kitchen table math, the sequel: off-topic: a sex difference I had never heard of

Friday, March 9, 2012

off-topic: a sex difference I had never heard of

Reading The role of the orbitofrontal cortex in normally developing compulsive-like behaviors and
obsessive–compulsive disorder
by David W. Evans, Marc D. Lewis, and Emily Iobst, I came across mention of a sex difference so striking I had to post:
[H]man studies show gender differences in callosal axons projecting from the OFC -orbitofrontal cortex]: men attain maximal callosal size in this region at age 20, well ahead of women who do not attain it until 40-50 years (Cowell, Allen, Zalantino, & Denenberg, 1992).
We're talking about a 20-year gender gap in development?

Twenty or 30?


And how is it nobody's ever heard about it?

It's not like the orbitofrontal cortex is an insignificant part of the brain, or anything.


ChemProf said...

Why hasn't anyone heard of it? Because it violates the first rule of sex difference research -- such research is only significant when it shows tiny differences or when it shows women are superior.

AmyP said...

Not sure what this part of the brain does, but could this be why a lot of women start hoarding during middle age?

Catherine Johnson said...

chemprof----- I am LAUGHING.

I fear you are right.....

Catherine Johnson said...

Do women start hoarding in middle age specifically?

Catherine Johnson said...

Here's the puzzling part (one of the puzzling parts): boys develop OCD much earlier than girls.

(The OFC is heavily involved in OCD -- and also in addiction.)

Catherine Johnson said...

I'm wondering whether this factoid has to do with the 'mean girls' phenomenon --- and/or with men's ability to 'compartmentalize.'

I've spent my entire adult life seeing 'compartmentalization' characterized as a bad (or at least not good) thing .... but that never made sense to me. I've always thought: hmmmm. Compartmentalization. I'd like to do more of that.

Catherine Johnson said...

I don't think anyone really knows what's going on in the OFC at this point, but people DO know what it looks like when you have brain damage to the OFC.

I read a terrific description today: people with damage to OFC are completely unimpaired cognitively but can no longer make everyday decisions.

Phineas Gage is the most famous example, but the man in Descartes' Error is incredible.

I think he may have been an attorney. He had some kind of brain damage (I don't remember whether it was an accident or a stroke), and after that he passed basically every neuropsychological test the doctors had -- and he was profoundly dysfunctional. I think he stopped being able to hold a job, he got divorced, he married a prostitute (then divorced the prostitute five seconds later), lost all his money --- he was a wreck.

Also, he couldn't do simple things like make a decision about which restaurant to go to.

Another interesting things: 2-year olds have a lot of OCD-like symptoms --- and I **think** this is before the OFC comes online. (I may be misremembering that second part.)

Something has gone wrong with the OFC in obsessive-compulsive disorder, and with addiction it sounds like maybe the OFC is damaged by continual usage of drugs, SO addiction, which is initially pleasurable, becomes compulsive.

Catherine Johnson said...

OFC seems to be critically important to shifting behavior when the rewards change. In simple experiments where you always pick "A" because "A" is associated with a reinforcer, then all of a sudden "B" is associated with a reinforcer, people with OFC damage can't shift (or take longer to shift.)

Animals, too.

Amy P said...

"Do women start hoarding in middle age specifically?Do women start hoarding in middle age specifically?"

I'm not sure about gender and hoarding, but it often seems to kick in in middle age (although there are younger hoarders). There's a very good book called "The Secret Lives of Hoarders" that you would like.

You're right about 2-year-olds and OCD-type behavior. I think I've also seen small children display hoarder-like behaviors that dissipate as they get bigger (thank goodness!).

Amy P said...

Here's a blog review I wrote of The Secret Lives of Hoarders.

Catherine Johnson said...

Thank you!
I remember finding a terrific blog on hoarding once....did I write about it here?
Can't remember what got me onto the subject --- serendipity, probably.
The blog was written by the girlfriend or wife of a man whose mother was a hoarder. (I can't remember if the mother had recently died; that may have been part of it.)
The son had some hoarding tendencies, too, and his efforts to clear out his mom's house were painful and challenging.

Catherine Johnson said...

btw, hoarding and OCD are separate things, apparently.

SteveH said...

There are other variables. Our high school just posted the top ten students of the senior class in their main hallway. They are all girls. Every year, the honor role lists are dominated by girls. Nurture? Nature? Societal expectations? Is this a problem? What, exactly, is the problem?

lgm said...

Does your high school use participation as a component of the grades? It was 1/3 of the qtr grade here until this year. The student would lose his points for the day for shouting out, coming in late, executive functioning deficits such as not being able to pull out the hw in the first 2 minutes, etc.