Bob Sutton reports some intriguing research which appears to support the notion that power corrupts. Two groups of people were given alternative preparatory tasks. One group were asked to think of a time when they had power over others; the second group had to think of a time when others had power over them. Then both groups were asked to paint a letter E on their forehead.
The first group were strongly inclined to draw the letter so it looked right to them in a mirror; the second group were more likely to draw it so it looked write to others but wrong to them in the mirror. Bob writes about other similar research here.