Hockenbury Discovering Psychology 5th txtbk

Ethics in Psychological Research351. Brain-imaging studies usually involve a small numberof subjects. Because of the limited availability and the highcost of the technology, many brain-imaging studies havefewer than a dozen participants. With any researchinvolving a small number of participants, caution must beexercised in generalizing results to a wider population.2. Brain-imaging studies tend to focus on simple aspectsof behavior. Even seemingly simple tasks involve thesmooth coordination of multiple brain regions. As JeromeKagan (2008) observes, “An event as simple as theunexpected sound of a whistle activates 24 different brainareas.” Thus, it’s naïve to think that complex psychological orbehavioral functions can be mapped to a single brain center.Sleep Rested3. Brain imaging may add little to explanations of apsychological process. For example, although brainimaging might point to a particular brain structure as beinginvolved in, say, fear or romantic love, knowing this may notadvance our understanding of the psychological experienceof fear or romantic love.4. Brain imaging is not necessarily a more “scientific”explanation. As psychologist Paul Bloom (2006) points out,“Functional MRI seems more like ‘real’ science than many ofthe other things that psychologists are up to. It has all thetrappings of work with great laboratory credibility: big,expensive, and potentially dangerous machines, hospitalsand medical centers, and a lot of people in white coats.” Tobe truly useful, brain activity snapshots of a particularbehavior must be accurately interpreted within the contextSleep DeprivedFunctional Magnetic Resonance Imaging (fMRI) fMRI combineshighly detailed images of brain structures with moment-bymomenttracking of brain activity. In this experiment, fMRI wasused to compare emotional responses to disturbing visual imagesin two groups of participants: participants who had had a normalnight’s sleep and sleep-deprived participants who had beenawake for 35 hours (Yoo & others, 2007). The circled brain region,called the amygdala, is known to be involved in emotion.The scans revealed that the amygdala was much moreactive in sleep-deprived subjects (circled in red) than in participantswho were not sleep-deprived (circled in green).of existing psychological knowledge about the behavior(Cacioppo & Decety, 2009; Henson, 2005).Magnetic Resonance Imaging (MRI) MRI scans can produce ahighly detailed image of the brain, showing “slices” of the brainfrom different angles. The yellow dots highlight the brain regionthat was significantly larger in experienced London taxi drivers,known for their encyclopedic memory of London streets, as comparedto control subjects (Maguire & others, 2000, 2006). Thisregion, called the hippocampus, is known to be involved in formingnew memories. This landmark study provided solid evidencefor the once revolutionary idea that structures in the adult brainchange in response to experience and learning.Looking at Brain-Scan ImagesWhat should you notice when you look at the brain-scan imagesin this text? First, read the text description so you understandthe task or condition being measured. Second, read thebrain scan caption for specific details or areas to notice. Third,carefully compare the treatment scan with the control scan ifboth are shown. Fourth, keep the limitations of brain-scan technologyin mind. And remember, human experience is much toocomplex to be captured by a single snapshot of brain activity(Racine & others, 2005).functional magnetic resonanceimaging (fMRI)A noninvasive imaging technique that usesmagnetic fields to map brain activity bymeasuring changes in the brain’s blood flowand oxygen levels.