 While the egoism/altruism debate has historically been of great philosophical interest, the issue centrally concerns psychological questions about the nature of human motivation, so it’s no surprise that psychologists have done a great deal of empirical research aimed at determining which view is correct. The psychological literature will be center-stage in  section 5,  the longest section in this entry, and in  section 6.  But before considering the empirical literature, it is important to be clear  on what the debate is about.