Humans attempt to do many things at the same time, such as driving and chatting on the phone, or working and listening to music, and now research suggests why such multitasking may be possible: the brain appears to have its own control center.
Studies indicate that the physical "center" of the brain is located in the prefrontal cortex, on the left-hand front side, just above the temple. This is the first time that a "mastermind," which could control both visual and auditory activity, has been identified.
Before the new research, most scientists thought the brain processed sight and sound in different areas. Now it is believed that sight and sound influence each other.
"Many others have studied how matched audio-visual events, such as watching lips move and hearing speech sounds, are processed in the brain, but we wanted to draw attention to all of the audio-visual events humans are exposed to that are completely unrelated, like driving and talking on a cell phone or cleaning your apartment and listening to music," said Jennifer Johnson, lead author of the study and a researcher in the experimental psychology program at McGill University.
Johnson and colleague Robert Zatorre had test subjects listen to short, novel melodies and look at changing geometric shapes on a computer screen, both separately and at the same time. When multitasking, participants were asked to focus more on the music or the shapes at various periods.
Magnetic Resonance Imaging (MRI) recorded what happened in their brains.
The study's results were presented at the annual meeting of the Organization for Human Brain Mapping in Toronto.
When someone only listened to music, the auditory part of the brain, located just over the ears, activated. Visual stimulation by itself activated the visual area of the brain, toward the back of the head. Multitasking brought in the "mastermind" area that seemed to divide and control activity between the visual and auditory parts of the brain.
The researchers, however, said one activity usually takes precedence, which could explain why students who forever listen to loud music do not study as well as those who work in silence, and why drivers who chat on the phone often make errors in judgment.
"One of the events is distracting from the other," Johnson told Discovery News.
"We see in our study how focusing attention on one sense causes increased activity in that sensory area of the brain, but we also see how ignoring the other sense causes decreased activity in the other sensory area of the brain. This is likely why listening to raucous music or talking on the cell phone can lead to decrements in performance for the other tasks of studying and driving."
Another recent study on brain organization, authored by Michael Fox and colleagues at Washington University, supports the importance of the frontal cortex region in multitasking.
Fox and his team also noted that whenever an activity demands more attention, such as when a cell phone talking driver realizes he or she is about to run a red light, the driver's brain will then focus more on the driving than on the talking.
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