Those who were pre-programmed to think in terms of having power “had a stronger preference for the rule-based more considerations, compared to participants in the low-power condition, who had a stronger preference for the outcome-based moral considerations.”
The researchers did find one exception to this pattern. In a final test, which was constructed so that rule-based thinking would not work to the advantage of the powerful, participants in the high-power category were less inclined than their low-power counterparts to endorse playing by the rules. Self-interest apparently trumps abstract ethical concepts.
That all makes sense—the powerful endorse rules for others because they’re a means to maintaining the order that preserves their power and yet make exceptions for themselves whereas the disempowered fear getting in trouble because of an unbending rule and so are more likely to appreciate the need for flexibility in complicated situations. But they’re also not as cavalier about bending rules for self-interest as those who see themselves as powerful.
Lammers and Stapel put it more delicately, noting that “rule-based thinking is attractive to the powerful because stability is in their interest and, therefore, cognitively appealing.” They also call attention to previous research suggesting powerful people tend to focus on the big picture rather than small details (which some researchers believe is one reason they successfully move up the ladder). This predisposition could presumably lead them to favor a stable, rule-based system over one that makes exceptions.
That all sounds quite plausible to me intuitively, at least.