Paul Wright PhD is a highly regarded, prolific pornography researcher. Apparently, he’s tired – as are many others in this field – of the deceptive tactics employed by some of the notoriously agenda-driven sexology researchers in the field (and their biased refereeing of papers). He highlights two of their stratagems in separate Letters to the Editor of Archives of Sexual Behavior, and recommends both stratagems be discouraged going forward.
“Causation doesn’t equal correlation” (Oh please)
Sexologists often attempt to persuade journalists (and anyone else who will listen) that all of the formal evidence about porn’s effects is merely “correlational” and therefore meaningless. In fact, there’s now plenty of evidence suggesting that porn use causes harms, and Wright skillfully makes this point in his second Letter to the Editor, “Pornographic Socialization as “Selective-Exposure”: Let it Go, Let it Go II.” It’s time for journalists to seek out experts like Wright, who regularly analyze the relevant research, instead of relying on vocal, agenda-driven sexologists.
Wright points out that the sexologists’ lobbying means that academic authors who research porn’s effects feel that they must deny any possibility that porn use likely causes the behaviors, beliefs or attitudes the researchers discover are associated with its use. Often these tired disclaimers are so incongruous with the papers’ findings that its evident that the sexologists reviewing the papers demanded them.*
Worse yet, we can add that biased editors on Wikipedia (such as the notorious Tgeorgescu) and their sexology allies, create echo-chambers for this cherished talking point that “Correlation does not equal causation.” In fact, they use variations of it to self-righteously exclude research demonstrating porn’s harmful effects from the relevant Wikipedia pages – even as they permit the addition of cherry-picked pro-porn correlational research!
So, are the researchers who investigate porn-associated harms wise to appease their sexology-overlord reviewers by declaring that causation remains a complete mystery? Read on.
As Wright points out, it’s the old “the chicken or egg” issue. Which came first: the porn use (X), or the belief, attitude or behavior being assessed (Y)?
As any reader even casually familiar with the discussion sections of pornography effects papers utilizing cross-sectional data knows, it is a virtual guarantee that the authors will caution [or be obliged to caution] that any association they found between pornography use (X) and the belief, attitude, or behavior under study (Y) may be due to “selective-exposure” (i.e., people already in possession of the belief, attitude, or behavioral pattern gravitating to sexual media content that depicts it) not sexual socialization (i.e., people being influenced by the sexual media content in the direction of the belief, attitude, or behavior).
- Did pre-existing sexist beliefs lead to [cause] greater porn use (“selective-exposure”), or did greater porn use induce [cause] sexist beliefs (“sexual socialization”)?
- Did addiction-related brain changes lead to greater porn use, or did chronic porn use induce brain changes that mirror those seen in drug addicts?
- Did sexual aggression lead to greater porn use at some imaginary point in the future, or did regular porn use increase likelihood of sexual aggression?
- Does porn use lead to poorer relationship satisfaction, or does relationship dissatisfaction lead to porn use?
Wright points to decades of research suggesting a likelihood that porn actually causes harmful effects, including dozens of studies following subjects over time (longitudinal). Yet authors obsequiously continue to yield to the demands of their sexology-overlord reviewers:
In other words, the authors will adopt the stance that despite the pages of conceptual and theoretical arguments they devoted to justifying a X → Y dynamic in their literature review section, it is just as likely the case that Y → X. The author will then call for “longitudinal research” to “untangle” the directionality of the relationship. A review of discussion sections from years and years ago to the present day reveals that it is “always true” that cross-sectional pornography–outcome associations are just as likely due to selective-exposure as sexual socialization; this “never changes,” to quote Anna.
Wright appears to view this practice as an abuse of the scientific literature. In fact, he says it is “antithetical to science” to claim that directionality/causality remains a mystery in the porn field:
This is, of course, antithetical to science. Nothing is “always true” in science, because scientific knowledge “changes” as new knowledge is generated.
As Wright explains in detail, the “new knowledge generated” includes multiple “cross-lagged” longitudinal studies using panel data to compare directly X → Y and Y → X explanations for the directionality of the XY relationship. He writes:
Having published a number of cross-lagged longitudinal papers finding evidence for sexual socialization but not selective-exposure, I know that there are such studies.
In this Letter to the Editor of Archives of Sexual Behavior he analyzed 25 relevant (cross-lagged) longitudinal porn studies suggesting directionality (i.e., likelihood of causality). Fourteen found that earlier pornography use predicted one or more of the later outcomes studied, but the converse was not the case (i.e., prior levels of the outcome or outcomes did not predict later use of pornography). Ten studies found a reciprocal relationship. That is, prior propensities resulted in some people being more likely to consume pornography than others and these people were also subsequently impacted by their exposure. One study (by RealYBOP member Stulhofer) claimed prior propensities predicted porn use, but its overall correlation pattern suggested either reciprocal influence or no influence in either direction. He also notes that multiple (criterion variable) longitudinal panel studies suggesting directionality (i.e., likelihood of causality) have found significant pornography → outcome associations, after accounting for earlier levels of the outcome.
Wright sums up the state of the research (and the misuse of caveats):
In sum, the notion that significant correlations between pornography use and beliefs, attitudes, and behaviors in cross-sectional studies could be due entirely to selective-exposure is in contradiction to the accumulated evidence and could only be supported by a philosophy espousing that science is noncumulative and each study is an isolated fragment that stands entirely on its own; that scientists must start from scratch with each study–they cannot build on the prior body of knowledge; and that science is not open to modification–regardless of the passage of time and new evidence, ways of thinking about a phenomenon should not be revised.
For the curious and the scholarly he includes two helpful tables listing all of the 39 longitudinal studies he analyzed.
It is clear Wright thinks it is irresponsible for sexology researchers and reviewers/editors to keep insisting on their cherished mantra that porn isn’t causing effects on some users. In fact, here are his candid recommendations to authors, editors and reviewers to stop this deceptive nonsense. His recommendations are so masterful that we include them verbatim:
Authors: Do not state that selective-exposure is an equally plausible alternative explanation for your findings. If reviewers and editors demand you do, provide them with this Letter. If they still demand it, write the obligatory-to-be-published “limitation” statement in a way that absolves you personally from this uninformed opinion and reference this Letter.
Reviewers: Do not ask authors to state that selective exposure is an equally plausible alternative explanation for their results unless you can articulate specifically why their data and findings are such a special and novel case that the accumulated evidence to the contrary is inapplicable. Given the state of the literature, the onus is on you to delineate why the pornographic socialization the authors describe is really just selective-exposure. If the authors make the statement themselves, suggest they remove it and direct them to this Letter.
Editors: Overrule uninformed reviewers who demand that authors make the selective-exposure caveat. Notify authors of this Letter and suggest that while a case for a reciprocal dynamic can be made, a case for selective exposure only is untenable given the state of the literature at present.
Stop overcontrolling for extraneous variables that veil unwanted results (1st Letter)
The universal question: “Why do some studies counter the majority of published studies and report no correlation between porn use and a particular negative outcome (e.g. sexist attitudes)?” There are lots of reasons, but Paul Wright took aim at one often employed by certain porn researchers: overcontrolling for extraneous variables.
Most of us are familiar with simple, straightforward correlations such as frequency of porn use correlating with relationship dissatisfaction. But these days many studies on the effects of porn add in questionable additional variables (often to minimize or obfuscate findings).
Employing variables to downplay obvious correlations is called an “Everest regression.” The Everest Regression is what happens when you “control” for a fundamental variable when comparing two populations. For example, after controlling for height, Mount Everest is room temperature. Or, after controlling for bone-length, men aren’t taller than women.
In short, you use a model that removes a critical property of a phenomenon, and then go on to make confusing/misleading inferences about it. Porn studies by sexologists often employ this ruse to obfuscate findings that place porn in a negative light.
So, let’s examine Wright’s second letter “Overcontrol in Pornography Research: Let it Go, Let it Go….”
In this Letter to the Editor it he calls out 3 of the most infamous pro-porn researchers, Kohut, Landriput and Stulhofer. These guys use this deplorable tactic of overcontrolling for everything they can think of (with no theoretical basis) until they can eradicate results they don’t care for – and produce titles better suited to their propaganda-efforts-posing-as-responsible-research.
In “Testing the confluence model of the association between pornography use and male sexual aggression: A longitudinal assessment in two independent adolescent samples from Croatia),” Kohut, Landriput and Stulhofer claimed that their overcontrolling tactics made their study superior to one done by Wright and colleagues. The Wright & colleagues study found that porn use was a robust predictor of both verbal and physical sexual aggression (“A meta-analysis of pornography consumption and actual acts of sexual aggression in general-population studies“).
Kohut, Landriput and Stulhofer didn’t like that result, and would have the public and gullible journalists believe that more “control variables” must be properly accounted for…until, magically, the use of today’s porn (which is rife with violent, abusive behavior) is no longer associated with sexual aggression. Wright points out that many respected researchers disagree with the K, L & S assertion that “more control variables make research better.” One calls it a “methodological urban legend.”
Wright, who has conducted numerous reviews of the literature, explains:
Through such literature syntheses I have observed that (1) the vast majority of pornography effects studies from the 1990s on have been conducted using survey methods and (2) the predominate analytical paradigm in this body of research is to ask if pornography use (X) is still correlated with some belief, attitude, or behavior (Y) after statistically adjusting for an ever increasing and ever more peculiar list of “control” variables (Z ad infinitum).
Here are just a few examples of variables that researchers have deemed necessary to include as controls: sexual experience, pubertal status, age, relationship status, sexual orientation, gender, education, socioeconomic status, race, perceptions of religious texts, emotional connectedness with caregiver, exposure to spousal violence, substance use, marital status, political affiliation, hours of work in a week, parents’ marital status, sex drive, ethnic identity, antisociality, depression symptoms, PTSD symptoms, relationship satisfaction, peer attachment, sex talk with peers, attachment to parents, television viewing, parental control,perceived sexual experience of peers, sensation seeking, sexual sensation seeking, life satisfaction, family background, sexual self-esteem, sexual assertiveness, attitudes toward sexual coercion, age of friends, social integration, internet use, music video viewing, religious affiliation, relationship length, immigrant background, living in a large city, parental employment, smoking, history of theft, truancy, conduct problems at school, age of sexual debut, dating activity, telling lies, cheating on tests, social comparison orientation, geographical location of residence, masturbation frequency, religious service attendance, sexual satisfaction, satisfaction with decision making, number of children, ever divorced, employment status, number of religious friends, frequency of sex in the past week, and enrollment in a postsecondary school.
Again–these are just a few examples.
The inclusion of control variables does not lead to more accurate conclusions about the nature of an X → Y association under investigation. In fact, it is likely to produce pseudo-falsifications. In short, there is nothing conservative or rigorous about including additional statistical controls. In many cases it is quite deceptive. Wright continues:
The (ostensible) logic underlying the current approach is that pornography may not be an actual source of social influence; rather, some third-variable may cause individuals to both consume pornography and express/engage in the belief, attitude, or behavior in question. Few authors, however, explicitly identify how each variable they selected as a control could cause both pornography consumption and the outcome being studied. Sometimes, a general statement is made (sometimes with citations, sometimes without) that prior research has identified the variables as potential confounds and this is why they are included. Other times, no explanation is offered other than to list the various control variables. It is very difficult to find studies that identify a specific theoretical perspective as justifying the selection of controls (more on this point later). It is even rarer to find a study that justifies why the variables were modeled as controls rather than predictors, mediators, or moderators (I don’t believe I’ve ever seen this).
The academic sources Wright cites note that the “purification principle” (of controlling for additional random variables) can cause the abandonment of sound theories. Says Wright:
When the pornography effects research landscape is considered in totality, it is my contention that the inclusion of controls is idiosyncratic, inconsistent, atheoretical, and overdone. My best guess is that researchers either include controls because prior researchers have, they believe editors or reviewers will expect it (Bernerth & Aguinis, 2016), or because they have fallen victim to the “methodological urban legend” that “relationships with control variables are closer to the truth than without control variables.”
Of course, some of us believe Kohut, Landriput and Stulhofer are indeed intentionally seeking to cast doubt on the established link between porn use and ill effects (Kohut & Stulhofer joined allies Nicole Prause and David Ley as experts on the porn-shill site RealYourBrainOnPorn.com). They regularly publish outlier studies which, remarkably, find virtually no problems with porn use. Then, the porn industry and its allies loudly publicize such outlier results with the help of susceptible journalists and Wikipedia, while ignoring the preponderance of the evidence by more objective researchers.
Wright convincingly, but politely, takes Kohut, Landriput and Stulhofer to task for their contemptible little game. He recommends that pornography researchers treat third-variables as predictors (i.e., factors that differentiate the frequency and type of pornography consumed). Or as mediators (i.e., mechanisms carrying the effects of pornography). Or as moderators (elements of people and contexts that either inhibit or facilitate the effects of pornography). But he calls on them to stop treating these random associations as “confounds” extraneous to, and contaminant of, the effects of pornography on beliefs, attitudes, and behaviors.
Interestingly, Wright gives examples (and citations) of factors that appear to be inappropriate to control for because there is evidence that they are part of the pornography effects process. Don’t miss his comments on the inappropriateness of controlling for religiosity, “preexisting” sexual attitudes, and sensation-seeking.
With respect to sensation-seeking, for example, Wright points out that research demonstrates that porn use may predict later sensation-seeking, and not the reverse:
Sensation seeking has also been conceptualized as an immutable trait that could only confound pornography–outcome correlations. The taken-for-granted narrative is that sensation seeking could affect pornography consumption and (insert sexual risk outcome here) and therefore be a confound, but could not be impacted by pornography consumption. The empirical record suggests otherwise, however. In the realm of sexual media in general, Stoolmiller, Gerrard, Sargent, Worth, and Gibbons (2010) found in their four-wave, multiple year longitudinal study of adolescents that R-rated movie viewing predicted later sensation seeking, while earlier sensation seeking did not predict later R-rated movie viewing. Stoolmiller et al. note that their results “provide empirical evidence of an environmental media effect on sensation seeking.
Thus, viewing sexual content resulted in greater sensation-seeking (not the other way around). Wright continues, pointing out the path of causation: Porn use >>> sensation-seeking >>> risky sexual behavior:
Subsequent analyses of these data focusing on sexual content specifically found that sexual content exposure predicted increases in sensation seeking, which in turn predicted risky sexual behavior (O’Hara, Gibbons, Gerrard, Li, & Sargent, 2012).
Yet a pro-porn researcher might spin these data to suggest that sensation-seeking causes risky sexual behavior, with porn use being an afterthought.
Finally, in his Recommendations section, Wright takes aim at the extreme bias of some pro-porn researchers:
If we are honest with ourselves, we must acknowledge that our studies proceed from certain assumptions that can never be irrefutably confirmed or falsified to the satisfaction of 100% of scholars. I was born in 1979. There were social scientists who believed pornography could not affect its users before I was born and I guarantee there will be social scientists when I’m gone (hopefully, at least another forty or so years) who will believe the same.
While it is an existential possibility that pornography is the lone communicative domain where messages and meanings have zero impact, and that any correlation between pornography use and beliefs, attitudes, and behaviors is always spurious and due entirely to some other independent and immutable causal agent, I believe there is sufficient theoretical reasoning and empirical evidence to assume that this is not the case. Accordingly, I [ask] my colleagues to “turn away and slam the door” on the “does pornography still predict (outcome) after controlling for the kitchen sink?” approach. Instead, I ask that we direct our attention to third variables that differentiate the frequency and type of pornography consumed, the mechanisms that lead to particular outcomes, and the people and contexts for whom those outcomes are more or less likely.
Finally, some long overdue chlorine has been added to the porn-research pool!
Thank you to Paul Wright for his courage in calling out some of the scummier tactics in the field of porn research. We hope that other researchers will take his recommendations to heart and push back against the sexology bullies who dominate the field of porn research with their extreme biases and strategy of rejecting or hopelessly watering-down research they don’t like.
Keep in mind that there has long been a cozy relationship between sexologists and Big Porn. Disturbing.
* Here’s a typical porn-apologist researcher desperately clinging to his cherished assumption that porn can’t be the cause of problems, and insisting that nobody better dare say otherwise! How objective do you think this man could be when reviewing porn research?? Does he also think alcoholism researchers should focus on the relationship between drinking and pleasure, not on the adverse effects of drinking?
For future research, we note that researchers must be scrupulous not to conflate correlation and causality when discussing the relationship between aspects of HSD [healthy sexual development…as he defines it] and the consumption of pornography. We encourage researchers to focus on the relationship between pornography consumption and sexual pleasure – this is a vital part of HSD.
Or check out this condescending drivel tweeted by an infamous porn shill sexologist:
Research methods 101: Cross-sectional data cannot demonstrate cause.
Um…Research methods 201: Longitudinal data can strongly suggest cause.