Too Many, Too Soon?

EXECUTIVE SUMMARY: One of the misgivings about current early-childhood vaccination recommendations is that they involve exposing infants to so many infectious agents. While there's already been research into the effect of multiple vaccines on the immune system, Smith and Woods (2010) are the first to look at whether getting lots of vaccinations very early in life might have any effect on the nervous system.

Using the vaccination records and neuropsychological data on a group of children born between 1993 and 1997 that were gathered and made publicly available for an earlier vaccine-safety study, they did two different group comparisons between children who had received all the recommended vaccines on time and children who hadn't. They found no ill effects of exposure to lots of different vaccines within the first seven months of life; the only effects of earlier vaccination on neuropsychological development that they found were beneficial ones, but these mostly did not survive controlling for other demographic variables.
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In an interview with The Thinking Person's Guide to Autism editor Shannon Des Roches Rosa, Autism's False Prophets and Deadly Choices author Dr. Paul Offitt mentioned a study published last May in Pediatrics that addresses the "too many, too soon" version of the vaccines-cause-autism hypothesis.

Some parents of very young children, while they might not believe that any single vaccine is dangerous, notice that a lot more vaccines are recommended within the first six years of life now than there used to be, and wonder whether it might damage a child's immune system to expose that child to so many antigens within such a short period of time*.

While there was already evidence that the current vaccine schedule is safe from an immunological standpoint, Smith and Woods (2010) are the first researchers to look at its potential impact on the developing nervous system.

Their study re-analyzes data gathered for an earlier study looking at neuropsychological outcomes in 7-to-10-year-old children exposed to thimerosal in vaccines; those researchers recruited children from four HMOs participating in the CDC's Vaccine Safety Datalink project, tested them on 42 measures of neuropsychological outcomes (which broadly fell into seven domains --- speech and language, verbal memory, fine motor coordination, attention/executive functioning, behavioral regulation, tics, and general intelligence --- and also included two other tests, one of visuospatial ability and another of letter and word identification; see Table C, or pages 9-11 of this document, for a complete listing), and looked for relationships between a child's performance on those tests and the amount of thimerosal that child had been exposed to, as estimated from vaccination records.

That study didn't find much of an effect for early thimerosal exposure --- it found a small scattering of statistically significant effects, but those effects were 1) often not the same in boys and girls, or in children belonging to different HMO groups, 2) evenly divided between higher mercury exposure --> better outcome and higher mercury exposure --> worse outcome, and 3) very small. That suggests to me that many of those associations might simply have been noise.

What's more important in terms of whether the "too many, too soon" hypothesis holds water is the raw data those researchers collected --- complete vaccination records and neuropsychological test results for 1,047 children. The existence of those data allowed Drs. Michael J. Smith and Charles R. Woods to look for relationships between timing of vaccination in early infancy and later neuropsychological outcomes.

They compared outcome data for the 491 children who got all the recommended vaccines on time (which they defined as within 30 days of the recommended age, given in months, on the CDC's vaccination schedules for 1993-1997) with the data for the rest of the children (who fell into two categories: those who had gotten all of the recommended vaccines, but just didn't get them at the recommended time, and those who hadn't gotten all the shots by the time they participated in Thompson et al.'s study), finding that children who got all their recommended shots on time performed better than the other children on 12 of the 42 outcome measures --- the Boston Naming Test, the grooved pegboard (a test of fine-motor coordination), the metacognition subscale of the Behavior Rating Inventory of Executive Function, teacher ratings for inattention and hyperactivity, parent rating for stuttering, and verbal, performance and full-scale Wechsler IQ. There was no measure on which they performed worse than the less-vaccinated group.

Because there were demographic differences between the families of children who were vaccinated on time vs. children who weren't, the researchers also did a multivariable analysis to try and control for those factors. That analysis found only two (small) between-group differences, but both of these were also in the fully-vaccinated kids' favor. (They scored 1 point higher on the speeded-naming subtest of the Developmental Neuropsychological Assessment's Language and Communication domain, and also tended to have slightly higher performance IQs).


They also did a secondary analysis, dividing the study participants into three groups, based on "timeliness" of vaccine receipt. The "most timely" group (n = 310) was created by dividing all the children who'd gotten all 10 of the vaccines recommended for the first year of life into quintiles based on how old they were when they completed the schedule. The first two quintiles, or the 40% of children who completed the schedule earliest (i.e., within the first seven months of life), constituted the most timely group, while the children who had gotten six or fewer of the ten recommended vaccines by the time they were seven months old made up the "least timely" group (n = 112).

(The rationale for doing this secondary analysis was to look for any effect of spacing all the vaccinations really close together --- the children in the "most timely" group had crammed the ten first-year vaccines into the smallest window of time. Similarly, the group they're being contrasted with represents the opposite extreme in terms of vaccine compliance --- these are the children who've gotten the fewest shots within that same seven-month window of time. If there is a spacing effect, it ought to show up in a comparison between those two groups, if it shows up anywhere.)

The results of the secondary analysis were a lot like those of the primary analysis: univariate analysis turned up fifteen outcome measures on which the most-vaccinated children outperformed the least-vaccinated ones (including most of the same measures identified as showing a difference between groups in the primary analysis), while multivariate analysis found no difference between the groups. Overall, this study failed to find evidence of any deleterious effects of multiple vaccinations on neuropsychological development, even when those vaccines are spaced very close together very early in life.

(One of the potential objections the authors deal with in their Discussion section involves the fact that the vaccination schedule has changed since the mid-1990s, but they figure that, since most of the children in their study received the version of the combined diphtheria, tetanus and pertussis vaccine that includes whole-cell pertussis, their overall antigenic load would be heavier, not lighter, than what children are exposed to today. See my note below for more explanation about changes in the pertussis vaccine.)


Sources:
Smith, M., & Woods, C. (2010). On-time Vaccine Receipt in the First Year Does Not Adversely Affect Neuropsychological Outcomes PEDIATRICS, 125 (6), 1134-1141 DOI: 10.1542/peds.2009-2489

Thompson WW, Price C, Goodson B, Shay DK, Benson P, Hinrichsen VL, Lewis E, Eriksen E, Ray P, Marcy SM, Dunn J, Jackson LA, Lieu TA, Black S, Stewart G, Weintraub ES, Davis RL, DeStefano F, & Vaccine Safety Datalink Team (2007). Early thimerosal exposure and neuropsychological outcomes at 7 to 10 years. The New England journal of medicine, 357 (13), 1281-92 PMID: 17898097

*Actually, while it looks like we're throwing more things at young children's immune systems now than before, when you just look at the number of vaccines children receive now versus thirty years ago, the composition of vaccines has changed, too, so that each vaccine now contains fewer antigens than they used to. Looking at this table in a 2002 review on vaccine safety by Paul Offitt and colleagues, the switch from using the whole bacterium that causes whooping cough, Bordetella pertussis, to just using the toxin it secretes cut the number of distinct antigens in the pertussis vaccine from around 3,000 to just two to five (depending on how many other bacterial cell components are still mixed with the active ingredient, the toxin). That whole-cell pertussis vaccine looks like the proverbial pig in the python, swelling the total number of antigens in all the recommended vaccines to 3,000+ during the time period in which it was used. Now, with the adoption of the acellular pertussis vaccine, the total number of antigens in all the early-childhood vaccines is about 125, give or take a few. So the question of antigen overload is actually a lot more complicated than just comparing the number of vaccines recommended at different points in time, and, if anything, a closer look seems to tell us that young children's developing immune systems are less overloaded by the current vaccine schedule, not more.

In Which I Finally Get Back to Writing About Autism in Fiction

Marti Leimbach's 2006 novel, Daniel Isn't Talking, covers a lot of the same narrative territory as the first volume of Keiko Tobe's manga series "With the Light" --- the protagonist is a young wife and mother who discovers that her son is autistic, and the story follows this pattern, more or less: 1) following her child's diagnosis, the main character goes into shock, grieves for the "normal" child she wishes she had instead, and watches her life and her marriage fall apart around her; 2) she comes out of her depression and begins to fight for her child, wrangling with various therapists, educators and bureaucrats over what sort of treatment to pursue; and 3) as she, and her allies in the school and health-care systems, and among her in-laws, begin to find schools, therapies, and accommodations that work well for her child, her life regains a semblance of order and she comes to understand her child better and love him for the person he is more than she grieves for the person he's not.

I'll review this book as a whole later, but what I want to focus on right now is Leimbach's use of military metaphors throughout this book: her protagonist, Melanie Marsh, refers to herself repeatedly as someone fighting a war against autism.

Here are some instances of this parenting-as-combat, autism-as-The-Enemy metaphor:

Stephen's uncle Raymond, that dear man, rings to tell me not to regret giving Daniel the MMR. His voice is loud in the receiver; he speaks as one who has endured early attempts at telephonic communication, who has shouted into tortoiseshell receivers fixed on wall phones, gone through operators in order to place calls. Now he tells me that in his time he has seen children die of measles; they died in droves when he was a boy. Temperatures of a hundred and six, their brains burned inside their skulls. I mustn't regret a thing.

"Please come and see us," I say to him. Raymond lives on the other side of London. He owns the same house in which he grew up and that he shared with his mother until her death some thirty years ago. He has taken me around the upstairs to show me the scars in the ceiling where a bomb came through the roof during the war. He has stood by me by the window and pointed to the areas, now dense with houses, where once there was nothing but craters and buildings in ruin. He has seen things he will not tell me about, the experiences of being a soldier. "I would not wish my memories upon you," he once said, then asked me if I could find a use for the cake pan his mother used to bake birthday cakes for him and his brother when they were children. Whether, too, I might like some of his mother's damask linen.

"I will come," he says now. "But meanwhile, you mustn't blame yourself."

"I don't," I tell him, a lie. I am fast becoming a good liar, which I discover is a means of camouflage for the protection of others, those who have not been conscripted into this battle with autism, those who have normal children, for example.

(Notice, too, the juxtaposition of Melanie's silence, as an embattled (in a metaphorical sense) Mom of an Autistic Kid with the silence of this other character, Raymond, who has fought in an actual war. He and Melanie have identical reasons for concealing their darkest thoughts from each other, and I think Leimbach's highlighting the similarities between Melanie and Raymond, and their reasoning behind fencing off a portion of their minds from other people, for those other people's protection, helps emphasize the mom-as-soldier metaphor in a way that merely explicitly stating it, as Melanie does when she says she has been "conscripted into this battle with autism," can't do.)

Another example:

"What about all these other therapies?" I ask Andy. There's art therapy, music therapy, sound therapy, therapies that involve brushing the child in order to help with "sensory" issues, not to mention many highly structured teaching practices that happen in schools.

Andy is setting out a new track [of a toy train set; he's playing a game with Daniel, who likes Thomas the Tank Engine], one that finishes at the edge of a seat cushion so the train will crash to the floor. He looks at me, then back down to the track again. He says, "You can try other things. Mostly they won't hurt him."

"But will they help him?"

He shrugs. "I'm a play therapist. And I like the behavioral approach." A flat statement, a non-comment. But it feels to me he is saying much more, that I am speaking to someone in the trenches, who has been in the trenches for a long time, who is battle-weary but full of wisdom. It is as though he is saying, "Here is the only gun that fires. Pick up the bloody gun."

Here's another metaphor that I think is related to the parenting-an-autistic-child-as-war metaphor; Melanie compares her efforts to get her son, Daniel, to speak before it's "too late" for his prognosis to improve to trying to get him out of a burning building:

To ask a person to do nothing for their child or to do very little is unfair. For them to do nothing means they have to fight the overwhelming urge to push away the danger, to run through the flames, to slay the dragon. However hopeless the situation might appear, it is infinitely more difficult to do nothing than even an ill-considered something. I knew a man whose teenage son was stabbed to death in the early hours of a Saturday night by kids his own age who wanted the sneakers he was wearing. His father had repeated dreams --- the day-and-night dreams that I came to be familiar with after Daniel's diagnosis --- in which he was there when it happened, just behind the gang as they circled his boy. There, hidden in the luxuriant green of unkempt bushes, he would be crouching. Or he stepped off the bus just in time to reach over and pluck his son, vibrant and alive, from the hands of his attackers. In his dreams, the five-inch steel blade that pierced his son's chest never so much as scratched his skin. Instead, he took his child in his arms as he had as a baby, running at a supernatural speed, flying even, not knowing where he was going but knowing it was away --- away from threat and danger and harm, away from four youths and their deadly, sharpened blade.

But the dreams were only dreams. The reality was, the boy died. The father slept.

My reality is that my child lives peacefully within a dysfunctional brain while I search madly --- tear myself apart --- trying to think for the both of us how to get out of the burning building of autism. Even using this method --- this play therapy mixed with applied behavior therapy and whatever else Andy brings to bear --- there are limitations. With every learned word or spontaneous moment of play, I see Daniel becoming more like any other child, less "autistic"-seeming, and I know that if he will interact with others as he is now interacting with Andy, with me, with [his sister] Emily, his life will not be entirely ruined by the condition. But there is also a time factor. As he develops so do all the other children around him. He has to race to catch up or never catch up at all. I understand this very well. It is almost as though someone has told me, "If he is going to escape the fire, he must do so early, before the roof caves in."

There's another comparison to armed conflict at the beginning of this quoted passage, where Melanie compares her own angst over having an autistic son to the recurring nightmares of a father of a murdered son; placing herself in the father's shoes, Melanie makes Daniel's autism into the gang of teenage thugs that took the other boy's life.

Later in the same passage, Daniel's autism becomes a burning building that he must escape --- that Melanie has to lead him out of.

All of these metaphors work to convey several things that I think Marti Leimbach was trying to emphasize with them --- Melanie's desperation, her constant feeling that something of life-or-death importance is happening in her son's life, that will determine the course of her son's life, that she cannot figure out how to wade in and help him. Her repeated use of images of battle, of sacrifice, of terrible, outsized, Herculean struggles waged on his behalf, seem like they reflect the gap between what she can do for him --- what she is doing for him --- and what she wishes she could do for him. She reaches for life-and-death scenarios to compare her efforts to, and most often she returns to the battlefield for her metaphor of choice.

While I am sure Leimbach chose these metaphors to highlight her character's sense of living under extreme circumstances, and her frustrated desire to help her son, I also see something in these metaphors that I'm not sure she meant to imply.

What all of these metaphors --- of war, of individual combat, of fleeing a collapsing, burning building --- do is they separate Daniel from a part of himself, and set that part in conflict with the whole person. To save her son, Melanie makes war on ... her son. She doesn't see it that way; she sees her war as being against the thing that has taken her son from her, but Daniel hasn't been taken from her at all. He's still there, he's just not the way she wishes he could be.

This conflict Melanie sees between Daniel and Daniel's autism reminds me of the autism-as-prison metaphor I described in my post about spatial metaphors and autism:

One thing the autism-as-container metaphor tends to leave muddled is where the autistic person dwells in this metaphorical space. It's quite eloquent on the position of the parents, peers and teachers trying to relate to this strange being --- we're given to understand quite clearly that they feel locked out and exhausted from battering at the door --- but what's not always clear is whether the autistic person is in the metaphorical Fortress of Solitude, or whether they are it.

Judy and Sean Barron's 1992 book There's a Boy In Here makes it unusually clear: Sean is inside his autism, his thoughts, feelings, desires, and self obscured from his mother's sight by his intense anger, his tantrums, his reckless, aggressive and often destructive behaviors. But in other books, like The Siege (which I haven't read) and Bruno Bettelheim's mother-blaming opus The Empty Fortress (which I likewise haven't read), it's not clear whether the walls that the authors advocate tearing down imprison the child, or whether they constitute a part of hir, like a protective cocoon or exoskeleton. The act of trying to "break through" to an autistic child becomes a violent one if the latter construction is implied ...

Melanie's understanding of her son's autism in Daniel Isn't Talking is, as I mentioned above, stuck in "But this is not my child!" mode. For her, Autism is a hostile Other that has taken, and changed, her son. Her son's autism might be a part of him, but it's a dangerous, diseased part that Melanie believes Daniel will be much better off without. Because she sees Autism as a separate, hostile entity and Daniel as its victim, she can cast herself as Autism's implacable foe without seeing any tension between that role and the unconditional love of Daniel that the maternal role demands.

Other reviews of this book: Sharon at The Voyage, Kristina Chew at Blisstree.com

Heart Necklace

(Also: Reddest Blog Post Ever!)

My brother gave me a gift card for Christmas, and this is one of the things I decided to spend it on: a pewter Human Heart Necklace from Anatomology.com, with a garnet lens hanging alongside the heart pendant.
The necklace is a bit longer than I would've liked --- they sell a shorter version, with a 17" chain rather than the 30" one I have here, but I didn't think the 17" one came with the red stone.

Here I am wearing it in tandem with a red leather rose choker I got at a Renaissance Festival:

(The heart necklace is pulled back a bit so it will sit higher in this picture, so that I could get a better shot of the rose).

Here's the pendant where it normally falls:

Now This Is Weird

(If you insist on having some context for this wonderfully bizarre image, it's here.)

So, Antarctic Press has started a new comic-book series featuring Sarah Palin and a suit of steam-powered robot armor.
Chris Murphy at Comics Alliance has reviewed the first (and so far only) issue, which he declares "so bad it's good":

Steampunk Palin hopes to capitalize on the popularity of two things. First, former Vice Presidential Candidate and ex-Governor of Alaska Sarah Palin, whose life story of beauty queen to elected official to media celebrity has captivated a nation, both for those who find her to be an inspiring voice to the Tea Party movement of libertarian-influenced conservatives, and those who derive perverse entertainment from many of her public statements and behavior.

The second thing is steampunk, a literary genre that borrows the notions of cyberpunk and transplants them into an alternate history past or fantasy world, usually influenced by the works of H.G. Wells or Jules Verne. It's often characterized by the use of advanced technology substitutes reliant on non-electrical power, and a visual aesthetic heavy on intricately designed gearworks. ...

And while I'm willing to believe this book when it tells me it's trying to depict Sarah Palin, my response to the idea that it can be characterized as steampunk is more along the lines of "Hold on there." Although to be fair to the book, Steampunk Palin defies classification into any literary genre, unless there's a genre I'm unaware of simply called "WTF?!?"

Some other high points of weirdness: first, Sarah Palin isn't the only contemporary political figure to get the steam-powered robot upgrade: Barack Obama is also turned into a cyborg ("Robama"), and John McCain gets a robot arm, and they all team up to save Alaska from marauding Russians and rapacious energy companies. Second, the nefarious plot to steal all the energy (all of it!) is headed by none other than Al Gore! An evil Al Gore, going by the nom de guerre "Professor Greenhouse."

I figured a publishing house that could produce that would probably have lots of other, equally oddball offerings, and Antarctic Press's website doesn't disappoint.

There's another, even more cheesecake series starring Palin: "Sarah Palin, Rogue Warrior" ...

... "President Evil," in which all the dead U.S. Presidents rise from their graves to feast on the living, and President Obama has to battle them ...
... and, probably the least off-the-wall of any of them, "The Governator," which imagines Arnold Schwarzenegger's tenure as Governor of California as it might have gone if he really were an amalgam of all his action-hero movie characters:
Unfortunately, these politicians are not all lampooned equally in their comic-book representations; Sarah Palin, besides being made into a cartoon character, is also objectified and sexualized in ways that Barack Obama, John McCain, and Arnold Schwarzenegger are not. (About a third of the pages in Steampunk Palin #1 are devoted to pinup art of her; you can see an example at the Comics Alliance post I linked).

That's not going to surprise anyone who's even slightly familiar with either comic books or how Sarah Palin is usually depicted in the media; it's still depressing, though, that we're not yet able to caricature female politicians without turning them into hags, bimbos or sex objects.

Zany Vintage Ads - The Gift That Keeps On Giving!

I have a reproduction of Giant-Size X-Men #1, from 1975 --- this one, to be exact --- that also includes reproductions of the ads that were included in that initial printing.

Most of them are nothing special --- not appreciably different from the ads that run in comic books today, offering mail-order products guaranteed to give you a muscular body, mastery of hypnotism or martial arts, get-rich-quick schemes or collectible comics and/or action figures.

But there was one that made me laugh, not least because of its incredible seventiesness:

Stick-on fake facial hair! So that you, too, can have a sexy Van Dyke beard and mutton-chop sideburns like this guy! (I have no idea what is up with the hair on top of his head, though; the way they've drawn it, it looks more like he's wearing a deflated basketball for a skullcap).

Anyway, here's the copy, in case it's not legible in my scan:

ENJOY AN EXCITING, ROMANTIC

LOOK

IMPRESSIVE ANYTIME!

QUICK CHANGE to suit your mood time:

Send for Mustache, Sideburns and Van Dyke at once! Simply check the color you want or send a sample of your hair and leave the matching to our expert. MAIL COUPON NOW!

Adheres securely ... off and on in seconds ... can be worn as is or trimmed to just the style you want.

They then provide a listing of hair-color options, and a mailing address for "Masculiner Co." somewhere in New Jersey.

Unfortunately, since the ad is actually from 1975, the company probably doesn't exist anymore, and even if it did the offer wouldn't still be valid. (It says that at the bottom of every ad page: "Facsimile advertisement, no longer valid.")

Heck, I might even get myself some stick-on '70s-style sideburns if I could find them for super cheap. They look fun.

(I have some teeny-tiny, baby sideburns of my own that I kind of wish were bigger and more noticeable. They are a shade or two darker than the rest of my hair.)

An Intriguing Idea from Cordelia Fine's "Delusions of Gender"

In Chapter 19 (titled "Gender Detectives") of her book, Delusions of Gender (which I review here), Cordelia Fine describes how children learn to sort themselves into gender categories:

Anyone who spends time around children will know how rare it is come across a baby or child whose sex is not labeled by clothing, hairstyle, or accessories. Anyone with ears can hear how adults constantly label gender with words: he, she, man, woman, boy, girl, and so on. And we do this even when we don't have to. Mothers reading picture books, for instance, choose to refer to storybook characters by gender labels (like woman) twice as often as they chose nongendered alternatives (like teacher or person). [Gelman, Taylor & Naguyen, 2004] Just as if adults were always referring to people as left-handers or right-handers (or Anglos and Latinos, or Jews and Catholics), this also helps to draw attention to gender as an important way of dividing the social world into categories.

This tagging of gender --- especially different conventions for male and female dress, hairstyle, and accessories, and use of makeup --- may well help children learn how to divvy up the people around them by sex. We've seen that babies as young as three to four months old can discriminate between males and females. At just ten months old, babies have developed the ability to make mental notes regarding what goes along with being male or female: they will look longer, in surprise, at a picture of a man with an object that was previously only paired with women, and vice versa. [Levy & Haaf, 1994] This means that children are well-placed, early on, to start learning the gender ropes. As they approach their second birthday, children are already learning to pick up the rudiments of gender stereotyping. There's some tentative evidence that they know for whom fire hats, dolls, makeup, and so on are intended before their second birthday. [Serbin, Poulin-Dubois, & Eichstedt, 2002 (PDF); Poulin-Dubois et al., 2002] And at around this time, children start to use gender labels themselves and are able to say to which sex they themselves belong. [Zosuls et al., 2009]

It's at this critical point in their toddler years that children lose their status as objective observers. It is hard to merely dispassionately note what is for boys and what is for girls once you realize that you are a boy (or a girl) yourself. Once children have personally relevant boxes in which to file what they learn (labeled "Me" versus "Not Me"), this adds an extra oomph to the drive to solve the mysteries of gender. [Martin, Ruble & Szkrybalo, 2002 (PDF); Martin & Halverson, 1981] Developmental psychologists Carol Martin and Diane Ruble suggest that children become "gender detectives," in search of clues as to the implications of belonging to the male or female tribe. [Martin & Ruble, 2004 (PDF)] Nor do they wait for formal instruction. The academic literature is scattered with anecdotal reports of preschoolers' amusingly flawed scientific accounts of gender difference:

[O]ne child believed that men drank tea and women drank coffee, because that was the way it was in his house. He was thus perplexed when a male visitor requested coffee. Another child, dangling his legs with his father in a very cold lake, announced "only boys like cold water, right Dad?" Such examples suggest that children are actively seeking and "chewing" on information about gender, rather than passively absorbing it from the environment. [Ruble, Lurye, & Zosuls, 2008]

In a later chapter, she hypothesizes that this drive to delineate gender categories, and to sort oneself into one of them, might stem from a broader human desire to belong to a group:

As we've seen, children are born into a world in which gender is continually emphasized through conventions of dress, appearance, language, color, segregation, and symbols. Everything around the child indicates that whether one is male or female is a matter of great importance. Meanwhile, at about two years of age, children discover on which side of the divide they are located. It remains to be seen, in my view, whether subtle gender differences in babies' toy preferences before they know their own sex can be explained by socialization by parents, unwitting or otherwise. But once children know their own sex, in theory they can start to take socialization into their own hands.

And it's plausible to think that they will. Gaining membership to a group, any group, normally brings a money-back guarantee of favoritism. In the infamous minimal group studies conducted by Henri Tajfel and colleagues, adults are randomly assigned to trivial groups. For example, they are asked to estimate the number of dots on an array, and then categorized as either a dot overestimator or a dot underestimator. It's hard to imagine a categorization of less psychological significance. And yet membership of even such arbitrarily assigned and short-lived social categories can engender a warm glow toward fellow dot overestimators (or underestimators) that does not extend so far as those who take a different approach to dot guesstimating.

Children, it turns out, are also susceptible to an in-group bias to prefer what belongs to their group. Recent work by Rebecca Bigler and colleagues has shown that this is especially the case when groups are made visually distinct, and authority figures use and label the groups. In one study, three- to five-year-old preschoolers in two child-care classrooms were randomly assigned to the Blue group or the Red group. Over a three-week period all the children wore a red or blue T-shirt every day (according to the group to which they'd been assigned). In one classroom, the teachers left it at that. The color groups were not mentioned again. But in the other classroom, the teachers made constant use of the two categories. Children's cubbies were decorated with blue and red labels, at the door they were told to line up with Blues on this side and Reds on that side, and they were regularly referred to by group label ("Good morning, Blues and Reds"). At the end of the three weeks, the experimenters canvassed each child's opinion on a number of matters. They found that being categorized as a Red or a Blue for just three weeks was enough to bias children's views. The children, for example, preferred toys they were told were liked by their own group and expressed a greater desire to play with other Red (or Blue) children. While some forms of favoritism were common to all the children, more was seen in kids from the classroom in which teachers had made a bigger deal out of the Red versus Blue dichotomy.

Just imagine how powerfully exactly the same psychological mechanisms can drive in-group pride and out-group prejudice when it comes to gender. In the young child's world, gender is the social category that stands out above all others, right from the start. Conventions of clothing and accessories mean that gender is extremely obvious visually, and boys and girls may be regularly labeled and organized ("Now it's the boys' turn to wash their hands") by gender, especially in early education settings. And, unlike adults and older children, younger children don't tend to have other social categories like jock, doctor, Christian or artist with which to identify. The drive for group belonging may explain why young children insist on girlish or boyish behavior or dress even in the face of parental displeasure, suggest Diane Ruble and colleagues.

This theory is really interesting to me, and I particularly like the idea that it's not a particular set of gender-related traits that are innate, but rather 1) the capacity to distinguish the sexes, and to know one's own sex, and 2) the drive to find one's place in the social group in which one lives. In our large, mobile, relatively fluid but still highly gendered society, gender roles are probably going to be the first social identities that suggest themselves to a child.

I like this theory, because it explains a lot of the same things that "hard-wiring" theories of gender explain, but it's much more flexible. Which is good, considering that gender norms have changed, a lot, throughout history and today's conceptions of the Eternal Feminine or the Eternal Masculine sometimes conflict with these past notions of masculine and feminine.

(One trivial example: pink and blue. Pink used to be for boys, because it was like a softer version of red, while blue, the color of the Virgin's veil, used to be for girls. Now, of course, it's the other way round).

There is one thing that the book doesn't address, that I'd like what Fine (or any of those developmental psychologists she cites) thinks about it: given that the usual course is for children to discover what sex they are, and then become interested in learning, and correctly performing, the gender role corresponding to that sex, why do some children choose a different sex to emulate?

I can remember that, while I did not always think of myself as having gender (or even as being human) throughout my entire childhood, when I did think in those terms I always knew two things: 1) I was a girl, and 2) I was, and wanted to be, like a boy. And when I grew up, I would be a woman who was like a man. Furthermore, this wasn't just who I was in the absence of any gender self-socialization; I self-socialized in very much the way Fine describes. I just chose to learn, and conform to, the masculine role.

That sort of thing --- why you would choose to imitate people of the other sex, rather than your own --- isn't answered. And neither is the related matter of how transgenderedsexual* people form their gender identities --- they often have strong senses of themselves as sexed, gendered beings, but the sex and gender categories they feel they belong to are not the ones assigned to them at birth.

*Edited 1/23/11 to reflect Juliet's preference, stated in comments, for "transsexual" over "transgendered."

Gender on the Brain: Cordelia Fine Exposes "Neurosexism"

I was given Cordelia Fine's new book, Delusions of Gender, as a Christmas present, and I just finished reading it a couple days ago*.

It's very easy and fun to read, despite going into a lot of technical detail about the design of various studies (although she manages to write about those details in wonderfully clear, simple prose --- I *try* to do that on this blog, but I think her book is better-written, and easier to understand, than many of my researchy posts) and trying to tease out the separate strands of a very complicated knot of biology, psychology, culture that lies underneath the surface of what we understand gender to be.

She spends a lot of time discussing a topic that's also been on my mind a lot recently: fetal testosterone. She takes a much broader view of this literature than I do, because I am focusing exclusively on those studies that I consider relevant to the "extreme male brain" theory of autism, while she's addressing the whole idea that a "male brain" and a "female brain" even exist, much less that they differ as radically as most people writing popular (and academic) books on brain sex seem to think.

She peppers her book with quotations from such works as Louann Brizendine's The Female Brain (if you have time, read Mark Liberman's series of posts on Language Log debunking this book; they're hilarious and eye-opening), Leonard Sax's Why Gender Matters, John Gray's however-many-there-are-now Mars and Venus books, Allan and Barbara Pease's** Why Men Don't Listen and Women Can't Read Maps, and various books authored or co-authored by Michael Gurian of the Gurian Institute: Leadership and the Sexes, It's a Baby Girl!, and What Could He Be Thinking?

As an additional bit of context, she also quotes liberally from sources a hundred years old or more, laying out their nearly-identical visions of the masculine and feminine mind; the only difference is in what kind of pseudoscientific technobabble is used to justify the idea of separate spheres for men and women: in the old books, it is woman's physical frailty, nervous sensitivity and smaller brain that fit her for a purely domestic life, while in the new books, it is her relatively larger corpus callosum, her greater verbal fluency and emotional sensitivity, that fit her for the caring professions or for full-time wife-and-motherhood.

The book is divided into three parts, the first and last of which (called "'Half-Changed World', Half-Changed Minds" and "Recycling Gender") deal with psychological research on the effects of sexism and gender stereotyping on women's choices, behavior and performance on various tests, and with how children learn to sort themselves into gender categories, starting at very young ages.

Those parts of the book fill in the background for the middle part, "Neurosexism," which discusses research into hormonally-driven "hard-wiring" of gendered interests, behaviors and aptitudes. (It's in this part of the book that she tackles the prenatal-testosterone literature). While she does offer some critique on methodological grounds, her biggest beef is with popularizers who extrapolate universal truths from ambiguous results derived from very small, restricted samples of people.

An example:

[W]hen I decided to follow up [Louann] Brizendine's claim that the female brain is wired to empathize, it nonetheless proved to be an exercise that turned up surprise after surprise. I tracked down every neuroscience study cited by Brizendine as evidence for feminine superiority in mind reading. (No, really, no need to thank me. I do this sort of thing for pleasure). There were many such references, over just a few pages of text, creating the impression that it is no mere opinion, but scientifically established fact, that the female brain is wired for empathy in a way that the male brain is not. Yet fact-checking revealed the deployment of some rather misleading practices. For example, let's work our way through the middle of page 162 to the top of page 164 in her book. We kick off with a study of psychotherapists, which found that therapists develop a good rapport with their clients by mirroring their actions. Casually, Brizendine notes, "All of the therapists who showed these responses happened to be women." For some reason, she fails to mention that this is because only female therapists, selected from phone directories, happened to be recruited for the study.
...
A little later, readers are told that "brain-imaging studies show that the mere act of observing or imagining another person in a particular emotional state can automatically activate similar brain patterns in the observer --- and females are especially good at this sort of mirroring." Cited as support for this feminine superiority in emotional mirroring is a 2004 neuroimaging study by cognitive neuroscientist Tania Singer and colleagues, who compared brain activation when someone was either receiving a painful electric shock to the hand or was aware that a loved one was receiving the same painful electric shock to the hand. Singer and colleagues found that some brain regions were activated both by being shocked and watching someone else be shocked. If you think I'm going to be nitpicky about what any sex differences in activation in this study mean, you're wrong. Actually, the problem of interpretation is rather more basic. Only women were scanned.

Even when there aren't gross factual errors in the reporting of the research, Fine's inclusion of social- and developmental-psychology perspectives on gender --- how children learn it, how children and adults learn to change their behaviors, and their understanding of themselves, to fit into it --- makes it clear that whatever gendered differences do turn up on brain scans, they are as likely to be the effects of gender socialization as they are to be the underlying physiological cause of gender.

So, if we're not "hard-wired" by means of prenatal and pubertal hormone surges into immutable, characteristic and complementary "male" and "female" selves, what are we? Are we just blank slates, onto which society can write whatever it likes? Is there no such thing as human nature at all?

That's the alternative vision most commonly invoked in these debates: if you don't accept the idea that gender is hard-wired, you must be an environmental determinist who doesn't believe people are born with anything at all in their heads.

Luckily for us, this isn't a binary, and we don't have to choose between nature and nurture.

Here's Fine again, this time from the Epilogue of her book:

The fluidity of the self and the mind is impressive and is in continual cahoots with the environment. When social psychologists discover, for example, that mere words (like competition), everyday objects (like briefcases and boardroom tables), people, or even scenery can trigger particular motives in us, or that similar role models can seep into our most private ambitions, it makes sense to start questioning the direction of causality between gender difference and gender inequality. We are justified in wondering whether, as gender scholar Michael Kimmel suggests, "gender difference is a product of gender inequality, and not the other way around."

Nor is gender inequality just a part of our minds --- it is also an inextricable part of our biology. We tend to think of the chain of command passing from genes, to hormones, to brains, to environment. (As biologist Robert Sapolsky describes this common misconception, "DNA is the commander, the epicenter from which biology emanates. Nobody tells a gene what to do; it's always the other way around.") Yet most developmental scientists will tell you that one-way arrows of causality are just so last century. The circuits of the brain are quite literally a product of your physical, social, and cultural environment, as well as your behavior and thoughts. What we experience and do creates neural activity that can alter the brain, either directly or through changes in gene expression. This neuroplasticity means that, as [neuropsychologist Anelis] Kaiser puts it, the social phenomenon of gender "comes into the brain" and "becomes part of our cerebral biology."

As for hormones that act on the brain, if you cuddle a baby, get a promotion, see billboard after billboard of near-naked women, or hear a gender stereotype that places one sex at a higher status than the other, don't expect your hormonal state to remain impervious. It won't. "Even how we behave or what we think about can affect the levels of our sex hormones," point out Gene Worship authors Gisela Kaplan and Lesley Rogers. This continuous interplay between the biological and the social means that, as Anne Fausto-Sterling has put it, "components of our political, social, and moral struggles become, quite literally, embodied, incorporated into our very physiological being."

And so, when researchers look for sex differences in the brain or the mind, they are hunting a moving target. Both are in continuous interaction with the social context. Some researchers have even started to investigate how the brain, or hormones, respond differently while doing stereotyped tasks, depending on whether gender stereotypes are made salient. And gender differences in the mind can shift from moment to moment: for example, as stereotype threat is created or dispersed, or self-identity changes. But also, our actions and attitudes change the very cultural patterns that interact with the minds of others to coproduce their actions and attitudes that, in turn, become part of the cultural milieu: in short, "culture and psyche make each other up." When a woman persists with a high-level math course or runs as a presidential candidate, or a father leaves work early to pick up the children from school, they are altering, little by little, the implicit patterns of the minds around them. As society slowly changes, so too do the differences between male and female selves, abilities, emotions, values, interests, hormones, and brains --- because each is inextricably intimate with the social context in which it develops and functions.
...
Our minds, society, and neurosexism create difference. Together, they wire gender. But the wiring is soft, not hard. It is flexible, malleable, and changeable. And, if we only believe this, it will continue to unravel.

This closing statement encapsulates what I like so much about this book; it brings feminism, sociology, and a more accurate, more nuanced understanding of human biology together to give us a broader view of what gender is --- or at least how many different things, over a person's whole lifetime, go into creating gender.

For some other reviews of this book, see Neuroskeptic*** and Echidne of the Snakes (Part 1, Part 2, Part 3).

*I was also given Rebecca M. Jordan-Young's Brain Storm: The Flaws in the Science of Sex Differences, which covers similar ground --- both books poke and prod at the conventional wisdom that sex hormones shape "male" and "female" brains before birth, and that masculine and feminine behaviors, interests and life paths are the inevitable outcomes of these two different types of brain. I haven't finished reading Brain Storm yet, but I will probably also review it here when I do.

**Another of their books, not cited in Fine's book, refers in its title to a particularly stubborn gender stereotype that drives many feminists --- particularly sex-positive feminists --- absolutely batty: Why Men Want Sex and Women Need Love. As if no woman has ever been horny, or no man ever wanted to be loved!

***Who is cited as a source twice, and quoted once, in this book!

Fetal Testosterone and Autistic Traits - Part V(a): More About Visuospatial Abilities

(An addendum to my earlier post on this topic)

Looking back at this article (full text here), I notice something I didn't write about in my earlier (as yet unpublished) post about it --- one of the things its authors were testing for, looking to see if it had any relation to how much testosterone they found in their study participants' mothers' amniotic fluid, was IQ (measured using the Wechsler Abbreviated Scale of Intelligence, or WASI).

More importantly, the researchers also tracked their subjects' scores on one particular subscale of the Wechsler test --- Block Design --- which has been shown over and over again to be something autistic people are very, very good at.

Not only are we better, overall, than non-autistic people are at this task, we also score much higher on it than we do on any other subscale of a Wechsler IQ test.

Our scores, when you plot them across all the different subscales, tend to show this characteristic pattern, of a valley on the (verbal) Comprehension subscale and a very high peak on the Block Design subscale:

(Image adapted from Figure 1 in Dawson et al., 2007; each square along the line represents a different subscale of the Wechsler Intelligence Scale for Children - Third Edition)

Here is another image, from a much older study, showing the difference between the distribution across the different subscales of a Wechsler test of autistic and non-autistic test-takers' scores.

(Figure 5, in Shah and Frith, 1993; both solid lines represent groups of autistic children --- the line connecting unfilled circles represents autistic children with high overall IQs, while the line connecting darkened circles represents autistic children with low overall IQs. Dotted lines represent various non-autistic groups: children with intellectual disability but not autism, children without disabilities, and teenagers without disabilities)

The peaked shape is present in both the low-overall-IQ and high-overall-IQ autistic groups, while both the low- and high-IQ controls' scores are more or less the same across all the subscales.

So, if more testosterone in the womb ---> autistic-like brains, you would expect 1) boys to score higher than girls on this task, 2) boys to show greater disparity between Block Design scores and other scores, 3) both absolute and relative Block Design scores to correlate with fetal testosterone within each sex.

As raw scores for each subscale of the WASI were not given in Auyeung et al., 2009, I can't tell anything about whether their subjects' Block Design scores were particularly high relative to the other subscales.

However, I can tell you that there were no sex differences on Block Design --- boys' average score was 19.14 to girls' 16.26, but the standard deviation for both sexes is probably somewhere between 9.5 and 10*, making the difference between the sexes a little less than one-third of a standard deviation, and thus not statistically significant.

Also, within each sex, amniotic testosterone had no relationship to any of the IQ measures the researchers reported --- not full-scale IQ, not verbal IQ, not performance IQ and not the Block Design subscale of performance IQ.

So, this cognitive ability characteristic of autism doesn't seem to vary with sex or with androgenicity.

*Standard deviations are only given for boys and girls separately; for boys, it is 9.41; for girls, 10.08. There are 43 boys and 31 girls in this study population.

Auyeung, B., Baron-Cohen, S., Ashwin, E., Knickmeyer, R., Taylor, K., & Hackett, G. (2009). Fetal testosterone and autistic traits British Journal of Psychology, 100 (1), 1-22 DOI: 10.1348/000712608X311731

Dawson, M., Soulieres, I., Ann Gernsbacher, M., & Mottron, L. (2007). The Level and Nature of Autistic Intelligence Psychological Science, 18 (8), 657-662 DOI: 10.1111/j.1467-9280.2007.01954.x

Shah, A., & Frith, U. (1993). Why Do Autistic Individuals Show Superior Performance on the Block Design Task? Journal of Child Psychology and Psychiatry, 34 (8), 1351-1364 DOI: 10.1111/j.1469-7610.1993.tb02095.x

What Would You Tell a Teenage Girl with Autism?

Sharon daVanport's blog, Spectrumy, has this guest post from Shana Nichols, a psychologist who specializes in helping girls with autism cope with the social and emotional challenges of adolescence:

I am currently writing a companion book [to her earlier work, Girls Growing Up on
the Autism Spectrum] for pre-teen and teen girls themselves to read titled A Girl's Guide to Growing Up on the Autism Spectrum. My co-author, Brigid Rankowski, is a college student with AS. This book is under contract with Jessica Kingsley Publishers, and at this time we are looking for short contributions from girls and women.

If you (as an adult on the spectrum) or your daughter would be interested in sharing an experience, or advice related to growing up as a female with an ASD, I would love to hear from you. We are looking for 50-200 word narratives about any topic related to growing up. Some examples include:

• What it's like being a girl/woman with an ASD
• Puberty
• Having your period; gynecological exams
• Getting a first bra
• Friendships and mean girls; bullying; fitting in
• Eating issues
• Self-esteem and feeling good about yourself
• Being true to who you are
• Mood and anxiety
• Sexuality
• Relationships and dating
• Media, popularity
• Life goals and pursuing your dreams
• Special interests

We are also interested in poetry and possibly art work.

I like this project --- especially when we're that young, there's so much we know but can't articulate about how we're different, particularly the growing suspicion that certain things that are very, very hard for us are as simple as breathing to most people, and thus that most people can't even tell we're struggling, because what could we possibly be struggling with? It might be helpful to have stuff written down by adults who've already figured out ways to cope with some of the really thorny, hard-to-name problems like inertia, executive dysfunction, sensory hypersensitivities, etc. Even if the solutions they describe aren't practical for the young person reading the book, they can at least show the essay to their parents and say, "See this? The problem she talks about? I have it, too."

I know I had to wait a very long time before I could describe most of the things that now seem to matter a great deal to me, and greatly affect my day-to-day welfare.

I'm not sure to what extent a guidebook written by autistic adults/other adolescents would've helped me, though, because many of my biggest problems either had little or nothing to do with autism (example: chronic, recurring nausea and other gastrointestinal issues) or my solutions to the problem required a freedom to arrange my life around my body's own needs and rhythms that most teenagers don't have (example: if I can wait a few hours before eating anything, I'll have a lot fewer problems than if I have to wake up, eat, and rush out the door). (As you can see from my choice of examples, sometimes both of those things are true at the same time).

I would also not have much, if anything, to say about many of the topics on their sample list, as many of them did not apply to me. I don't remember puberty --- at least, I don't remember menarche, and the other changes were gradual (and slight!) enough to be non-issues.

Similarly, getting a bra was not a memorable occasion for me; I wore training bras, and only ever "graduated" to sports bras.

Mean girls? What mean girls? The bullies I worried about were all boys, and I wasn't worried about being ostracized or gossiped about so much as I was worried about physical violence. (That never actually happened, but it's always a possibility when you are one gawky social outcast and your harassers are many teenage boys. I feared it, at any rate).

I was also so socially obtuse at that point in my life that many characteristic "mean girl" tactics would probably have been wasted on me.

However. There is one thing that could have made a world of difference if I'd been explicitly told this sometime during middle school, or at the beginning of freshman year of high school: that it's okay to say no to any form of sexual contact just because you don't want to do it. In other words, I wish I'd been given a Talk about consent. I wish it very much, because my not-rape in high school happened because I didn't know I could say no, so I allowed all sorts of stuff I didn't enjoy to be done to me by a boy I didn't even like.

I might write something about that, if I can get it short enough, coherent enough, and I don't think I'd be being too much of a Debbie Downer sending it in.

Fetal Testosterone and Autistic Traits - Part V: Visuospatial Abilities

EXECUTIVE SUMMARY: Researchers looking into the separate questions, "How do male and female minds differ?" and "How do autistic people differ from non-autistic people?" have discovered --- independently of each other --- an assortment of cognitive strengths peculiar to each of the groups being studied. Now that Simon Baron-Cohen has floated the idea that autism is just an extreme version of the normal male brain, it would make sense to check if the cognitive strengths of autistic people, and of all men, really do overlap, and whether prenatal testosterone exposure seems to play any role in the development of any of those aptitudes.

One recent study (Falter et al., 2008) compared groups of autistic and typically developing schoolchildren on three visual/spatial tasks that normally show a male advantage: mentally rotating three-dimensional objects, positioning a cursor over a moving image, and spotting a shape hidden somewhere in a larger pattern or line drawing, or "figure disembedding". They also measured the children's second-to-fourth digit ratios, as an indicator of prenatal testosterone exposure.

Their results were not consistent with what they predicted based on the extreme-male-brain theory of autism: the autistic children did better at figure disembedding, worse at targeting the moving image, and were slightly faster (but not more accurate) at mental rotation. On further analysis, though, they seemed to be faster at different parts of the (complex, multi-step) mental-rotation process than non-autistic men seem to be. The researchers were able to break down the results of the mental-rotation task into "rotational" and "non-rotational" components --- that is, to separate the actual visualization of the object rotating from the other factors, like comparing the rotated object in your head to the one shown on the screen and deciding whether they are the same. Autistic people seem to be faster at the non-rotational parts of this process, while non-autistic, male people seem to be faster at the rotational part. So, different cognitive skills underlie the two groups' respective advantages at the same complex task.

Finally, testosterone seemed to play no role whatsoever in predicting a child's success at either mental rotation or figure disembedding; the only task that showed a relationship between digit ratios and performance on that task was targeting, which 1) was harder for the supposedly "hyper-masculine" autistic boys, and 2) was easiest for the boys with middling digit ratios --- the ones with very low, "masculinized" digit ratios performed worse, as did the ones with high, "feminized" digit ratios. There were also no group differences in digit ratio between autistic and non-autistic boys.

________________________________________

The term "visuospatial abilities" covers a lot of ground, and might include different skill sets depending on where and how it's being used.

For example, one of the most-studied (and most reliably replicated) cognitive differences between the sexes is a male advantage in the ability to rotate three-dimensional images on one's head; other spatial skills that tend to show a male advantage are aiming, predicting a projectile's trajectory . If autism is the same thing as having an "extreme male brain," you would expect autistic people to do better at these tasks than non-autistic people of their same gender.

There is also a well-established constellation of visual and spatial skills that autistic people tend to be better at than non-autistic people: the Block Design subscale of the Weschler intelligence tests, spotting a shape hidden inside a larger pattern (i.e., disembedding a figure), distinguishing a target figure from a crowd of "distractor figures" that are similar but not identical to the target, and reproducing a distorted or impossible image. It would be equally instructive, as far as investigating the extreme-male-brain hypothesis is concerned, to look for sex differences in how non-autistic people do on these tasks; you would also want to look for a relationship between those abilities and prenatal testosterone exposure. If the autistic cognitive style is essentially the same as the masculine one, you would predict exposure to higher levels of testosterone in utero would correlate with higher scores on the Block Design, faster and more accurate performance on visual-search tasks (like the Embedded Figures test or the tasks described in this study), and greater accuracy on drawing tasks, like the perspective-drawing task described here or the shape-drawing task described here (PDF).

One relatively recent study, carried out by Christine Falter, Kate Plaisted and Greg Davis and published in the Journal of Autism and Developmental Disorders, directly addresses the prediction I made in the second paragraph. Those researchers identified three visuo-spatial tasks that usually show a male advantage (or correlate with prenatal testosterone exposure, or both) --- mental rotation, targeting and figure-disembedding --- and tested a group of 28 autistic schoolchildren (27 of whom were boys) and a group of 31 typically-developing children matched for age, sex and nonverbal IQ on those tasks. They also measured the children's second-to-fourth digit ratio, as an indirect measure of prenatal testosterone exposure.

(Sample image from the Embedded Figures Test)

They found no significant differences between the autistic children and the typically-developing children in terms of digit ratio; depending on how the study participants were grouped (because each skill was tested in a differently-sized subset of the total study population), either the autistic half or the neurotypical half of a given subgroup might have slightly higher 2D:4D. These differences were so slight as to be statistically insignificant, regardless.

Overall, the autistic children did better at both mental rotation of 3-D objects (measured by having the children turn a computer-generated image of a solid to match the view of that solid the computer showed them) and figure disembedding than the typically-developing children; they were both faster and more accurate at these tasks. (Although, for the mental-rotation task, the difference was very slight). However, they performed worse than the typically-developing children at the targeting task, in which they had to position a cursor over an image that would appear at random points within certain regions of the computer screen*. Also, the mental-rotation results are a bit more complicated than just looking at the mean reaction times and accuracies of both groups would lead you to believe. The study authors did a linear regression of each of those two outcome variables with the degree of rotation (i.e., how far from its original position did the participants have to rotate the object?), which apparently allowed them to separate out the different cognitive processes used in mental rotation:

Across participants, the degree of rotation showed a strong linear relationship with reaction time, RT (R = .99, F(1,3) = 227.88, p = .001), and accuracy scores, ACC
(R = .98, F(1,3) = 59.84, p = .004). Accordingly, consistent with previous studies of mental rotation, RT and ACC were each regressed linearly against angle of rotation for each participant, to yield a rotation slope and an intercept. The slope for each participant indexed the speed with which they mentally "rotated" objects in degrees per second. The intercept yielded by these regressions indexed non-rotational aspects of performance, presumably related to the speed with which participants mentally compare three-dimensional objects as well as decision making and response variables.

Only the linear regression for reaction time showed any difference between the autistic and typically-developing groups, and there the difference was only in the intercept; the slopes of the two groups' lines were more or less the same.

(Figure 1, in Falter et al., 2008 --- graph showing the linear relationship of degree of rotation with reaction time)

Since two of the three authors of this paper (Falter and Davis) had also been involved in a similar study comparing men and women, using the same linear-regression method in their analysis of their results, they were in a position to notice differences between the men's results in the 2006 study and the autistic children's results from the 2008 study.

While both of the studies found overall differences that seem to lend support to Baron-Cohen's hypothesis --- men outperformed women, and autistic boys** outperformed typically-developing boys --- the linear regressions of both sets of data revealed different factors contributing to each better-performing group's advantage: while the autistic group in Falter et al. (2008) seemed to be better at the non-rotational aspects of this task, the male group in Falter et al. (2006) was faster at performing the rotations themselves. (In other words, if you were to compare the graphs made of the linear regressions of their results, the graphs in the 2006 study would have different slopes, while the graphs in the 2008 study have about the same slope, but different intercepts).

(Figure 2, in Falter et al., 2008 --- graph showing relationship of second-to-fourth digit ratio to reaction time on Targeting task)

Neither the mental-rotation task nor the figure-disembedding task showed any relationship to digit ratio; however, there was a quadratic relationship between 2D:4D and reaction time on the targeting task, with children having both very high (above 1.0) and very low (below 0.90) digit ratios taking longer to position the cursor correctly than their peers with mid-range digit ratios.

An older study, carried out in 1992 by Jo-Anne Finegan, G. Alison Niccols, and Gabriel Sitarenios, compared testosterone levels in the amniotic fluid of women who had undergone amniocentesis at Toronto General Hospital during the mid-1980s with those women's children's later results (at age four, in this study) on a wide range of cognitive tests.

The visuospatial tasks included in this study were fairly similar to the ones Falter, Plaisted and Davis used: there was a figure-disembedding task (the Preschool Embedded Figures Test, in which a triangle is hidden somewhere in various line drawings of familiar objects), a block-building task, in which the person giving the test builds structures of varying complexity out of 1-inch cubes, and the child is supposed to build the same thing. It's not the same as the Block Design test, but it seems pretty close to it to me. The one thing Falter et al. test that Finegan et al. do not is targeting, and Finegan et al. test a few things Falter et al. don't: picture-puzzle solving (which I guess is also analogous to Block Design) and geometric-form copying (analogous to the drawing tasks I mentioned above, in the paragraph about autistic people's visuospatial strengths).

(Sample image from the Preschool Embedded Figures Test)

That study found no significant sex differences in any of the skills being investigated; it also found no relationship between prenatal testosterone and performance of three of the four tasks I describe above --- figure disembedding, puzzle solving and shape drawing were all independent of prenatal testosterone exposure in both sexes. For girls, there was a significant negative relationship between prenatal testosterone and scores on the block-building task --- the higher female scorers on this test tended to have lower levels of prenatal testosterone exposure than their lower-scoring peers; for boys, there was a small trend in the opposite direction --- with high scorers tending to have higher prenatal testosterone levels --- but that relationship wasn't statistically significant.

Falter et al.'s results tell me that the area of overlap between 1) the things men are usually found to better at than women, and 2) the things that autistic people are usually found to be better at than non-autistic people, within the larger domain of visuo-spatial skills, is fairly small. Also, the two "masculine" skills that autistic people tend to do better at --- figure disembedding and mental rotation --- are not at all correlated with an indirect measure of prenatal androgen exposure.

Because there is some uncertainty around the use of digit ratios as a marker for prenatal testosterone exposure, I wanted to find a study of similar cognitive abilities that measured that variable directly. Finegan et al.'s study was the only one I could find that did this, even though it was old and didn't have any autistic participants. Their results showed that prenatal testosterone has no effect on young children's performance at most visuospatial tasks, and, on the tasks it does influence, it seems to affect boys and girls differently, with higher levels of testosterone exposure boosting boys' scores but lowering girls'.

*It doesn't surprise me at all that autistic people would be slower at that, given our difficulties with motor planning. Even apart from that, some studies have found that we are not as good as neurotypical people in tracking moving visual stimuli --- see this review (full text here) for more detail.

**I use "boys" here because there were a total of two girls --- one in the autistic group, and the other in the control group --- in this study population of fifty-nine children.

Sources:
Falter CM, Plaisted KC, & Davis G (2008). Visuo-spatial processing in autism--testing the predictions of extreme male brain theory. Journal of autism and developmental disorders, 38 (3), 507-515 PMID: 17674175

Finegan, J., Niccols, G., & Sitarenios, G. (1992). Relations between prenatal testosterone levels and cognitive abilities at 4 years. Developmental Psychology, 28 (6), 1075-1089 DOI: 10.1037/0012-1649.28.6.1075

Voyer D, Voyer S, & Bryden MP (1995). Magnitude of sex differences in spatial abilities: a meta-analysis and consideration of critical variables. Psychological bulletin, 117 (2), 250-270 PMID: 7724690