That's a very interesting experiment, however, at least from how it's described in that article, I don't think it's anywhere rigiorus enough to draw any conclusions from.
> One possible explanation is that the process of learning about the amount of exercise they were already getting somehow changed the maids' behavior. But Langer says that her team surveyed both the women and their managers and found no indication that the maids had altered their routines in any way. She believes that the change can be explained only by the change in the women's mindset.
I think that they're too quick to dismiss a change in behavior. Simply asking someone (and their managers‽) if they did anything different this month than they did last month isn't a very reliable way to figure out if there were any subtle changes in behavior.
I don't know if they were expecting massive conscious changes, but I would be shocked if suddenly knowing that their daily routine is good for them didn't change some of the subconscious decisions they were making. Even just simple things like taking the stairs 10% more than they did before or how they decide when and how much to eat based on a certain level of hunger. You're still going to think "I took the stairs sometimes, but took the elevator when I needed it." or "I ate the same foods that I did before." but maybe you were taking smaller portions.
Basically what I'm trying to say is that it's very hard to draw hard quantitative conclusions from vague qualitative assessments.