The most mind-boggling thing about Canada’s government is the fact that it can’t get anything done. How can it, when its leader is the possessor of international politics’ most Perfect Ass, a firm gobbet of perfect flesh that teases the borders of its woolen confines with every step? As if the gods themselves had shoved a ripe peach, fresh and unyielding, into a pair of slacks and bestowed it with legs, Justin Trudeau’s triumphant butt parades into Parliament day in and day out, and onlookers cannot help but stare. It is proof that miracles exist. But it is also proof that our biology is constantly at work.

Butt science is lopsided. Years of gender-biased research have produced an excess of psychological studies explaining that a healthy female butt is yet another sign of fertility that kicks male reproductive systems into high gear. But when it comes to the ass of a man — and what a man — and its ability to rouse a hormonal storm in people of all genders, the biological mechanism at work is much more difficult to parse. The little research that relates to the attractiveness of the male backside suggests that its shape is a signal to admirers that its proprietor is, indeed, male.

University of California-Los Angeles psychologist Kerri Johnson, Ph.D., is a leading expert in the study of human attraction, and her work has shown that the shape and motion of the human body — butt very much included — is important in figuring out sex and gender and shaping perceived attraction. In her 2007 article in PNAS, she outlined the results of an experiment where participants were asked to rate the movement of animated figures according to attractiveness. Some were hourglass-shaped while others had more tubular torsos; half walked with a sway in the hips while the rest had a swagger in the shoulders. Johnson hypothesized that a person’s body shape and walk somehow shaped how attractive they would seem to onlookers. She was right — attractiveness came down to the body’s consistency with cultural expectations of what men and women should look like.

That's tight.
That's tight.

“When encountering another human, the first judgment an individual makes concerns the other individual’s gender,” Johnson said in a statement, explaining that when a person’s body shape and walking style is inconsistent with what we think befits a man or a woman, attractiveness drops. In another, related study, she found that hourglass-shaped bodies that walked with a shoulder swagger or tubular bodies that walked with swaying hips were seen as incongruous and were often perceived as homosexual. In contrast, “gender-typical” combinations, like a tubular body moving with a shoulder swagger, were perceived as heterosexual. In other words, culture has brainwashed us into thinking that straight guys walk with a swagger in their shoulders but no swing in their hips, and such stereotypes play important roles in how we appraise attractiveness. This particular study didn’t appraise the perceived attractiveness of these bodies, but it did drive home Johnson’s main thesis: That the human eye takes in physical factors like body shape and motion to make judgements about gender, and gender is a key factor in how we think about attractiveness — no matter the sexual preference of the person doing the appraising.

Where does a magnificent butt fit into all of this? It’s very likely that an impeccably thick piece of Canadian ass further highlights the manly way its owner swaggers across the international stage, just as its perfect width and density, when taken in the context of an entire tattooed, yoga-hardened body, might announce the shape of an archetypal Man. Researchers have yet to explore this untouched expanse of scientific backwoods. But if the theory that an attractive man is the sum of his gender-consistent parts (as, of course, defined by culture) is one they wish to pursue further, there’s one utterly flawless specimen, wielding boxing gloves and wearing a pair of obscenely tight trousers, just waiting to be explored.