A Guide To Becoming Literate In The Science Of Sex
June 10, 2015 by Justin Lehmiller
Although sex is a topic about which many of us are inherently curious, there are surprisingly few reliable sources out there for learning about it, especially sources that are grounded in scientific research instead of arbitrary notions of sexual morality. That is precisely the reason I started this blog in the first place. However, in order to get the most out of the sex research I share on this site (not to mention the research you might come across elsewhere in the media), it is vital that you first become literate in the science of sex. That is, it is important to understand and appreciate what sex research can and cannot tell us. To that end, below are six things you should keep in mind any time you sit down to read the latest write-up of sex research.
1.) There is no such thing as a “perfect” sex study—every study has some limitations. The nature and severity of the limitations will obviously vary a lot across studies, but they’re always there. Oftentimes, there is a concern about the size or representativeness of the sample (see #2 below for more on this), but there may also be concerns about the nature or design of the study’s procedures (e.g., Were the right outcome variables measured? Was there an appropriate control condition?). Either way, these limitations should give us pause in drawing sweeping conclusions based upon the findings of any given study. To that end, I always try to highlight at least some limitations of the studies I cover, but not all sex writers are as careful about this (indeed, research has found that it’s rare for media reports of scientific research to mention any limitations at all!). Be very wary of articles that discuss sex research, but make no mention whatsoever of limitations.
2.) Sex studies do not often have representative samples, so we must be very cautious in generalizing results. Representative samples are hard to come by in any line of research, but this is especially true in sex research for a couple of reasons. One is that sex research is very underfunded, and without significant sums of money, it is challenging to recruit large and demographically representative samples. However, even when sex studies are funded, we run into issues with nonresponse and self-selection. In other words, not everyone wants to participate in sex studies, especially those that involve hooking gadgets up to one’s genitals. The end result is that volunteers for sex studies frequently hold more positive attitudes about sex and are more sexually experienced than the rest of the population . Likewise, studies of sexual minorities tend to oversample those who are more comfortable and confident in their sexuality. In light of this, it is important to always pay attention to the nature of the sample and how participants were recruited, and also to ask yourself “to whom do these results apply?” Be wary of sex research reports that don’t tell you anything about the sample or that seem to make overly broad generalizations.
3.) Correlational studies tell us nothing about cause-and-effect. Correlational studies are common in sex research, in which scientists look to see which variables are statistically associated. For instance, a correlation analysis could tell us whether there’s a link between condom use and women’s mood states—and, indeed, at least one study has found support for this idea, such that women who use condoms more frequently tend to report being less happy . Trying to draw conclusions about what associations like this mean can get us into real trouble, though, because correlations don’t tell us why any two variables are linked. Does condom use really cause changes in women’s mood, or do women’s mood states influence their condom use habits? Or is there perhaps a third variable (e.g., relationship quality or length) that instead accounts for this association? For this reason, it is important to be cautious when it comes to interpreting correlational studies and to avoid buying into media reports that “hype” and sensationalize correlations (see here and here for a few particularly bad examples of media reports featuring correlational sex research).
4.) “Average” is not synonymous with “normal.” “Normal” represents a wide range of responses. Media reports of sex research often report statistical averages from studies (e.g., average penis size, average sexual frequency, etc.). Unfortunately, many readers have a tendency to assume that those averages are a reflection of what is “normal.” However, it is important to keep in mind that what is “normal” is never a single number—it is always a range of responses. Thus, you should avoid thinking that just because you don’t match up exactly with some average that you’re somehow “abnormal.” Averages can be misleading in other ways, too, which you can read more about in this article.
5.) There are no universal principles of human sexuality—there are always exceptions to the “rules.” I have seen many journalists leap to conclusions about how “men are like ___, while women are like ____” in write-ups of sex studies. Such conclusions are inaccurate, though, because I have never seen a sex study in which all people of a given group responded in exactly the same way—there is always some degree of variability present. Research can only tell us what certain groups of people do on average, not what everyone in a given group does. It is important to avoid stereotyping group members in everyday life based solely on the group averages you’ve read about in a research report.
6.) A write-up of the latest sex study is not necessarily an invitation to change your life. Although many sex writers have a tendency to tell you what every study can do for you or how you can apply the results to your own life, I don’t do this very often, and it’s because of all the reasons I outlined above. It is often difficult (if not impossible) to make practical recommendations given the limitations of the study and sample, and this is especially true when the research is correlational. In addition, we know that not every study will replicate for a variety of reasons (e.g., a given finding could potentially be a false positive), and it’s not uncommon for two studies to come out around the same time showing opposite or contradictory effects. In light of this, you should not look at every study through the lens of “what can I personally do with these results?” When it comes to applying science to your own life, it’s important not to just look at single studies, but to look at the broader literature in a given area and to give due consideration to the limitations of the research.
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 Plaud, J.J., Gaither, G.A., Hegstad, H.J., Rowan, L., & Devitt, M.K. (1999). Volunteer bias in human psychophysiological sexual research: To whom do our research results apply? Journal of Sex Research, 36, 171-179.
 Gallup, G
. G., Burch, R. L., & Platek, S. M. (2002). Does semen have antidepressant properties? Archives of Sexual Behavior, 31, 289-293.
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Dr. Justin LehmillerFounder & Owner of Sex and Psychology
Dr. Justin Lehmiller is a social psychologist and Research Fellow at The Kinsey Institute. He runs the Sex and Psychology blog and podcast and is author of the popular book Tell Me What You Want. Dr. Lehmiller is an award-winning educator, and a prolific researcher who has published more than 50 academic works.Read full bio >