain scan analyses, she and her colleagues determined that while being visually creative (artistically arranging objects) activates the right side of the human brain, the left side of the brain is also engaged and, the researchers noted “supports creative processing.”

Another study published at the end of February came from German researchers at the Ruhr-University of Bochum and focused on how information flows between the two halves of the brain. Studies like these can help researchers studying conditions such as schizophrenia or dyslexia, which have been associated with brain development problems.

To learn more about what might prevent two halves of a brain to share information, the team worked with birds, which have distinct eye-information-to-side-of-brain relationships. They used pigeons, which apparently develop in the egg with one eye seeking the light on the other side of the eggshell and one eye hidden in darkness under a wing.

The presence or absence of light turns out to be crucial to brain development, so the researchers worked with birds that had been raised either with or without access to light. They said this is the first study to show how environmental factors such as the presence or absence of light to one section of the brain can influence the ability of both halves of the brain to exchange information.

In one set of tests, pigeons were trained to recognize several pairs of colored cups and correctly remember which colored cup in each pair contained the treat. For example, if the researchers offered a blue cup and a green cup, the treat was always in the green cup. If the researchers had yellow and purple cups, the treat was always in the yellow cup.

In training the birds to recognize the color pairings, however, the researchers put eye patches on so they only saw specific color pairs with one eye. So a bird with a patch on the right eye learned to recognize the blue and green cups and this information was stored in the left side of the brain. On the other hand, if its left eye was covered, the pigeon was provided with yellow and violet cups and the lesson was stored in the right side of its brain.

Colored pairs

After the training, the pigeons were allowed to use both eyes at the same time to find the treats out of the same pairs of color cups. The researchers reasoned that if the birds could find the treats in all of the cup pairs, then they had to be using both halves of their brains. They found that all of the pigeons were able to find the treat when presented with the same colored pairs of cups.

However, when the pigeons were presented with different pairs of colored cups, such as blue and yellow, those raised in light conditions did much better at finding the treats than the pigeons raised in the dark. In this case, the researchers noted, being raised in the dark had an effect on brain development, which in turn affected the birds’ ability to collate the information provided by both sides of their brains and figure out the hierarchy of the cup colors the way the other group of birds had done.

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