Читать книгу Social Psychology - Daniel W. Barrett - Страница 92

GSR, EEG, MEG, MRI, and fMRI have been among the most popular approaches to understanding the physiological bases of social behavior. However, researchers have also used positron emission tomography (PET), the physical induction of lesions directly on the brain, transcranial magnetic stimulation (TMS), and other methods (Beadle & Tranel, 2011; Decety & Cacioppo, 2011; Todorov, Fiske, & Prentice, 2011). PET provides an alternative way of imaging the brain that, like fMRI, examines blood flow. However, PET is a more invasive approach in that it utilizes injected radioactive or other substances and consequently makes it somewhat less appealing to social psychologists. Both lesion induction and TMS are disruptive techniques in that they impair normal functioning of the brain in order to see the effects of psychological processes. Lesioning involves causing irreversible damage to the brain, raising obvious ethical concerns. For this reason, lesion studies are usually conducted on animals or on humans who have already experienced brain trauma outside the laboratory (Beadle & Tranel, 2011). Had Gage’s severe brain injury occurred today, he would have been a prime candidate for one of these studies!

TMS uses a magnetic field to create an electric current that stimulates targeted areas of the brain and temporarily prevents normal functioning. For example, one study used TMS to briefly shut down the mirror neuron system in order to verify its role in imitating others (described earlier and again in Chapter 8). Researchers found that people’s ability to imitate others was significantly hampered, thus providing additional evidence of the function of mirror neurons (Heiser, Iacoboni, Maeda, Marcus, & Mazziotta, 2003).