Picture a woman in her early 20s, with smooth and glowing skin, shiny hair, full lips, and bright eyes. She has a perfect 36-24-36 body figure and her voluptuous hips sway gracefully as she walks past by. It’s hard not to imagine such a woman turning heads as she saunters down an alley, gathering awed and admiring looks from the men and possibly a few green-eyed glances from the women.

Why does this type of woman appeal to men? Most of us would probably reason, instinctively, that it’s because she possesses physical attractiveness—this woman is pretty, or beautiful, or gorgeous—you get the drift. It comes as no surprise, then, if a horde of men is lining up to impress and date the woman described above.

But an evolutionary psychologist would make the case that it is not simply this woman’s beauty and sexiness per se that make her especially appealing to the men. Evolutionary psychology is the branch of psychology concerned with explaining human functions and behaviors in terms of how they increase chances of survival and reproduction.

So to the evolutionary psychologist, men are attracted to women of beauty and perfect vital statistics because such characteristics are in fact “cues” — cues that this particular type of woman has a high reproductive capacity as a female. In other words, the woman is highly fertile: smooth skin, shiny hair, full lips and bright eyes indicate youthfulness, and a female of younger age has the potential of producing more children than does a female of older age. The hourglass figure is also more than just a pleasing view of good symmetry and proportion: wide hips indicate the pelvic shape most ideal for childbirth, while ample breasts cue better capacity to nourish offspring once they are born.

Evolutionary psychology asserts that as a human being, the true forces that move you to act the way you do are your need to reproduce, have your genes passed on to the next generation, and ultimately ensure the survival of the species. So if you’re a man, evolutionary psychology explains that you select a particular date or potential mate not because you simply find her “pretty” or “sexy”, but because her prettiness and sexiness are indications that she is likely to give you more children—offering you the best chances of having your genes passed on to the next generation and of granting your particular lineage an increased likelihood of continuing to thrive.

Now, while evolutionary psychology sees men as selecting mates based on who would provide maximum opportunity for bearing offspring, it sees women in an entirely different light. Women are the ones bearing and typically raising the offspring, so what they seek in a potential mate is less about reproductive capacity and more about the mate’s capacity to support and provide for the offspring. In the evolutionary perspective, therefore, women are more attracted to men who can provide the financial resources needed for rearing children [read: rich and preferably holding a high status and power in society].

Now before anyone charges evolutionary psychology of accusing women as mere gold-diggers and men as concerned only with the physical appearance of their mates, note that these speculations were not formed based on what seems instinctively right and observable in common scenarios, but are in fact grounded in research. One of the many studies that support how evolutionary psychology explains the mate selection process in humans is that of Buss and Barnes. Their research asked married couples how much importance they placed on certain characteristics when it came to choosing who they married. The results showed that men were more likely than women to select “good-looking” and “physically attractive” as characteristics they sought in a partner, while women were more likely than men to point out features such as “good earning capacity” and “dependable” as the characteristics they looked for in a potential mate.

However, as consistent as these findings are in many other studies across different cultures, it is important to recognize the limitations of these results, as well as other considerations involved in this theory. It is glaringly obvious that there are also couples consisting of women who’ve hitched with not-so-financially-able-men, and men who’ve paired with women who are not-so-physically-attractive-in-evolutionary-terms.

We are living in a modern society where our needs are no longer as primitive as what our ancestors may have had in ancient times when they were still living in the wild. Therefore, our evolutionary needs and tendencies may be less likely to influence our present behavior and choices, especially in terms of mate selection. For instance, psychology professor Jerry M. Burger has cited that many women nowadays may be more attracted to men who spend more time with them than to dominant, ambitious men who devote all their hours “climbing the corporate ladder.”

So in the modern day, when it comes to romantic relationships—the ones that last the test of time and are truly fulfilling for the people it involves—it’s probably less about instinctual preferences handed down from generation to generation, and more about the mutual love and trust between two people.

What evolutionary psychology explains is possibly more about attraction than about love. Although in many instances, attraction may very well be the spark that first ignites the possibility for a deeper emotion to develop later down the road, the fact stands that mere attraction is not the same as love. And as many people would concur, attraction is definitely not the sole deciding factor in selecting the person to marry and have children with.

Additionally, what evolutionary psychology can explain when it comes to dating behavior and mate selection should not be used as basis to excuse behaviors such as infidelity in a relationship. Please nobody come home to their wife tonight and say, “Sorry, honey, I performed the sex act with this other woman earlier tonight because evolutionary psychology dictates that it is my inherent inclination to try to reproduce as frequently as possible, and I cannot decline such opportunity to fulfill my responsibility to the human species.” (Seriously. Don’t do it, or you’ll die alone.)

When it comes down to it, as humans, the true forces that move us to love the people we love and marry the people we marry are more than just instincts ingrained by the evolutionary process or inspired by any biological need. The nature of deep, moving love—the kind that marks and defines a lifetime—is most probably metaphysical and transcendental, maybe even divine. It cannot be fully explained by evolutionary or other biology-based theories alone, and as many people would agree, ultimately there’s more to relationships, marriage, and life than the need to simply pass on one’s genes or continue a lineage.