Delusions of Gender (41 page)

39
(Baron-Cohen, 2007), p. 160.

1
Quoted in (Verghis, 2009), p. 26.

2
(Hoff Sommers, 2008), para. 31.

3
See (Houck, 2009).

4
(Schaffer, 2008), entry 6 (‘The next best-seller’), para. 6.

5
For example (Hines, 2006a; Tavris, 1992, p. 54).

6
Gender identity in females with CAH seems to differ, albeit modestly, from control females. See for example (Berenbaum & Bailey, 2003), who found that gender identity scores of forty-three girls with CAH were intermediate between those of tomboys and sister controls, although this was not related to degree of genital virilisation or age of genital reconstructive surgery. A retrospective study of women with CAH found that women with the severest form of CAH had significantly greater cross-gender desire compared with controls (Meyer-Bahlburg et al., 2006). Also see (Hines, 2006b), figure 1, p. S117. Note that by gender identity I mean here responses to questions like, ‘Do you ever wish you could be a boy?’ rather than
confusion
over gender identity.

7
(Knickmeyer, Baron-Cohen, Fane et al., 2006; Mathews et al., 2009).

8
(Knickmeyer, Baron-Cohen, Fane et al., 2006).

9
See (Hines, 2004), p. 168.

10
(Puts et al., 2008).

11
(Pasterski et al., 2005).

12
For example (Berenbaum & Hines, 1992; Nordenström et al., 2002; Pasterski et al., 2005; Servin et al., 2003).

13
(Berenbaum, 1999). Also, (Servin et al., 2003) found stronger preference for masculine than feminine careers in seven- to ten-year-old girls with CAH, compared with controls.

14
It’s been suggested, for example, that prenatal androgen levels function as ‘the seeds of career choices’ (Berenbaum & Resnick, 2007).

15
As Bleier pointed out in her critique of earlier studies in this area, ‘authors and subsequent scientists accept at face value the idea of tomboyism [such as play preferences, clothing preferences, career interests, and so on] as an index of a characteristic called
masculinity
, presumed to be as objective and innate a human feature as height and eye colour. Yet ‘masculinity’ is a gender characteristic and, as such, culturally, not biologically, constructed’ (Bleier, 1986), p. 150.

16
(Golombok & Rust, 1993).

17
As found by (Hines et al., 2003).

18
(Jürgensen et al., 2007). The clinical population in this study had a 46,XY karyotype with a condition causing either partial or complete androgen insensitivity.

19
(Meyer-Bahlburg et al., 2006).

20
A Lego aeroplane had to be substituted for the Lincoln Logs in the UK sample because it didn’t show the expected sex difference in the US sample (Pasterski et al., 2005). Along similar lines, an earlier study found that control girls played
with Lincoln Logs more than
any other toy
, masculine or feminine (Servin et al., 2003). While it’s hardly the most scientific of sources, data from the Fat Brain Toys Web site suggest that parents and others underestimate how much girls will enjoy Lincoln Logs. The vast majority of these products (roughly 80 percent when I looked) are bought for boys.

21
(Berenbaum, 1999; Jürgensen et al., 2007; Meyer-Bahlburg et al., 2004).

22
(Auyeung, Baron-Cohen, Ashwin, Knickmeyer, Taylor, Hackett et al., 2009; Hines et al., 2002). (Udry, 2000) found a relationship between maternal levels of SHBG (which, as it binds to testosterone, can be understood as an inverse measure of free testosterone – see note 3 in
chapter 10
) and adult gendered behaviour. As noted in the earlier footnote, it is unclear whether mT or SHBG or neither is the appropriate index of exposure of the foetus to androgens. It’s also hard to determine from the information provided in this study to what extent the gendered behaviours measured indexed cultural ascriptions versus behaviours that are more plausibly regarded as psychological predispositions. (Knickmeyer, Wheelwright et al., 2005) found no relationship between aT and gender-typed play.

23
(Berenbaum, 1999), p. 108.

24
(Burton, 1977).

25
(Hines, 2004), pp. 127 and 128.

26
(Alexander & Hines, 2002). This study design, by the way, introduces other factors that might influence why a monkey might spend longer with a ball on Monday than a doll on Tuesday. For example, something that, to a monkey, is incredibly interesting might be taking place in the enclosure on Monday, while on Tuesday he may simply be in a less playful mood.

27
Frances Burton, personal communication, July 21, 2009. The study authors suggest that the appeal of the pan to the female monkeys may have been due to its red colour.

28
As noted by Ian Gold, Frances Burton and Lesley Rogers in their personal communication with me.

29
(Hassett, Siebert, & Wallen, 2008), p. 361. Although the researchers recorded the type of interaction with the toys, these data are not presented. The results are slightly different depending on whether total frequency or total duration of interaction is used. In the former case, the contrast between male and female plush toy play is also significant.

30
See (Hines & Alexander, 2008).

31
(Hines & Alexander, 2008), p. 478.

32
(Hassett et al., 2008), p. 363.

33
(Sax, 2006), p. 28.

34
(Mathews et al., 2009), replicating an earlier study discussed by Anne Fausto-Sterling. She points out that the idea that high foetal testosterone reduces
interest in infants implies ‘that testosterone interferes with the development of interest in infants, but that some general character called nurturance, which could get directed everywhere but to children, existed independently of high androgen levels.’ (Fausto-Sterling, 2000), pp. 289 and 290.

35
(Herman, Measday, & Wallen, 2003), p. 582. It should be noted that the findings with this androgen receptor blocker are sometimes paradoxical, suggesting that it may not have a straightforward androgen-blocking effect. However, early in gestation it does have the expected feminising effect on genitalia.

36
(Burton, 1977).

37
(Itani, 1959), p. 61.

38
(Burton, 1992), p. 45.

39
(Burton, 1977), pp. 11 and 14.

40
(Mason, 2002), p. 124.

41
(Herman, Measday, & Wallen, 2003). This study found that at one year of age, females differed from males only in touch behaviour, that is, the animal briefly touches the infant with its hand, although overall infant interaction approached significance.

42
See (Itani, 1959).

43
(Burton, 1977), p. 11.

44
(Burton, 1972).

45
(Hines & Alexander, 2008), p. 479.

46
(Hines, 2004), p. 181.

47
(Hines, 2004), p. 178.

48
Quoted in (Edge, 2005b).

49
(Pinker, 2005), para. 7.

50
(Baron-Cohen, 2005).

51
(Kimura, 2005), para. 2.

52
(Pinker, 2005), para. 12.

1
(Dana, 1915), para. 8.

2
(Russett, 1989), p. 191.

3
This section summarised from (Russett, 1989); quotation from p. 32. See also (Shields, 1975; Tavris, 1992).

4
(Hines, 2004), p. 6.

5
(Pease & Pease, 2008), p. 51.

6
Geoffrey Aguirre, quoted in (Lehrer, 2008), para. 17.

7
See (Weisberg, 2008) for an excellent overview.

8
See (Wallentin, 2009), also (Dietrich et al., 2001).

9
(Harrington & Farias, 2008; Ihnen et al., 2009; Kaiser et al., 2009). See also (Kriegeskorte et al., 2009; Vul et al., 2009) for arguments that reported correlations between brain activations and stimuli or social characteristics are sometimes biased or spurious due to invalid methods of analysis. Concern has also been expressed that the technology is being used in inappropriate ways. Neuroimaging expert Logothetis has recently complained that ‘[m]any of these [fMRI] papers are such oversimplifications of what’s happening in the brain as to be worthless’ and that ‘[t]oo many of these experiments are being done by people who, unfortunately, don’t really understand what the technology can and cannot do.’ (Quoted in [Lehrer, 2008], paras. 11 and 8, respectively.)

10
As Bleier points out, there was no a priori reason to suggest that greater lateralisation would be associated with superior visuospatial abilities. She also provides a good critique of the original corpus callosum data and interpretation (Bleier, 1986).

11
(Bleier, 1986), p. 154. Bleier provides an excellent and concise summary of the issues with the greater male lateralisation hypothesis and the inadequacy of the data for it. See also (Kaplan & Rogers, 1994).

12
(Sommer et al., 2004; Sommer et al., 2008), p. 1850 of 2004 paper. For the role of publication bias in the investigation of sex differences in language lateralisation, see also (Kaiser et al., 2009).

13
When Sommer and colleagues looked separately at the different types of dichotic listening tasks used, they found that one type of task, called the CV(C) task, did yield the expected sex difference. Interestingly, the CV(C) was used exclusively by researchers interested in sex difference issues. (In fact, generally, studies that were specifically interested in sex differences tended to find them, whereas studies that merely mentioned sex in passing tended not to.) Suspecting publication bias, they looked for evidence of sex differences in lateralisation in the CV(C) in a huge data set called the Bergen Dichotic Listening Database. This is an unpublished data set that is three times larger than all the CV(C) studies from the meta-analysis combined. There were no sex differences.

14
(Mathews et al., 2004).

15
See (Wallentin, 2009).

16
The aphasia rate following right-hemisphere damage was 2 percent for men and 1 percent for women (D. Kimura, ‘Sex differences in cerebral organisation for speech and praxic functions’,
Canadian Journal of Psychology
37 [1983], pp. 19–35), cited in (Sommer et al., 2004), p. 1849.

17
See (Hyde, 2005). Summarising the findings relating to language and communication from Hyde’s meta-analysis, Cameron writes, ‘[i]n almost every case, the overall difference made by gender is either small or close to zero.
Two items, spelling accuracy and frequency of smiling, show a larger effect – but it is still only moderate, not large.’ (Cameron, 2007), p. 43. Wallentin also concludes his review as follows: ‘A small but consistent female advantage is found in early language development. But this seems to disappear during childhood. In adults, sex differences in verbal abilities, and in brain structure and function related to language processing are not readily identified.’ (Wallentin, 2009), p. 181. Wallentin later draws attention to the file-drawer problem for research into sex difference in language skills.

18
See Bleier’s discussion of the initial report in 1982 by De Lacoste-Utamsing and Holloway (C. De Lacoste-Utamsing & R. L. Holloway, ‘Sexual dimorphism in the human corpus callosum’,
Science
, 216 [1982]: 1413–1432) which was based on fourteen brains, of unknown age or cause of death, and obtained a result that did not reach statistical significance. Bleier also made the important points that it is not known whether the size of the corpus callosum is related to the number of fibres
or
whether the number of fibres is related to degree of lateralisation of hemispheric function
or
whether lateralisation of hemispheric function is related to visuospatial ability (Bleier, 1986).

19
(Fausto-Sterling, 2000), and (Bishop & Wahlsten, 1997), p. 581.

20
(Wallentin, 2009), p. 178.

21
For example, one study found similar lateralisation (right) activity in the superior parietal lobe in both men and women – with males outperforming females (Halari et al., 2006). Another found no sex difference in behaviour, and found that males showed more bilateral activation in the parietal lobe while females showed more right lateralisation in this region (Clements et al., 2006). Gur and colleagues, on the other hand, found increased right lateralisation in men, who outperformed women, in the inferior parietal region (Gur et al., 2000). Another study found no differences in performance and no differences in lateralisation (Dietrich et al., 2001). This study also found much greater brain activations in women during their high-oestrogen phase which hints at an interesting problem for gender difference research in this area. Other researchers matched male and female performance and found sex differences in activations (which didn’t clearly suggest greater lateralisation in either group) that they suggested were due to different strategies in women and men (Jordan et al., 2002). Another study found no gender difference in either performance on brain activations, but significant brain activation differences between good and poor performers on the task (Unterrainer et al., 2000).

22
(Halpern et al., 2007), pp. 29 and 30.

23
(Baron-Cohen et al., 2005), p. 820, references removed.

24
Quoted in (Healy, 2006a), para. 14.

25
Quoted in (Healy, 2006b), para .22.

26
(Gurian & Stevens, 2004), p. 23.

27
(Pease & Pease, 2008), p. 110.

28
(Gray, 2008), see p. 39.

29
A point made by (Bleier, 1986).

1
(Romanes, 1887/1987), p. 11, footnote removed.

2
(Fausto-Sterling, 1985), p. 260.

3
(De Vries, 2004), p. 1064.

4
An example of this, in the rat, is described by (Moore, 1995), p. 53.

5
(Moore, 1995), pp. 53 and 54. Similarly, Haier and colleagues have suggested that ‘different brain designs may manifest equivalent intellectual performance.’ (Haier et al., 2005), p. 320.

6
See (Im et al., 2008).

7
(Leonard et al., 2008), p. 2929.

8
(Im et al., 2008; Leonard et al., 2008). Leonard et al. quoted on p. 2929. Effects of sex were very small, or nonexistent, once effect of total brain volume was taken into account. Leonard et al.’s findings with regard to grey matter in proportion to total brain volume are consistent, too, with work by Luders and colleagues, who also conclude that ‘brain size is the main variable determining the proportion of grey matter.’ (Luders, Steinmetz, & Jancke, 2002), p. 2371. Im and colleagues also argue that their results show ‘that sex effects are mostly explained by brain size effects in the cortical structure of human brains.’ (Im et al., 2008), p. 2188.

9
(Giedd et al., 2006), p. 159.

10
(Fine, 1990), p. 133.

11
(Baron-Cohen, Knickmeyer, & Belmonte, 2005), p. 821.

12
(Gur & Gur, 2007), p. 196.

13
Ian Gold, personal communication, October 24, 2008.

14
I am very grateful to Ian Gold, whose insights have greatly enhanced my understanding of the problems inherent in trying to relate brain structure to brain function.

15
(Halari et al., 2006), see pp. 1 and 3.

16
(Gur et al., 1999).

17
Quoted in (University of Pennsylvania Medical Center, 1999), para. 7.

18
(Gur et al., 1999), p. 4071. Regarding the point that correlation doesn’t mean
causation, some third factor (or complex of factors), like education, could enhance both white matter volume
and
spatial ability.

19
(Gur & Gur, 2007), p. 196.

20
(Gur et al., 2000), p. 166.

21
(O’Boyle, 2005; O’Boyle et al., 2005; Singh & O’Boyle, 2004).

22
Again, this is an issue raised long ago by Ruth Bleier who pointed out the circularity of the reasoning that men are superior in visuospatial skills because they have right-hemisphere lateralisation for visuospatial processing, and that right-hemisphere lateralisation is superior for visuospatial processing because men are superior at visuospatial processing and they show right-hemisphere lateralisation (Bleier, 1986).

23
See (Russett, 1989; Shields, 1975).

24
H. Ellis,
Man and Woman: A Study of Human Secondary Sexual Characteristics
(London: Walter Scott, 1894), p. 28. Quoted in (Russett, 1989), pp. 184 and 185.

25
(Pease & Pease, 2008), pp. 145 and 146, respectively. Illustrations appear on p. 145.

26
(Pease & Pease, 2008), p. 145.

27
The first study is C. M. McCormick, S. F. Witelson, and E. Kingstone, ‘Left-handedness in homosexual men and women: Neuroendocrine implications’,
Psychoneuroendocrinology
15, no. 1 (1990), pp. 69–76. The second study is S. F. Witelson, ‘The brain connection: The corpus callosum is larger in left-handers’,
Science
229, no. 4714 (1985), pp. 665–668.

28
(Hall et al., 2004). Although the Peases also describe the Witelson emotion study in the 1999 edition of their book, researchers often present their results before publication, which can take many years. I contacted Pease International in the hope that the Peases might be able to clarify to what research they are referring in this passage, but they were unable to assist.

29
(Pinker, 2008), p. 116.

30
In discussing these results, I focus on between-group comparisons between males and females, rather than within-group contrasts, on the basis of the argument made by Kaiser and colleagues that ‘[o]nly by comparing women and men directly with one another within one statistical test can significance be ensured.’ (Kaiser et al., 2009), p. 54.

31
(Hall et al., 2004), p. 223.

32
(Hall et al., 2004), p. 223.

33
(Bennett et al., 2009), p. S125.

34
See (Ihnen et al., 2009).

35
For discussions of the role of reverse inferences in understanding cognitive mechanisms, limitations and conditions in which they are more or less likely to be a valid form of inference, see (Poldrack, 2006; Poldrack & Wagner, 2004).

36
For example (Blakemore et al., 2007; Burnett et al., 2009; Haier et al., 1992).

37
(Bird et al., 2004), p. 925.

38
(Buracas, Fine, & Boynton, 2005).

39
(Friston & Price, 2001), p. 275.

40
(Lehrer, 2008), para. 7.

41
(Kaiser et al., 2009).

42
(Miller, 2008), p. 1413.

43
Men’s brains are, on average, about 8 to 10 percent larger than female brains. Beyond this, as Kaiser et al. have pointed out, results demonstrating sex differences in ‘
a/symmetries
between the left and right hemisphere in anatomy and function, the size of the
corpus callosum
, and the
extent
of defined brain areas … have never been both conclusive and unchallenged’ (Kaiser et al., 2009), p. 50, emphases in original, references removed. Also, as discussed in this chapter, what appear to be sex differences in brain structure may turn out to be differences between people with larger versus smaller brains. Nor does the existence of differences in the brain indicate their origins. One last point is the importance of not assuming that sex differences observed in the rat apply to humans. With these extremely important caveats in mind, a brief overview of research finding sex differences in brain anatomy, neurochemistry and function, and discussion of their potential importance in understanding clinical disorders, is provided in (Cahill, 2006).

44
(Weisberg, 2008), p. 56.