Reaction Paper

Reaction Paper 1 (Sample Reaction Paper)

Ron Gerrard, HWS Psychology Department

My paper is based on an article from the text’s web site (chapter 9) entitled “Lack of sleep ages body’s systems.” The basic claim of the article is that sleep deprivation has various harmful effects on the body. The reported effects include decreased ability to metabolize glucose (similar to what occurs in diabetes) and increased levels of cortisol (a stress hormone involved in memory and regulation of blood sugar levels). The article also briefly alludes (in the quote at the bottom of page 1) to unspecified changes in brain and immune functioning with sleep deprivation.

Intuitively, these results make a lot of sense to me. I know that when I’m sleep deprived for any significannot

amount of time, I begin to feel physically miserable. I also seem to be more vulnerable to colds and other physical ailments. In thinking about it though, most of the times I’m sleep deprived are also periods of psychological stress (such as finals week). To the extent that there are changes in my physical well-being, I’m wondering whether they are due to the sleep deprivation, the stress itself, or some combination of the two.

In principle, a careful experiment should be able to isolate the effects of sleep deprivation by depriving people of sleep in the absence of stress and other such confounding variables. That seems to be what this experiment does, but as I read the article closely, I found myself unsure that the effects it reports are necessarily due to sleep deprivation per se.

I realize that a brief summary article like this does not provide all the details of the experimental methodology, but a couple of things that were reported in the article struck me as curious. The researchers studied physical functioning (cortisol levels, etc.) in men who had a normal night’s sleep (eight hours in bed) the first three nights of the study, followed by a period of sleep deprivation (four hours in bed) the next six nights of the study, and finally a period of sleep recovery (12 hours in bed) the last seven nights of the study. In reporting the effects on the body (the discussion of glucose metabolism, in the fifth paragraph of the article) the author’s compare the sleep deprivation stage only to the sleep recovery stage, not to normal sleep. This seems to me like doing an experiment on drunkenness and comparing the drunk stage to the hangover stage, without ever reporting what happens when the person is sober. Since normal sleep would seem to be the appropriate control condition here, the absence of results from that condition makes me wonder if something unusual was found there and not reported in the article.

Another potential problem comes from the sequential nature of the different sleep conditions. All participants had normal sleep, then sleep deprivation, then sleep recovery (in that order). Therefore, the three conditions differ not only in the amount of sleep, but also in the level of familiarity with the experimental procedures. Why should that make a difference? Well, consider the results reported for the stress hormone cortisol. In comparing people who are sleep deprived (days 4-9 of the study) with those who are in sleep recovery (days 10-16 of the study), they are comparing people early in the experiment to those later in the experiment. If the experimental procedures are themselves stressful (e.g. drawing a blood sample) then a person who has been through it more often might find it less stressful, and therefore not respond so strongly. This fact, rather than the amount of sleep itself, might explain the pattern of results in the physiological data.

I’m not sure whether the methodological issues I’ve raised really do account for all the study’s results, but they should be corrected in future research on sleep deprivation. The easiest way to do this, it seems to me, would be to simply compare two different groups of participants, randomly assigned to either a normal sleep condition or a sleep deprivation condition. Each participant would be in his/her respective condition throughout the experiment, so there would not be any difference in general experimental familiarity that could account for differences between the two groups.

Assuming the results of the experiment can be confirmed, and that sleep deprivation really does have the physiological effects described, there is one other thing I find interesting about the study. This is the possible relationship of the results to aging. The article claims that the physiological changes associated with sleep deprivation are similar to those in the elderly. Since I remember from the textbook that the elderly sleep less than younger adults (who in turn sleep less than children) I’m wondering