With Christmas eve looming, trust me when I tell you that this article will provide vital information for any of you who will be assembling large gifts to put under the tree or for yourself after the festivities are concluded. There has long been a belief that there’s a difference between the brains of men and women which somehow makes the boys better at spatial configuration and visualizing three dimensional figures than the girls. Is it true or is this just an artifact of gender biased testing from the bad old days? The Washington Post reported this week on a fascinating test designed to solve this riddle by allowing men and women to assemble IKEA furniture both with and without the directions. The results were… mixed.

The study asked 40 men and 40 women, all university-aged, to put together an IKEA kitchen cart by themselves. Some people got copies of the assembly manual. Others only had a drawing of the final cart.

With the instruction manual, men and women assembled the cart in about the same amount of time on average, and at roughly the same level of quality. Both genders took around 23 minutes to put the cart together, and on average they only made a few small mistakes, like forgetting some screws, for instance.

For those without the step-by-step diagrams, though, the difference between genders was dramatic. Men took around 24 minutes on average, but women took over 28 minutes, a difference of over 20 percent. Had the researchers not cut people off after 30 minutes, the gender disparity might have been even wider. Women were also far more likely to have major problems with their kitchen carts, like missing a shelf or a railing.

I’d always thought that the whole “women can’t do this sort of stuff” meme was based on anecdotal evidence at best. Personally, I find that I’m much better at assembling products like this first thing in the morning and not after the Christmas Eve party and too many glasses of eggnog. And for the record, I should point out that this is a completely biased, false theory put forward by men who don’t have any real appreciation for the talents and abilities of women.

(My wife’s taken to reading the blog lately, though I still wont’ give her a comment account. That’s enough now, sweetie. You can stop reading.)

But seriously, this seems like one of those old wives’ tales (pardon the phrase) which may be rooted in some truth. Why would males be better at finding the right pieces, putting the fasteners in the correct holes and pushing tab A into slot C? Discover Magazine published one of many studies which have been done on the subject (though not specifically with furniture) and found that there’s some truth to it, but it’s complicated.

First, there’s the idea that men are more variable in their intelligence, so there are more very smart men, and also more very stupid ones. This averages out so the mean is the same.

Second, there’s the theory that men are on average better at some things, notably “spatial” stuff involving the ability to mentally process shapes, patterns and images, while women are better at social, emotional and perhaps verbal tasks. Again, this averages out overall.

While I’d heard this many times in the past, I’d never seen it explained that way. If their long term test results are accurate, the average woman and the average man are, for the most part, essentially equal in IQ and in the ability to perform these spatial tasks. But the problem comes in with the fact that the ladies tend to be far more homogeneous in their brain structure and function while the gents vary wildly from one to the next. The short version of all that is that there wind up being some men who are a lot smarter and better at certain things but they’re balanced out by the number of us that are complete tools with the mental acuity of a box of rocks. So you’ll find some number of guys who can do massively complex differential equations in their heads at a level that more of the girls won’t manage, but your at least as likely to find a huge batch of us who couldn’t figure out how much to tip the waitress at the end of the meal. (Is that why guys tend to be far, far better tippers?)

Long story short, if you’ve got some presents which require assembly, the ladies now have the perfect excuse to insist that your guy put it together while you get some extra sleep. It’s not discrimination… it’s just science.