Prof discusses why we love in Time

If human reproductive behavior is a complicated thing, part of the reason is that it's designed to serve two clashing purposes. On the one hand, we're driven to mate a lot. On the other hand, we want to mate well so that our offspring survive. If you're a female, you get only a few rolls of the reproductive dice in a lifetime. If you're a male, your freedom to conceive is limited only by the availability of willing partners, but the demands of providing for too big a brood are a powerful incentive to limit your pairings to the female who will give you just a few strong young. For that reason, no sooner do we reach sexual maturity than we learn to look for signals of good genes and reproductive fitness in potential partners and, importantly, to display them ourselves. "Every living human is a descendant of a long line of successful maters," says David Buss, an evolutionary psychologist at the University of Texas at Austin. "We've adapted to pick certain types of mates and to fulfill the desires of the opposite sex." One of the most primal of those desires is that a possible partner smells right. Good smells and bad smells are fundamentally no different from each other; both are merely volatile molecules wafting off an object and providing some clue as to the thing that emitted them. Humans, like all animals, quickly learn to assign values to those scents, recognizing that, say, putrefying flesh can carry disease and thus recoiling from its smell and that warm cookies carry the promise of vanilla, sugar and butter and thus being drawn to them. Other humans carry telltale smells of their own, and those can affect us in equally powerful ways.

Why We Love
(Jan. 17)