March 26, 2008

Is autism the symptom of an "extreme white brain"?

In several previous posts, I've discussed Simon Baron-Cohen's theory of autism as a symptom of an "extreme male brain" (e.g. "Stereotypes and facts", 9/24/2006), and also Mary Bucholtz's hypothesis that nerdity is defined by "hyperwhite" behavior (e.g. "Language and identity", 7/29/2007).  I'm ashamed to say that it never seriously occurred to me to cross-pollinate these two theories, until (for serendipitous reasons) I recently read YW Wang et al. "The Scale of Ethnocultural Empathy: Development, validation, and reliability", Journal of Counseling Psychology, 50(2): 221-234, 2003.

Like Baron-Cohen and others over the years, Wang et al. find that females test higher on various scales of measured empathy -- in this case, on scales defined by patterns of answers on a newly-devised test instrument:

Effect size (d)
Empathic Feeling and Expression 3.89 0.87 4.47 0.78
Empathic Awareness 4.30 1.04 4.72 0.92

This is consistent with Baron-Cohen's theory that "empathizing" vs. "systematizing" is influenced by fetal testosterone levels (more on this in future posts). But fetal testosterone levels seem unlikely to be responsible for another result reported by Wang et al.:

Effect size (d)
Empathic Feeling and Expression 4.12 0.86 4.73 0.68
Empathic Awareness 4.43 0.99 5.05 0.82

Thus, in their sample at least, the difference between males and females in two empathy-related measures was smaller than the difference between whites and non-whites.

We don't know how general or stable this result is, because the sample was neither representative nor balanced:

After accounting for missing and invalid data (n = 16), we used a data set that included 323 undergraduate students who were enrolled in three Midwestern universities or colleges for the analysis. The sample included more women (66%, n = 213) than men (25%, n = 81), with 29 respondents not indicating their gender. Most of the participants were between the ages of 18 and 22 (97%, M = 19.73 years); most were single and had never been married (97%). [...] A majority of students in the sample described themselves as Caucasian (83%). African Americans constituted 6% of the sample, 5% were Asian American or Pacific Islander, 3% were biracial, 2% were Hispanic or Latino/Latina, and 1% were Native American.

On the other hand, the samples used in sex-differences research are often quite small, and are not in general demographically balanced. We wouldn't trust pollsters who claimed to characterize gender differences in the American electorate based on a sample of, say, 20 UCLA medical students. (Though if they use fMRI scans rather than questionnaires, they can apparently get past the editors at the New York Times.)

Let me note in passing that the magnitude of measured group differences in features like "empathy" may depend on whether the testing situation draws subjects' attention to their self-presentation. Rather than measuring how empathetic people are, some techniques seem to measure how empathetic they want others to think think they are. Thus according to the literature review in Nancy Eisenberg and Randy Lennon, "Sex Differences in Empathy and Related Capacities", Psychological Bulletin 94(1): 100-131, 1983:

In general, sex differences in empathy were a function of the methods used to assess empathy. There was a large sex difference favoring women when the measure of empathy was self-report scales; moderate differences (favoring females) were found for reflexive crying and self-report measures in laboratory situations; and no sex differences were evident when the measure of empathy was either physiological or unobtrusive observations of nonverbal reactions to another's emotional state.

A more recent survey (Richard A. Fabes and Nancy Eisenberg, "Meta-Analyses of Age and Sex Differences in Children's and Adlescents' Prosocial Behavior", 1998) came to a similar conclusion:

Sex differences were greatest when demand characteristics were high (i.e., it was clear what was being assessed) and individuals had conscious control over their responses (i.e., self-report indices were used); gender differences were virtually nonexistent when demand characteristics were subtle and study participants were unlikely to exercise much conscious control over their responding (i.e., physiological indices). Thus, when gender-related stereotypes are activated and people can easily control their responses, they may try to project a socially desirable image to others or to themselves.

To avoid misunderstanding, let me be explicit: Despite the humorous question in the title, I'm not suggesting that there are innate racial differences in empathy, nor that autism is caused by excessively caucasian genetics. Rather, I'm suggesting we should be cautious about attributing stereotypical male-female differences too quickly to the (developmental or immediate) effects of sex hormones.

[For a serious exploration of the effects of sex, race and class on rates of autism (or at least autism diagnosis), see Tanya Karapurkar Bhasin and Diana Schendel, "Sociodemographic Risk Factors for Autism in a US Metropolitan Area", Journal of Autism and Developmental Disorders, 37(4): 667-677 2007.]

Posted by Mark Liberman at March 26, 2008 06:51 AM