Having spent quite a bit of time around the psychological literature – both academic and lay pieces alike – there are some words or phrases I can no longer read without an immediate, knee-jerk sense of skepticism arising in me, as if they taint everything that follows and precedes them. Included in this list are terms like bias, stereotype, discrimination, and, for the present purposes, fallacy. The reason these words elicit such skepticism on my end is due to the repeated failure of people using them to consistently produce high-quality work or convincing lines of reasoning. This is almost surely due to the perceived social stakes when such terms are being used: if you can make members of a particular group appear uniquely talented, victimized, or otherwise valuable, you can subsequently direct social support towards and away from various ends. When the goal of argumentation becomes persuasion, truth is not a necessary component and can be pushed aside. Importantly, the people engaged in such persuasive endeavors do not usually recognize they are treating information or arguments differently, contingent on how it suits their ends.
“Of course I’m being fair about this”
There are few areas of research that seem to engender as much conflict – philosophically and socially – as sex differences, and it is here those words appear regularly. As there are social reasons people might wish to emphasize or downplay sex differences, it has steadily become impossible for me to approach most of the writing I see on the topic with the assumption it is at least sort of unbiased. That’s not to say every paper is hopelessly mired in a particular worldview, rejecting all contrary data, mind you; just that I don’t expect them to reflect earnest examinations of the capital-T, truth. Speaking of which, a new paper by Maney (2016) recently crossed my desk; a the paper that concerns itself with how sex differences get reported and how they ought to be discussed. Maney (2016) appears to take a dim view of the research on sex differences in general and attempts to highlight some perceived fallacies of people’s understandings of them. Unfortunately, for someone trying and educate people about issues surrounding the sex difference literature, the paper does not come off as one written by someone possessing a uniquely deep knowledge of the topic.
The first fallacy Maney (2016) seeks to highlight is the idea that sexes form discrete groups. Her logic for explaining why this is not the case revolves around the idea that while the sexes do indeed differ to some degree on a number of traits, they also often overlap a great deal on them. Instead, Maney (2016) argues that we ought to not be asking whether the sexes differ on a given trait, but rather by how much they do. Indeed, she even puts the word ‘differences’ in quotes, suggesting that these ‘differences’ between sexes aren’t, in many cases, real. I like this brief section, as it highlights well why I have grown to distrust words like fallacy. Taking her points in reverse order, if one is interested in how much groups (in this case, sexes) differ, then one must have, at least implicitly, already answered the question as whether or not they do. After all, if the sexes did not differ, it would pointless to talk about the extent of those non-differences; there simply wouldn’t be variation. Second, I know of zero researchers whose primarily interest resides in answering the question of whether the sexes differ to the exclusion of the extent of those differences. As far as I’m aware, Maney (2016) seems to be condemning a strange class of imaginary researchers who are content to find that a difference exists and then never look into it further or provide more details. Finally, I see little value in noting that the sexes often overlap a great deal when it comes to explaining the areas in which they do not. In much the same way, if you were interested in understanding the differences between humans and chimpanzees, you are unlikely to get very far by noting that we share a great deal of genes in common. Simply put, you can’t explain differences with similarities. If one’s goal is to minimize the perception of differences, though, this would be a helpful move.
The second fallacy that Maney (2016) seeks to tackle is that idea that the cause of a sex differences in behavior can be attributed to differing brain structures. Her argument on this front is that it is logically invalid to do the following: (1) note that some brain structure between men and women differ, (2) note that this brain structure is related to a given behavior on which they also differ, and so (3) conclude that a sex difference in brain structure between men and women is responsible for that different behavior. Now while this argument is true within the rules of formal logic, it is clear that differences in brain structure will result in differences in behavior; the only way that idea could be false would be if brain structure was not connected to behavior, and I don’t know of anyone crazy enough to try and make that argument. The researchers engaging in the fallacy thus might not get the specifics right all the time, but their underlying approach is fine: if a difference exists in behavior (between sexes, species, or individuals), there will exist some corresponding structural differences in the brain. The tools we have for studying the matter are a far cry from perfect, making inquiry difficult, but that’s a different issue. Relatedly, then, noting that some formal bit of logic is invalid is assuredly not the same thing as demonstrating that a conclusion is incorrect or the general approach misguided. (Also worth noting is that the above validity issue stops being a problem when conclusions are probabilistic, rather than definitive.)
“Sorry, but it’s not logical to conclude his muscles might determine his strength”
The third fallacy Maney (2016) addresses is the idea that sex differences in the brain must be preprogrammed or fixed, attempting to dispel the notion that sex differences are rooted in biology and thus impervious to experience. In short, she is arguing against the idea of hard genetic determinism. Oddly enough, I have never met a single genetic determinist in person; in fact, I’ve never even read an article that advanced such an argument (though maybe I’ve just been unusually lucky…). As every writer on the subject I have come across has emphasized – often in great detail – the interactive nature of genes and environments in determining the direction of development, it again seems like Maney (2016) is attacking philosophical enemies that are more imagined than real. She could have, for instance, quoted researchers who made claims along the lines of, “trait X is biologically-determined and impervious to environmental inputs during development”; instead, it looks like everyone she cites for this fallacy is making a similar criticism of others, rather than anyone making the claims being criticized (though I did not check those references myself, so I’m not 100% there). Curiously, Maney (2016) doesn’t seem to be at all concerned about the people who, more-or-less, disregard the role of genetics or biology in understanding human behavior; at the very least she doesn’t devote any portion of her paper to addressing that particular fallacy. That rather glaring omission – coupled with what she does present – could leave one with the impression that she isn’t really trying to present a balanced view of the issue.
With those ostensibly fallacies out of the way, there are a few other claims worth mentioning in the paper. The first is that Maney (2016) seems to have a hard time reconciling the idea of sexual dimorphisms – traits that occur in one form typical of males and one typical of females – with the idea that the sexes overlap to varying degrees on many of them, such as height. While it’s true enough that you can’t tell someone’s sex for certain if you only know their height, that doesn’t mean you can’t make some good guesses that are liable to be right a lot more often than they’re wrong. Indeed, the only dimorphisms she mentions are the presence of sex chromosomes, external genitalia, and gonads and then continues to write as if these were of little to no consequence. Much like height, however, there couldn’t be selection for any physical sex differences if the sexes did not behave differently. Since behavior is controlled by the brain, physical differences between the sexes, like height and genitalia, are usually also indicative of some structural differences in the brain. This is the case whether the dimorphism is one of degree (like height) or kind (like chromosomes).
Returning to the main point, outside of these all-or-none traits, it is unclear what Maney (2016) would consider a genuine difference, much less any clear justification for that standard. For example, she notes some research that found a 90% overlap in interhemispheric connectivity between the male and female distributions, but then seems to imply that the corresponding 10% non-overlap does not reflect a ‘real’ sex difference. We would surely notice a 10% difference in other traits, like height, IQ, or number of fingers but, I suppose in the realm of the brain, 10% just doesn’t cut it.
Maney (2016) also seems to take an odd stance when it comes to explanations for these differences. In one instance, she writes about a study on multitasking that found a sex difference favoring men; a difference which, we are told, was explained by a ‘much larger difference in video game experience,’ rather than sex per se. Great, but what are we to make of that ‘much larger’ sex difference in video game experience? It would seem that that finding too requires an explanation, and one is not present. Perhaps video game experience is explained more by, I don’t know, competitiveness than sex, but then what are we to explain competitiveness with? These kinds of explanations usually end up going nowhere in a hurry unless they eventually land on some kind of adaptive endpoint, as once a trait’s reproductive value is explained, you don’t need to go any further. Unfortunately, Maney (2016) seems to oppose evolutionary explanations for sex differences, scolding those who propose ‘questionable’ functional or evolutionary explanations for sex differences for being genetic determinists who see no role for sociocultural influences. In her rush to condemn those genetic determinists (who, again, I have never met or read, apparently), Maney’s (2016) piece appears to fall victim to the warning laid out by Tinbergen (1963) several decades ago: rather than seeking to improve the shape and direction of evolutionary, functional analyses, Maney (2016) instead recommends that people simply avoid them altogether.
“Don’t ask people to think about these things; you’ll only hurt their unisex brains”
This is a real shame, as evolutionary theory is the only tool available for providing a deeper understanding of these sex differences (as well as our physical and psychological form more generally). Just as species will differ in morphology and behavior to the extent they have faced different adaptive problems, so too will the sexes within a species. By understanding the different challenges faced by the sexes historically, one can get a much clearer sense as to where psychological and physical difference will – and will not – be expected to exist, as well as why (this extra level of ‘why’ is important, as it allows you to better figure out where an analysis has gone wrong if the predictions don’t work). Maney (2016), it would seem, even missed a golden opportunity within her paper to explain to her readers that evolutionary explanations complement, rather than supplant, more proximate explanations when quoting an abstract that seemed to contrast the two. I suspect this opportunity was missed because she is either legitimately unaware of that point, or does not understand it (judging from the tone of her paper), believing (incorrectly) instead that evolutionary means genetic, and therefore immutable. If that is the case, it would be rather ironic for someone who does not seem to have much understanding of the evolutionary literature lecturing others on how it ought to be reported.
References: Maney, D. (2016). Perils and pitfalls of reporting sex differences. Philosophical Transactions B, 371, 1-11.
Tinbergen, N. (1964). On aims and methods of ethology. Zeitschrift für Tierpsychologie, 20, 410-433.