„Männer und Frauen sind von der Erde“

Eine Studie kommt zu dem Ergebnis, dass Männer und Frauen nicht von Mars und Venus sind, sondern von der Erde. Gemeint ist natürlich, dass die Unterschiede zwischen den Geschlechtern nicht so groß sind:

Taxometric methods enable determination of whether the latent structure of a construct is dimensional or taxonic (nonarbitrary categories). Although sex as a biological category is taxonic, psychological gender differences have not been examined in this way. The taxometric methods of mean above minus below a cut, maximum eigenvalue, and latent mode were used to investigate whether gender is taxonic or dimensional. Behavioral measures of stereotyped hobbies and physiological characteristics (physical strength, anthropometric measurements) were examined for validation purposes, and were taxonic by sex. Psychological indicators included sexuality and mating (sexual attitudes and behaviors, mate selectivity, sociosexual orientation), interpersonal orientation (empathy, relational-interdependent self-construal), gender-related dispositions (masculinity, femininity, care orientation, unmitigated communion, fear of success, science inclination, Big Five personality), and intimacy (intimacy prototypes and stages, social provisions, intimacy with best friend). Constructs were with few exceptions dimensional, speaking to Spence’s (1993) gender identity theory. Average differences between men and women are not under dispute, but the dimensionality of gender indicates that these differences are inappropriate for diagnosing gender-typical psychological variables on the basis of sex

Quelle: Men and Women Are From Earth: Examining the Latent Structure of Gender

Hier die Daten aus der Studie:

Nach dieser Studie also mittlere bis kleine Unterschiede.

Wie man an den Big Five sieht, werden hier teilweise Punkte zusammengeworfen, die in sich wieder starke Unterschiede in  beide Richtungen aufweisen, die sich dann im Endeffekt wieder ausgleichen.

Zur Kritik an der Studie:

Neuroskeptic schreibt:

Their argument is that psychological differences between the genders are, in most cases, not because „male“ and „female“ are two distinct taxons.

So what? I previously covered a paper called The Distance Between Mars and Venus claiming that the difference between men and women on average are larger than previously thought, if you look at all the differences taken together. That’s actually consistent with what Carothers and Reis are saying, I think, because it assumes that each of the differences is dimensional and quantitative.

In other words, maybe sexes differ only by a matter of degree, albeit by a larger degree than you’d think at first glance.

Den Artikel hatte ich auch hier besprochen.

In die gleiche Kerbe haut auch dieser weitere Artikel:

In a multivariate study by Del Giudice et al. (2012), men’s and women’s personalities were contrasted along 16 fundamental personality dimensions at the same time. By looking at all these dimensions simultaneously, researchers were able to control for the fact that many psychological dimensions overlap with one another. Because of this overlap, scientists cannot just add up all the differences between men and women, or just average across the differences for each psychological dimension. Instead, the most informative approach for evaluating the overall sex difference is to examine all the sex differences across multiple dimensions at the same time (whilst also controlling for all overlap among dimensions). It can be a bit tricky, but when they did this in the statistically appropriate manner, Del Giudice et al. found the sexes differed enormously, with only a 10% overlap in their overall personality distributions. Not Mars versus Venus exactly, but certainly not extreme gender similarity.

Carothers and Reis may have been well-intentioned, but many aspects of their study were conceptually weak and the conclusion of many media reports that men and women do not differ in their sexuality is empirically very wrong. Sexual science deserves better. Men and women show marked differences in many sexual attributes, particularly in sociosexual attitudes, short-term mating tendencies, and expressed mate preferences. This is some of what we know about important sex differences in sexual psychology, and a little bit about how we know it. To pretend otherwise is not only bad science, it can be risky for the sexual health of men and women everywhere.

Zu den methodischen Fehlern in dem gleichen Artikel:

Unfortunately, the study by Carothers and Reis makes some big mistakes, both conceptually and empirically. Not so great. Not so science. Here is why. Conceptually, it is ironic that a paper rooted in concerns about dichotomous thinking about sex differences—Mars versus Venus labeling—sets out to portray sex differences in a dichotomous manner, as either categorical or dimensional. Sex differences must be understood dichotomously, but men and women must not be? Such irony would be funny, if not for it also serving as a critical conceptual shortcoming. Psychological attributes are almost always multiply determined (even if influenced by genetic and hormonal factors related to biological sex). To imply that the sexes do not really differ on an attribute if they do not nearly entirely differ on that attribute is scientific nonsense (see an informative post by Michael Mills here). Life is more complicated than that, and Carothers and Reis do partially recognize this.

For instance, they note in their study that whether an attribute is dimensional or categorical, this does not tell us definitively about the origins of the sex difference (e.g., whether it is socially or biologically caused; or both in complex ways): “Our findings are silent with respect to the question of whether gender differences in the variables we studied are caused primarily by biological factors or experience (Eagly & Wood, 1999). In our view, both biological and social causes are essentially continuous, leading individuals to develop various proclivities and dispositions to one or another extent, and encouraging them to follow certain developmental pathways to a greater extent than others (Archer, 1984; Halpern, 2012; Maccoby, 2002). It is unlikely that any of these pathways are fully discrete.” Well said. I couldn’t agree more.

Die Studie berücksichtigt also nicht, dass es Überschneidungen durchaus geben kann.  Sie berücksichtigt insofern auch nicht, dass auch wenn die Streuung innerhalb der Geschlechter groß sein kann, die Unterschiede dennoch deutlich zu Tage treten können, weil die Verschiebung hoch ist und sich insbesondere in den jeweiligen Endbereichen zeigt. Wenn Männer mehr Idioten, aber auch mehr Genies stellen, dann ist der Unterschied zwischen den Geschlechtern in dem Bereich beispielsweise im Schnitt nicht so groß. Dennoch können dann beispielsweise mehr Spitzenforscher männlich sein.

Weitere Kritik aus dem Arikel:

So, what did the authors really find when it comes to sexuality? In evaluating pre-existing datasets, the authors combined multiple items (specific questions on sex surveys) and evaluated whether a dichotomous structure is formed by the differing responses of men and women. That is, they focused on whether men’s and women’s responses place them into two distinct sexual groups. More precisely, the researchers tested to see if when men scored higher than women on one sex question (e.g., willingness to have sex without love), were men also higher on than women on all other theoretically-similar sex questions? And did the responses cluster together so closely among men and so differently among women as to form a “taxon” (or a dichotomous category dependent mostly on biological sex)?

Empirically, this seems like a reasonable question. As addressed in the study, though, it is not. A huge problem with the study is, in most cases, the combined sexuality questions (questions the authors argued should form clusters dichotomously distinguished by biological sex) really should not be expected to cluster together as a taxon, especially from the theoretical perspective of evolutionary psychology.

Take their archival analysis of the National Health and Social Life Survey dataset (this is a large nationally representative sample of the USA in which some sexuality questions were asked). Some of the questions—such as the appeal of sex with more than one partner, the appeal of having sex with a stranger, and the willingness to have sex without love—should be reasonably expected to co-vary together. On their surface, all the items seem relevant to what evolutionary psychologists call “short-term mating psychology” or “unrestricted sociosexuality.” Even so, from an evolutionary perspective, these items should not co-vary entirely by sex.

As I have posted over and over again in this blog, evolutionary psychologists expect that only some men pursue short-term mating strategies (e.g., given their own mate value, physical attractiveness, attachment experiences, local pathogen levels, local sex ratios, and so forth; see Gangestad & Simpson, 2000). Not all men are short-term maters at all times. If this is the view that Carothers and Reis have of evolutionary psychology, it is an inaccurate one. And some women are also expected to strategically pursue short-term mating (albeit for different underlying functional reasons than men do). Thus, the Carothers and Reis theoretical expectation that all men are short-term maters and all women are not—and so we should expect taxons to form on questions about short-term mating psychology—is wrong-headed at its core. See also my previous posts on this here and here.

Auch hier zeigt sich der oben genannte Fehler. Es wird nach essentialistischen Unterschieden gesucht und dabei nicht hinreichend die Gewichtung beachtet. Beide Geschlechter verfolgen Kurzzeit und Langzeitstrategien, aber eben mit sehr unterschiedlichen Ansätzen.

Sadly, it gets worse. Carothers and Reis strangely included in their evaluation of this particular taxon many other items—such as reliably having orgasms and frequency of masturbation—that represent very different types sexual psychology. Including these questions alongside questions about short-term sexuality is a very odd decision from an evolutionary theory perspective. Seriously, why include these questions?

Die Antwort dürfte sein, dass man die Unterschiede kleiner haben wollte.

Most theories within the paradigm of evolutionary psychology expect psychological adaptations to be largely modular, turning on and off depending on factors such as sex, developmental experience, and local ecological condition (among other reasons). Combining radically diverse kinds of sexuality questions is an exceptionally poor empirical test of whether evolved sexual psychologies are taxonic by sex. Thus, the combinations of questions used by Carothers and Reis to evaluate the taxonic nature of sex differences in sexuality were problematic conceptually and empirically. Not so great. Not so science.

Es wird also letztendlich in der Studie von direkten essentialistischen Unterschieden, nicht von Häufungen ausgegangen. Was eben die Ergebnisse erheblich verfälscht.