On the last page, we talked about how age-old signs of fertility can make our brain (and perhaps our sexual organs) take notice of another person. But you might be saying to yourself that love is more than a physical attraction to someone, and it's true that other things are going on when you first encounter a potential mate. For one thing, without sensing it, your brain is sizing up this person against all other past loves. If you're taking notice of a guy with a baseball cap, your brain may nudge you with, "Hey, remember that last man you dated who wore baseball caps? That didn't go so well." Or, your brain may be measuring visual cues against stereotypes about socioeconomic status. If you're spying someone with a briefcase and a business suit, your brain is helping you conclude that this person may work a lot, but at least they can afford a few nice dinners every now and then. Though this insight may disappoint romantics, your brain is only trying to protect you and your assets so that you don't date a broke man who wears baseball caps like your last dud of a boyfriend.
While you're making small talk, you're sizing up his or her voice. A male who speaks deeply and quickly, for example, is likely to be rated as better-looking and highly educated by women around him, according to some studies [source: Fisher]. And of course, if your date is saying things that jibe with your worldview, then you're going to be further besotted. Though we often hear that opposites attract, scientists say it's far more likely that we practice assortative mating, which is partnering off with people who are similar to us. Successful couples may share the same religious values and tax bracket, and they tend to be "in the same league," looks-wise. Yes, what you learned in high school is true -- the pretty people tend to stick with their kind. One study found that people tend to choose people who have the same level of body fat [source: Rowett Research Institute].
Of course, we don't want someone who's too much like us, genetically -- remember our ancestors' mandate to find someone who could make a baby with the best chance of survival? That's why researchers believe that smell is involved when we're sizing up the opposite sex. On the next page, we'll consider why love at first sniff is just as important as love at first sight.