...possessing power itself serves as an impediment to understanding the perspectives of others. Through several studies, the researchers assessed the effect of power on perspective taking, adjusting to another's perspective, and interpreting the emotions of others.
This is not exactly surprising. For example, critical psychologists have noticed that many stereotypically "female" traits or skills, such as empathy, caregiving, nonviolence, and nurturing, are due to power differentials rather than biology. In other words, groups in subordinate social positions learn these skills for survival. I think it has something to do with being able to read those who hold more power; for example, anticipating their needs could lead to better rewards.
The abstract of the study reports:
Four experiments and a correlational study explored the relationship between power and perspective taking. In Experiment 1, participants primed with high power were more likely than those primed with low power to draw an E on their forehead in a self-oriented direction, demonstrating less of an inclination to spontaneously adopt another person's visual perspective. In Experiments 2a and 2b, high-power participants were less likely than low-power participants to take into account that other people did not possess their privileged knowledge, a result suggesting that power leads individuals to anchor too heavily on their own vantage point, insufficiently adjusting to others' perspectives. In Experiment 3, high-power participants were less accurate than control participants in determining other people's emotion expressions; these results suggest a power-induced impediment to experiencing empathy. An additional study found a negative relationship between individual difference measures of power and perspective taking. Across these studies, power was associated with a reduced tendency to comprehend how other people see, think, and feel. (emphasis mine)
Other interesting related links:
What can the Stanford prison and Milgram experiments tell us about abuses at Abu Ghraib and Creating Gender Role Behavior: Demonstrating the Impact of Power Differentials