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Lecture: FMRI: Functional Magnetic Resonance Imaging: Narrator: Listen to part of a lecture in a psychology class. Professor: The chapter on human personality in your book devotes some space to the fairly new field of personality neuroscience and functional magnetic resonance imaging, or F-M-R-I. So today, I want to talk about the use of FMRI for studying personality by using pictures of the brain, images that show the brain while it's processing information or stimuli. You're probably familiar with medical MRIs, which are used for diagnostic purposes. FMRIs are used mainly in research. Um.. the standard medical MRI only show the brain structures, but FMRIs show what is actually happening inside the brain; which parts are the most active at a given time ... in other words, how the brain is functioning. That makes them more useful than medical MRIs as a research tool. How do FMRIs work? Well, basically, they use magnetic fields to measure blood flow and oxygen levels in different parts of the brain, and this information can be used to determine which parts of the brain are activated when. So, in a sense, you're creating a map of the brain! Associating different parts of the brain with different actions, or emotions, or thoughts.. And now, FMRIs are being used to try to get answers to questions that psychologists have been asking for some time. Questions about personality, which has been defined as a set of psychological characteristics that remain stable over time. For example, are there different personality types? Is there even such a thing as a personality? Faith? Faith: Umm ... Wouldn't using FMRIs be a better way to answer those kinds of questions than traditional research methods? Like using questionnaires? I mean the book does say that questionnaires aren't very accurate. Professor: Well, that's true. Psychological questionnaires have their problems. After all, the information you get from questionnaires can be inaccurate, mainly because they rely on what people say about themselves ... and that can be influenced by a lot of extraneous factors, like memory, or a desire to present yourself in the best possible light etc. So, questionnaires can be somewhat unreliable, but still, questionnaires and other traditional methods shouldn't be discounted entirely. Paul? Paul: But why use questionnaires at all? I mean the book mentions an FMRI study that seems really good on the ... amygdala? Professor: Well, the amygdala studies. Yes, that is one FMRI study whose conclusions are well supported. The amygdala is a structure in the brain that processes fearful stimuli. In this study, you'll remember, subjects were shown photographs of angry and fearful faces and the researchers looked at how they responded, or should I say, how their Brains responded. Well, in some of the subjects, the amygdala was activated when the subjects viewed the pictures. We say it lit up ... We could see this change in the FMRIs. In other subjects, there was no change in the amygdala, and then, this is what's interesting, the same group of people were brought back a year later, and they were shown the same photographs and their reactions remained the same. For people whose amygdalas lit up the first time, it lit up again a year later. What this suggests, is that this aspect of personality, the response to fearful stimuli, is stable over time. So, it might be a personal counter argument to the claim you sometimes hear that personality, in fact, is not running stable over time. Paul: So there are problems then.. with other FMRI studies? Professor: I have to say that I think a lot of these questions around personality neuroscience is misplaced. The problem is over-interpretation. When researchers view FMRIs, they very often find significance where there really isn't any. The brain is incredibly complicated, and measuring the blood flow can't possibly tell you everything about the sophisticated processes going on at the neurobiological level. Paul: But what about those brain maps that they showed us in our book? Where part of the brain is associated with this or that thought. Professor: Here's how I see it. The maps of the brain that we get from FMRI studies are like geographical maps. They're useful, but, limited. They're not going to tell you much about the people of a country for instance. The same goes for brain maps. They tell you where there is heightened activity is in a region of the brain, but they don't tell you, for example, why people behave the way which they do. For that, we still need the support of traditional research methods. So, let's not throw those away just yet.