Dumb sells, first, because it's funny, whether it's the Keystone Kops, Dumb and Dumber, or birds taking revenge on humans in this Windex ad. But why dumb men? Why not dumb women?

Patrick Wanis ("A voice for women" according to Fox News) argues that advertisers portray men as incompetent in order "to appeal to women and to create a sense of female empowerment associated with the product – in the hope that women will then buy the product." He points to this Tide commercial, where a father's ineffectual attempt to stop his daughter from wearing a mini skirt is foiled by mom's (and Tide's) stain removing ability.

Wanis is correct in so far as some dumb men ads are indeed targeted towards women. I would divide these into two categories. The first is advertisements that tell women "you're smart enough to make this decision." These ads are for products that are not traditionally "feminine", but are now purchased by women in significant numbers - cell-phones, for example (see this rant inspired by Rogers mobile phone ads). I find these ads grating, but see that they might make some women feel superior.

The second category of female-targeted dumb men commercials, however, disempower women. They are part of a larger social trend towards seeing men and women as fundamentally, irreconcilably different. The message is simple: Face it, ladies, your man basically wants to be fed, lie around on the sofa, and go out and mess around with his buddies. He is what he is, and you can't change his basic nature. As books like The Man Whisperer explain, women can achieve happiness if they stop trying to be the leaders in the home, and instead use their love and respect to lift up their men. And Tide and a host of other products will be there -- to help women do laundry, cook dinner, clean the house, and generally take care of their hopeless idiot menfolk. The insult to men's intelligence in these commercials is obvious; the anti-feminist message is more subtle, but that makes it all the more dangerous. Me, I'll stick with a smart man who knows his way around a washing machine.

(I'm not alone. The Old Spice commercial featuring a not-dumb man has about 30 million hits on Youtube, the Tide ad mentioned here about 30 thousand.)

Yet many dumb men commercials are targeted specifically at men, such as this Diesel advertising campaign. These ads have a message, sometimes subtle, sometimes not: it's smart to be stupid. Why waste hours cooking a fancy breakfast, when you can mess around, have a good time, and fool everyone with Eggo homestyle frozen waffles?

The Sociological Images blog argues that these commercials reflect a larger social phenomenon: "a cluster of ideas related to intellectualism – liking school, studying hard, being smart, reading, and even caring about ideas – have become feminized." In other words, school is for girls and Asians. Real men, especially real white men, don't bother.

Like many stereotypes, it contains a grain of truth. In Canada in 2007/8, 58.5% of undergraduates were female. And there are large differences in educational attainment across ethnic groups. As a recent Statistics Canada study notes, "In 2006, university completion rates among 25- to-34-year-olds varied from 62% among children from Chinese families, to 17% among those from Portuguese families. The children of Canadian-born parents (the third-and-higher generations) registered a completion rate of 23%."

Yet the fact that boys are struggling in school makes dumb men ads even more pernicious - the message that stupidity is truly brilliant makes studying unappealing.

The defender of dumb men might reply "yes, but the world is still run by white men, that makes them fair game." I suspect that is the reason why advertisers choose white men to represent crooked immigration consultants, like this one featured in a Citizenship and Immigration Canada advertisement, or bankers who torment small children, like the one depicted in the Ally Bank commercials, who gives a young girl a bicycle, then won't allow her to ride it.

Yes, the people who run Canada are, disproportionately, white men. But white men are also well represented in prisons, on skid row, among the drug addicts on Vancouver's downtown east side. White men's fairly high average outcomes masks enormous variation within this demographic group.

Moreover, the world is changing. Canada's racist Chinese exclusion acts have long since been repealed. Although a recent paper by Pendakur and Pendakur finds that Canadian born Chinese men earn 8 percent less than men of British ethnicity, this is an all else being equal comparison. In terms of the raw earnings numbers, there is little difference - the average log wages of Chinese-Canadian men in 2005 was 10.62, of British origin men 10.63. The Asian American man in advertising is the trusted vet, the model minority "associated with affluence and professional status." The mystic master of martial arts. O.k., those are stereotypes too. But if you're a parent sitting watching TV with your son, would you rather he identify with a model minority image or a dumb guy image?

I have talked so far mostly about dumb guy ads, as these are by far the most pervasive. Yet some ads feature dumb women, for example, the Diesel campaign. From Marilyn Monroe to Married... With Children's Christina Applegate, there is one rule for dumb women jokes: the woman must be hot, and preferably blonde. Ads portraying dumb hot women are satisfying for two reasons. The first reason these ads appeal is pretty obvious. The second arises from the fact that beauty - or hotness - gives women power over men - they have something that men want. Desirable women are shown as being stupid for the same reason that white men are - it subverts, undermines, overturns their power. But even though this Diesel ad is not aimed at women, it sends girls a clear message nevertheless: you can be smart, or you can be hot, but good luck being both.

Dumb and Dumber is one of my favourite movies of all time. (Police officer: "Pull over." Jeff Daniels: "It's a cardigan actually, but thanks for noticing.") I wouldn't want to live in a world without dumb people jokes. From Shakespeare to Charlie Chaplin, fools and clowns have spoken truth to power.

But there's some tired stereotypes out there that could use a rest.

[Addition: Dumb men featured in commercials aren't always white. See, for example, this ad featuring hockey icon Jarome Iginla, or this charmer from Taco Bell.]