News Editor: Renato M.E. Sabbatini, PhD
Where the Brain Makes Decisions
Using a revolutionary method of imaging the brain, researchers from the Open University (OU) and the London
Business School say they have identified the brain region that becomes active as the shopper reaches to the supermarket
shelf to make their final choice.
If that sounds a frivolous finding, the scientists involved insist their work has serious applications.
"How people use their brains to learn, record and store memory is a fundamental question in contemporary neuroscience," said Steven Rose, director of the brain and behavior research group and professor of biology at the Open University.
Beyond the local supermarket, Rose and his team believe the findings could go on to show the brain processes behind the conscious decisions people make when it comes to important life choices, such as selecting a partner or career. The research may also one day help manufacturers and marketers shape advertising and branding strategies for their products.
The scientists used a technique known as magnetic encephalography (MEG) -- the fastest of all scanner methods -- to measure the minute magnetic fields around the brain and identify regions that are active during the second or so it takes for a person to make their shopping choice.
Subjects were taken on an 18-minute virtual tour of a supermarket. During regular pauses in the tour, they were asked to make a choice between different brands and products on the shelves by pressing a button. Researchers found that the brain was hugely active during the 2.5
seconds it took for the button press to be made.
"Within 80 milliseconds their visual cortex responds as they perceive the choice items," Rose said. "A little later, regions of the brain associated with memory and speech become active."
More interesting for the researchers, however, was what happened as consumers made their final choice.
"After about 800 milliseconds -- and this was the surprising thing -- if and only if they really prefer one of the choice items, a region called the right parietal cortex becomes active. This then is the region of the brain involved in making conscious decisions -- in this experiment about shopping choices, but maybe for more important life choices too," Rose said.
Other scientists gave a guarded welcome to the findings of the OU researchers -- Rose, Professor Stephen Swithenby, Dr. Sven Braeutigam and Dr. John Stins -- who will publish their findings in the next issue of the journal Neural Plasticity.
Michael Miller, professor and chair in the department of neuroscience and physiology at SUNY Upstate Medical University, said that MEG scans provided a unique insight into the real-time activity of brain regions in humans and animals. "They are very insightful. There is a growing literature about the role of the prefrontal cortex and other areas that are involved in volitional activities," he said.
Dr. Wise Young, director of the W.M. Keck Center for Collaborative Neuroscience and a professor at Rutgers University, said that the finding was "interesting" although not particularly surprising or groundbreaking.
"The parietal cortex has been conjectured as one of the sites of decision-making in the brain. Because that part of the brain is showing activity during decision-making does not necessarily mean that the decision is actually made in that part of the brain. Also, the authors examined only several sites on the brain and there may be parts of the brain that were activated but they did not record," he said.
Young said that for centuries scientists have struggled with the question of whether function is localized or distributed in the brain.
"Much data suggests that many functions are quite broadly distributed, the brain is quite plastic and quite remarkable recovery can occur after injury to large parts of the brain. On the other hand, it is also clear that some areas are more important for some functions than others," Young said.
Dr. Susan Bookheimer, director of brain mapping center behavioral testing and training laboratory at UCLA, was more skeptical. "When I first read this, I thought it was a joke. It is not an interesting finding," she said. "The investigators have added all this supermarket stuff to make it more appealing to a general audience, but you'd find the same thing if you just used pictures of dots, for example."
While Bookheimer agrees there are areas of the brain responsible for
making choices, she believes the real story is much more complex than that presented by the OU study.
"We must integrate knowledge before we make a choice," she said. "Many, not all choices, involve an emotional component controlled by a different area of the brain. Others require integrating information from multiple choices. We have to generate a response, search available responses and then initiate a plan to demonstrate the choice. It is likely that only this last process was involved in the study here -– the process of directing one's reach toward the goal."
By Dermot McGrath
Wired News, April 22, 2002