Research using new technologies has determined that a. brain activity does not vary depending on whether or not a stimulus is self-relevant. b. different areas of the brain are activated when american participants are shown photos of themselves as opposed to photos of others, but such differentiation does not occur among korean participants. c. different areas of the brain are activated when people are shown photos of themselves as opposed to photos of others. d. pet scans are not particularly informative for investigations of the self-concept, but fmri is.