There's been a meeting of the minds at Duke in the study of consciousness. A philosopher and a cognitive psychologist are working with neuroscientists to find links between the biological function of the brain and consciousness.
"The mind-body problem has been around for centuries and I find it immensely exciting to try to evaluate age-old problems and claims about the mind in light of a huge amount of information we have been uncovering about the brain," said Gƒ‚‚ ‚ºre, assistant professor of philosophy. Gºre, who also holds adjunct appointments in the department of psychology-experimental, the Center for Cognitive Neuroscience and the Brain Imaging and Analysis Center, is the lead researcher in a study at Duke on "change blindness."
Change blindness refers to the phenomenon when someone is temporarily unable to identify the difference between two separate but very similar images. In experiments, the original image flashes briefly on a screen, then after a split-second break of gray-screen, another nearly identical image follows. The period of time it takes the viewer to recognize the element that has changed from the first to the second image varies, but once identified, the change seems starkly obvious.
In the past, change blindness studies involved self-reporting by the viewers. Sometimes they reported a sense of knowing something was different before being able to actually identify the change. The observations were interesting and provided some fodder for theories, but analysis was limited.
With the advent of sophisticated brain imaging used in neuroscience research, the study of change blindness takes on a new dimension. Using functional MRI (magnetic resonance imaging), researchers are able to "take pictures" of the brain while it processes the puzzle of the different images. Now they can map the areas of the brain that become active while searching for the change and correlate that information with the viewer's report of recognizing the change. The result may be better understanding the mechanisms of visual perception, and the role of consciousness.
"Change blindness has been studied very carefully, in terms of how long it takes for you to notice a change and what kind of changes are more readily detectible and what kinds of change take longer to see," Gºre said. "But nobody really knows what happens in the brain just when you notice this change, as opposed to when you are doing the search with the difference right in front of your eyes but not quite noticing it."
Gºre and Scott Huettel, a cognitive psychologist and postgraduate fellow in the Brain Imaging and Analysis Center, began their research after the philosopher received a fellowship from the John McDonnell Foundation, which has played an important role in advancing cognitive neuroscience issues the past decade. Gºe is one of 15 philosophers -all working on questions involving neuroscience - sharing a $1 million grant over five years.
Gºre is investigating the scope of unconscious processing in the visual system. In the portion of his research dealing with change blindness, he is also studying the role of conscious awareness in visual perception, and the funding helps pay for his research time with MRI, among other things.
"These days biology and neuroscience are really the rising stars in science and, in parallel, I think philosophy of neuroscience will become the emerging field within the philosophy of science," Gºre said.
The fields complement each other, he added.
"Neuroscientists, as well as philosophers and psychologists, are interested in the role that consciousness plays. How is it that we get a unified representation of the world, for example, when we open our eyes and see things? What is it that happens in our brain such that in our minds we get a coherent full representation of the world? These are questions that philosophers have been asking themselves forever."
Analytic philosophers, he said, specialize in formulating questions in a clear and crisp way "so that we can weed out bad questions. If you start with a bad question, you may never get to the answer." Contemporary philosophers also focus on setting the conceptual framework for problem solution, something valuable to scientific study.
"I think scientists need philosophers as much as philosophers need scientists," he said.The interdisciplinary approach at Duke has already yielded some valuable information. Gºre and Huettel reported initial findings at a national conference in late spring and, with Gregory McCarthy, director of the Brain Imaging and Analysis Center, expect to soon publish results of the first phase of their studies.
"For the first time, we demonstrated (in the first phase of the study) what goes on in the brain and how there are different areas of the brain that become active when you are doing the different phases of this process," Gºre said. "When you're just looking at a scene, some part of your brain is active. When you start searching for a change, other parts become active. Once you notice a change, then another part becomes active. I can actually correlate what goes on in your brain with your subjective reports of what you are doing.
"In the old times, if I were just a behavioral psychologist and you were sitting in front of the screen trying to do a search, I would have no clue until you uttered something. But now we have better tools. We can literally see what elapses in brain activity until conscious perception occurs. We can predict, 'Now she's going to see it.'"
In the next stage of their change blindness study, Gºre and Huettel are going after more advanced processes. They've turned their search to the phenomenon of "mindsight," that sense which some viewers report that something has changed though they can't put a finger on the change. The philosopher thinks there's something in the mind that prepares the viewer to notice change, a stage of preparation between unconscious perception and conscious recognition that functional MRI may help explain.
Written by Karen Hines.