An article last year in Psychological Science by Alia J. Crum and Ellen J. Langer, Mind-Set Matters: Exercise and the Placebo Effect, laid out an extremely interesting example of ‘top-down’ culturo-psycho-physiological dynamics in the body from my favorite area of research: exercise and sports. Crum and Langer looked at a group of 84 hotel room keepers. From the abstract:
Those in the informed condition were told that the work they do (cleaning hotel rooms) is good exercise and satisfies the Surgeon General’s recommendations for an active lifestyle. Examples of how their work was exercise were provided. Subjects in the control group were not given this information. Although actual behavior did not change, 4 weeks after the intervention, the informed group perceived themselves to be getting significantly more exercise than before.
If this were the only finding, there wouldn’t be too much news here. But the change in understanding of what they were doing also had physical effects on the room attendants, including, in addition to changed impressions, an average weight loss of 2 pounds, decrease in systolic blood pressure of 10 points, and positive effects on body mass and heart rates — in only 4 weeks with NO change in the actual activity level. Becoming convinced that they were getting enough exercise or engaged in adequate activity to promote health helped their background activity to affect their physiology. Exercise was not just a physical activity, it was also a state of mind (more accurately, without the ‘state of mind’ activity didn’t have the effects of ‘exercise’). (This research is also discussed in an article in The New York Times.)
As the researchers explain, ‘Conventional science assumes that in order for weight to be lost and body fat to be reduced, certain biological and physiological events must also take place.’ They argue that it is clear that ‘mind-set’ affects health: ‘The results of this study provide another example of the power of the placebo effect.’ They call for more research into the efficaciousness of placebos because they are inert, but they do little to move beyond this to talk about how they might work or the implications of ‘placebo’ effects of exercise awareness.
I like lots of things about this research and this article, but I don’t like the term, ‘placebo effect.’ As Crum and Langer explain, their research differs from typical research on ‘placebos’:
This study did not test the placebo effect in the traditional manner, in which expectations are aroused through inert pills or sham procedures. Rather, subjects were actually engaging in a behavior that is clinically proven to have positive effects on the physiological variables measured … To determine if the placebo effect plays a role in the benefits of exercise, this study investigated whether subjects’ mind-set (in this case, their perceived levels of exercise) could inhibit or enhance the health benefits of exercise independently of actual exercise.
The ‘effect’ they are describing is not so much a ‘placebo’ (belief in a nonactive agent causing effects) as the opposite; the failure to believe in ‘efficacious’ intervention neutralizes its effect. ‘Exercise’ requires the presence of some psychological component to have the level of effect that is expected.
Interestingly, the health of the room attendants reflected their perceived levels of exercise rather than their actual levels: According to their initial physiological measures, the subjects were at risk with respect to BP [blood pressure], BMI [body mass index], percentage of body fat, and WHR—all important indicators of health.
That is, the room attendants were getting exercise, but without the awareness, this activity did not seem to have the same effect. In other words, without the psychological awareness or expectation of physiological change for their physical activity, the women’s bodies did not change. The article is written in a kind of ‘either x or y’ rhetoric (either the activity or the mind set caused the effects), but I’d suspect that the relationship is more complex between the two (not even including the possibility of feedback, as impressions affect other behaviour, such as diet or sense of well-being). Because this research is a pretty standard ‘subject v. control group,’ there’s very little space to explore the mechanisms are potential intermediate effects.
On a more cultural level, believing in the category of ‘exercise,’ and classifying one’s activities as ‘exercise’ may influence its effect upon the subject’s body. Thinking that one’s activity is ‘exercise’ is not just an individual psychological effect but also a cultural complex: the category of ‘exercise’ has to exist and a particular activity has to come to be classified in that category.
Crum, Alia J., and Ellen J. Langer. 2007. Mind-Set Matters: Exercise and the Placebo Effect. Psychological Science 18(2): 165–171.