Friday, August 3, 2012

Two Myths and Three Facts About the Differences in Men and Women's Brains

There are a handful of myths in the world (well, mostly on the internet so people think they are true) about supposed differences between men and women, especially concerning our brains. This brief article from Christian Jarrett, Ph.D (editor of the British Psychological Society's Research Digest blog and staff writer on their magazine The Psychologist) at his Psychology Today blog, Brain Myths, tries to clear up some misunderstandings.

There is a related series of myths about language use in men and women, many of them created and/or perpetuated by John Gray, the &%$@# behind the whole men are Martians and women are Venusians stupidity. Dr. Yvonne K. Fulbright debunked this nonsense in a column at Huffington Post last year - I have included it below.

One of the really stupid myths that won't go away (I've seen it in academic gender studies articles) is that women use way more words per day than men. Louann Brizendine, author of  The Female Brain, is often quoted on her assertion that women speak an average of 20,000 words per day, while men speak a paltry 7,000 words per day (but it's only sloppy research on her part, the myth goes back 15 or more years). An article from Scientific American dispels the myth emphatically.

As you may notice, this is one topic that infuriates me - Gray and others generate fortunes making this stuff up and people are so uneducated in science and psychology that they believe it. But what the hell, they also believe that John Gray is an actual PhD, when he doesn't even hold a master's degree from an accredited school.

Gender brain differences are real, but we should interpret them with caution

MYTH 1: Women’s brains are more balanced

"It is true that men use one side of their brain to listen while women use both sides," says the Suite 101 website with misplaced confidence. 

This is a variation of the popular idea found in many books and websites that men depend more than women on one hemisphere or the other for particular functions (especially language), and related to this, that women have a chunkier corpus callosum—the bridge of neurons that connects the two brain hemispheres.

One source of the myth is a theory proposed by the late US neurologist Norman Geschwind and his collaborators in the 1980s, that higher testosterone levels in the womb mean the left hemisphere of male babies develops more slowly than females, and that it ends up more cramped. But the Geschwind claim is not true: John Gilmore and his team scanned the brains of 74 newborns and found no evidence for smaller left hemispheres in male babies compared with females. Also debunking the idea of greater lateralisation in male brains, a meta-analysis by Iris Sommer and her colleagues of 14 studies, involving 377 men and 442 women, found no evidence of differences in language lateralisation between the sexes. On the thickness of the corpus callosum, Mikkel Wallentin reviewed the evidence in a 2009 paper, including post-mortem and brain imaging studies. “The alleged sex-related corpus callosum size difference is a myth,” he wrote. 

FACT 1: Men’s brains are bigger

Men do have bigger brains than women, even taking into account their larger bodies. This has been documented time and again. To take just one example, Sandra Witelson and her colleagues weighed the brains of 58 women and 42 men post-mortem and found the women’s were 1248 grams on average, compared with 1378 grams for the men. Note, there’s an overlap between the sexes, so some women will have larger brains than some men. A Danish study of 94 brains published in 1998 estimated that the larger male brain volume translated into an average 16 per cent greater amount of neurons in the neocortex of men versus women.

FACT 2: There are sex differences in the size of individual brain structures

The hippocampus, a structure involved in memory, is usually larger in women; the amygdala, a structure involved in emotional processing, is larger in men. It’s also true that the cortical mantle (made up of grey matter) is thicker in women, and that women tend to have a higher ratio of grey to white matter (white matter being the kind of brain cells that are insulated). However, it’s important to note that these differences may have more to do with brain size than with sex—in other words it could be that smaller brains tend to have a higher ratio of grey matter, and it just happens that women tend to have smaller brains.

MYTH 2: Sex-related brain differences explain behavioural differences between the sexes
According to John Gray, author of Why Mars and Venus Collide, men are prone to forgetting to buy the milk because of their more localised brain activity (as quoted by Cordelia Fine). 

It’s tempting to see the brain differences between the sexes, mythical or otherwise, and think that they explain behavioural differences; such as men’s milk amnesia, their superiority on mental rotation tasks or women’s advantage with emotional processing. In fact, in many cases we simply don’t know the implications of the sex-related brain differences. It’s even possible that brain differences are responsible for behavioural similarities between the sexes. This is known as the “compensation theory” and it could explain why men and women’s performance on various tasks is similar even whilst they show different patterns of brain activity. Bearing this in mind, readers should treat with extreme scepticism those evangelists who draw on supposed sex-related brain differences to support their claims about the need for gendered educational practices.

It’s also important to remember that behavioural differences between the sexes are rarely as fixed as is often made out in the media. Cultural expectations and pressures play a big part. For instance, telling women that their sex is inferior at mental rotation tends to provoke poor performance; giving them empowering information, by contrast, tends to nullify any sex differences. Related to this, in countries that subscribe less strongly to gender-stereotyped beliefs about ability, women tend to perform better at science. These kind of findings remind us that over-simplifying and over-generalising findings about gender differences risks setting up vicious self-fulfilling prophesies, so that men and women come to resemble unfounded stereotypes

FACT 3: Sex-related brain differences matter

Whilst we should be cautious about how we interpret sex-related brain differences (Cordelia Fine reminds us that “the male brain is like nothing in the world so much as a female brain”), it’s important not to take political correctness too far and deny that differences do exist. The neuroscientist Larry Cahill makes this point in his 2006 paper “Why sex matters for neuroscience”, in which he reviews many of the sex-related brain differences. Furthering our understanding of sex-related brain differences could help shed much needed light on conditions like autism and depression that tend to be found much more often in men and women, respectively.

Further reading—do read Delusions of Gender, The Real Science Behind Sex Differences by Cordelia Fine; Pink Brain, Blue Brain by Lise Eliot; and Brain Gender, by Melissa Hines (and Deborah Cameron's The Myth of Mars and Venus). Avoid Why Men Don't Listen and Women Can't Read Maps by Barbara and Allan Pease; Why Mars and Venus Collide, by John Gray; and The Female Brain by Louann Brizendine (also avoid The Male Brain).

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Male-Female Communication: Debunking the Mars-Venus Myth

Dr. Yvonne K. Fulbright - Sexologist, Sexuality Educator, Author
Posted: 02/13/11
Go to a popular news site like The Huffington Post and plug the term "mars venus" into the search field. At least a dozen blogs come up, making reference to men and women speaking "different languages." The dogma of John Gray's "Men Are from Mars, Women Are from Venus" is everywhere, and it appears positioned to get even bigger with Summit Entertainment reportedly acquiring the film and TV rights to Gray's franchise.

Why should we care? According to scientific research and Deborah Cameron's "The Myth of Mars and Venus," Gray has "he" versus "she" communication all wrong.

Turn to any Mars/Venus-based resource, and you'll hear that men and women are fundamentally different in the way they use language to communicate. The supposed differences between the sexes, they say, are due to nature, not nurture; humans are hard-wired so that females excel in verbal tasks -- explaining why she wants to talk his ears off about feelings, needs and "where we're at," and why he is so turned off by such attempts.

Yet, as Cameron's book points out, the data on gender communication differences indicates otherwise:

Myth: Females talk more than males.
Fact: A review of 56 research studies by Deborah James and Janice Drakich found 34 that reported that men talk more than women, with females talking more than males in only two studies. A more recent University of Arizona study in the journal Science reported that both genders speak almost the exact same number of words daily (16,000).

Myth: Females are more verbally skilled than males.
Fact: While a 2005 meta-analysis of studies on gender differences in verbal/communicative behavior by Janet Shibley Hyde found a moderate effect size favoring women, it also revealed that there was a close to zero effect for reading comprehension, vocabulary and verbal reasoning.

Myth: Females seek to connect with others, while males use language with the intention of accomplishing things.
Fact: Studies by researchers Kathy O'Leary and Pamela Fishman indicate that the genders may differ in patterns because they're engaged in different activities or are playing different conversational roles. These differences don't necessarily appear when males and females are doing the same things or playing same roles.

Myth: Females use language cooperatively, because they prefer harmony and equality.
Fact: Hyde's meta-analysis indicated that there was a moderate effect size for women when it came to smiling during conversations. There was also a small effect size for them when it came to speech production, talkativeness, affiliative speech and self-disclosure. Still, who's to say that this isn't due to nurture and not nature, especially when there's no data to support the former?

Myth: Males are more direct and not as polite in communicating.
Fact: Hyde's meta-analysis showed that there was only a small effect size favoring males when it came to conversational interruption and assertive speech. There's actually more variation in communication within each gender than there is when you compare any differences between men and women.

As the research shows, the language skills of men and women are nearly identical. Yet the myths they debunk are still used to support the premise that the genders are regularly misunderstanding each other due to mere genetics. With the media fully on-board the Mars/Venus bandwagon, "failure to communicate" across genders has been used to explain everything from why men don't take out the garbage upon request to why a rapist didn't understand his victim's attempts to resist. Ultimately, both genders suffer.

Men are sized up as inarticulate, aggressive Neanderthals, incapable of feeling emotions and being sensitive. Women are criticized for being overly cooperative and caring doormats. Such discrimination shapes beliefs and influences actions, both personally and professionally.

When it comes to mating, he is supposed to be allowed to "go into his cave" when times get tough or when there's something that needs to be done or discussed. Maintaining the relationship becomes her responsibility, requiring that she accommodate his communication style.

When it comes to the job market, females are supposedly better at jobs involving communication and empathy, while men are supposed to be better suited for analyzing complex systems. She is favored when it comes to jobs involving teaching, nursing and counseling. He is considered better suited to occupy positions of power and authority, as in engineering, banking and politics.

Anybody who is truly enlightened and who knows anything about males, females and relationships knows that that is all wrong. Still, the Mars/Venus phenomenon continues to make millions. When will we let science command the "he versus she" communication conversation?

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1 comment:

DMG said...

As a school teacher I am always fascinated by this topic. Last year I had to endure a presentation by the Gurian Institute (ARGH!). What has drawn more of my focus however, is the connection between shame and the development of gender differences/stereotypes and how they play out in things such as stereotype threats thus impacting performance. Books such as Kaufman's remarkable book, Coming Out of Shame, and more recently Steele's, Whistling Vivaldi shed light on this phenomena.