An Fmri Study of Moral Judgment

Abstract:
Recent reports on patients with lesions of the prefrontal cortex indicate that this region is crucial for moral development and moral behavior. However it is not known which specific brain areas contribute to the process of judging morally in the intact human brain. Our aim was therefore to identify brain areas involved in processing moral judgments. We presented subjects with blocks of sentences. Prior to each block the subjects were instructed to judge whether the sentences were morally (MJ) or semantically (SJ) correct or not. Answers were given by mouse-click and response-times were recorded. FMRI-data (1.5 T, 220 volumes, 30 3mm axial slices, 3 mm in plane resolution) were acquired in temporal asynchrony to the task. Response-times were slightly longer for SJ. MJ compared to SJ resulted in activation of the Gyrus angularis (BA 39) and superior temporal gyrus (BA 22) on the left side and the lateral orbitofrontal cortex (lOFC, BA 47) bilaterally. Our data are in line with recent reports showing a) that the right lOFC is also responsive to angry faces, which in moral or social contexts might serve as a signal to inhibit the current choice of behavior and b) that patients with adulthood-acquired ventromedial orbitofrontal lesions show disrupted social behavior while maintaining factual knowledge of social conventions and moral rules.