My last post about Boss Poop  and the dozens of examples that people posted about Clueless and Comical Bosses  (I will post a top 11 list later this week) provide cautionary tales that every person who wields power over others ought to pay attention to--because that clueless boss could be you. As I have shown here and in Good Boss, Bad Boss, there is extensive and scary evidence that these stories reflect a tendency for people who oversee others, or who simply feel as if they have power, to become more concerned about their own needs, less concerned about the needs of others, to act like the rules don't apply to them, and a host of other rather scary effects (although not all are bad... for example, power makes people more action oriented, which can be a good thing).
A new study--actually a series of intertwined experiments--just came out (and was summarized by our friends at BPS Research ) that adds to the pile of evidence about power poisoning. In short, this research  shows that when people have power over others, or simply think about a time when they were powerful or role play being powerful, they tend to dehumanize others. The third of the three studies in this article is summarized by BPS as follows:
In a final study, Lammers and Stapel had 50 student participants role-play the position of senior surgeon, junior surgeon or nurse before making a treatment decision about their fictional patient - a 56-year-old man with an abdominal growth. Those participants role-playing a more powerful position were more likely to opt for the painful but more effective of two treatment options. Moreover, the participants role-playing the senior surgeon role were more likely to show evidence of dehumanising the patient in a 'mechanistic' fashion - that is, rating him as more passive and less sensitive. The association between seniority of role and dehumanising was largely mediated by the decision to opt for the more painful treatment.
See the link  to read the rest of the summary. The authors emphasize that there are times when dehumanizing people isn't all bad because it can lead people in power to make "tough" decisions in a more rational fashion. But as I said at the outset, this is just one more indication that a little power can be a very dangerous thing.
P.S. A note in the spirit of evidence-based management. This is just one little article that summarizes three studies, and yes it is artificial and does not measure what happens in real workplaces. So like all research should not be taken as conclusive or the final word. But it is interesting because adds it just one more twist to the pile of evidence of power poisoning.
Here is the citation:
Lammers, J., and Stapel, D. (2010). Power increases dehumanization. Group Processes and Intergroup Relations DOI: 10.1177/1368430210370042 
Reprinted from Work Matters 
Robert I. Sutton, PhD is Professor of Management Science and Engineering at Stanford. His latest book is Good Boss, Bad Boss: How to Be the Best...and Survive the Worst . His previous book is The New York Times bestseller The No Asshole Rule: Building a Civilized Workplace and Surviving One That Isn't . Follow him at twitter.com/work_matters .