Public Release: 

Personal decisions exercise the emotional part of the brain

University of Washington

CHICAGO (Nov. 26) -- People use the emotional parts of their brain to make so-called rational personal decisions, according to a University of Washington researcher.

"Neuropsychologists have begun to believe that emotional and rational parts of the brain may be more closely intertwined than previously thought. Our imaging research supports the idea that every time you have to make choices in your personal life, you need to "feel" the projected emotional outcome of each choice -- subconsciously, or intuitively. That feeling guides you and gives you a motivation to make the best choice, often in a split second," says Dr. Dean Shibata, assistant professor of radiology at the University of Washington.

Shibata presented his findings at the 87th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA here the week of Nov. 26. Shibata did the research while on the faculty at the University of Rochester School of Medicine.

During the brain scans, Shibata showed 11 people a series of personal questions, such as asking them to choose a preference for "warm bath or dinner?" The subjects were then supposed to roll the question over in their mind for a few seconds while their brain activity was measured. Shibata also asked the subjects more impersonal, cost-related questions, such as, "What would cost you more - a burglary or theft of your car?"

The goal was to measure what happens to the brain while making personal decisions, as opposed to what seemed like impersonal decisions. "The point was to test the hypothesis that when people make decisions that affect their own lives, they will utilize emotional parts of the brain, even though the task itself may not seem emotional," Shibata says.

Shibata is not alone in this view, and says he was inspired by the work of neurologist Antonio Damasio, who has worked with patients who've suffered brain damage. Evidence suggests that when someone suffers an injury to the part of the brain that governs emotion, the person may have normal memory and be able to solve abstract problems. But the person will often have trouble making routine, rational decisions for themselves, such as when to make a doctor's appointment. They seem to get caught in 'infinite loops' where they are unable to prune through the various options and make a decision.

"You'd think that when to make a doctor's appointment would be a logical decision. Logically - what's the consequence of missing the appointment? What are the best times of the day for me? It seems like something a computer could do. But our data suggests that those decisions are based on emotional outcomes - how we feel about what kind of outcomes we would like. In the case of a doctor's appointment, we may choose a time because we remember our emotional reaction sometime when we failed to make an appointment for something."

One example Shibata uses is when someone has to choose whether or not to put on a seat belt: "That 's not a rational decision, even though you think it might be. 'It will help prevent me from being in an auto accident' - That seems like a very rational king of thing. But it's also very emotional - you can envision that you are going to die, that you could hit your head on the windshield - if you don't put your seat belt on."

Shibata hopes his findings assist people who treat disease of the brain, including mental illness: "Hopefully by understanding how our rational and emotional sides come together, we can understand more about psychiatric diseases such as schizophrenia, and ultimately how to treat them."

Shibata scanned the brains of volunteers using a relatively new technique called functional magnetic resonance imaging (fMRI). This technique is still largely a research tool, but shows promise in helping to localize vital areas of the brain before surgery and is sometimes performed on patients at UW Medical Center. Although MRI scanners are usually used to look at anatomic structures such as tumors, fMRI measures brain activity, and "lights up" areas of the brain being used at a given time.

People making personal decisions showed more activity in the ventromedial frontal lobe; they didn't use that part of the brain when they were thinking impersonally about comparing the financial cost of two events. The ventromedial frontal lobe is known to be involved in emotions and patients with injuries in this area often have alterations in their personality. It is also one of the areas in which abnormalities have been found in depression and schizophrenia.


The RSNA, based in Oak Brook, Ill., is an association of more than 30,000 radiologists and physicists in medicine dedicated to education and research in the science of radiology.

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