The Look of Love: Top 5 Physical Signs of Attraction

Attraction moves in mysterious ways.

When it comes to love (or lust, as the case may be), men and women know what they like when they see it. Ask people to describe their ideal romantic partners, and they might draw a blank or merely offer a vague outline, but that doesn't matter so much, since they'll immediately know when they encounter him or her. According to Rutgers University anthropologist Helen Fisher, the human body is such a finely tuned attraction-seeking machine, it takes only one second to intuitively decide whether someone's physically hot or not [source: Fisher]. Upon closer inspection, we might change our minds, or we just might have found what we've been looking for all along.
To help ensure that the good ones don't get away, our bodies produce a host of physical signs of attraction that grab our attention and direct it toward the dreamboat in question. When those physiological mechanisms kick in, even a brief glimpse of a crush can leave us short of breath and dazed. And unpleasant as some of these reactions might be, we can at least take heart that at some point, the following five lovesick symptoms happen to all of us.
5 Be Still My Beating Heart

Pulses quicken when we're with a crush.

Why do literature and art always associate romance and the heart? Because our hearts are set aflutter, pulses literally racing, at the sight of someone attractive [source: Fisher]. In fact, the heart-attraction relationship is so potent, studies have found that increasing someone's heart rate and then putting him or her near a pretty stranger can artificially ignite a flame of affection [source: Foster et al].
Per usual, the brain is ultimately responsible for this physiological response, not Cupid and his archery acumen. During early-stage romantic love -- scientific terminology for the honeymoon phase -- the brain releases norepinephrine whenever we're around a love interest to shake us into action [source: Obringer]. That adrenaline-like neurotransmitter spurs our motivational decision-making, possibly prodding us to chat up Mr. or Ms. Right. Meanwhile, our adrenaline-addled hearts are likely pumping faster than usual in order to get us through the taxing ordeal [source: Landau].

4 Sweating the Small Stuff

A sweaty handshake might be the start of a romantic partnership.

If you're introduced to someone who immediately makes your heart go gaga, it might be best to avoid a handshake. Sweating palms is a classic physiological response to attraction. The same cocktail of chemicals that prods our pulses also stokes our sweat glands. Collectively known as monoamines, dopamine, norepinephrine and serotonin combine to produce feelings of excitement, with a side of breathlessness and moist hands [source: McLoughlin]. Norepinephrine in particular is the culprit for goading our sweat glands into activation, and since our palms are riddled with up to 3,000 miniscule sweat glands per square inch, they can quickly become a telltale signal of sexual interest.
Men also might be stricken with sweaty palms more often than women. Rutgers University anthropologist Helen Fisher suggests that since men are more visually stimulated than women, their brains dole out bigger doses of monoamines [source: Obringer].

3 Be Mine, Baritone

Let's hope he's belting bass notes.

Repeated studies have confirmed that heterosexual women prefer deeper voices whispering sweet nothings in their ears. In addition to associating lower-pitched male voices with masculinity, women associate those bass notes with authority, larger body size and physical attractiveness [source: O'Luanaigh]. Fortunately for tenors out there, a recent Australian study at least debunked the notion that a deeper voice intimated superior sperm quality [source: Parry].
Perhaps since deeper-pitched voices have attracted such a sexy reputation, people may lower their registers when speaking to their special someones. In a 2010 study, male and female study participants were asked to record messages to be played for fictional recipients. Researchers showed individual participants photos of fictional message recipients; the more attractive participants rated the fictional recipients, the more likely they were to deepen their voices [source: PhysOrg]. But a conflicting study found that the more tantalizing the male face, the higher -- not lower -- women raised their vocal pitch [source: Fraccaro et al]. Either way, it seems we attempt to fine tune our voices to sound like sweet music to our beloveds' ears.

2 Jeepers Peepers

Our pupils dilate when we look at someone we fancy.

Dusty Springfield wasn't talking nonsense when she sang about "The Look of Love." The chart-topping blonde with the golden voice belted out scientifically plausible lyrics about come-hither eyes, as studies have shown that our pupils play an active role in signaling attraction. When we spot a comely face, our brains release dopamine, which triggers pupil dilation [source: Murphy]. Thanks to the surge of dopamine in our brains that excites the nerve endings in our eyes, the pupil muscles contract and dilate our peepers [source: Spiers and Calne].
But pupil preferences aren't uniform across the board, and bigger isn't always better. Whereas heterosexual men find women with larger dilated pupils more feminine and beautiful, most straight women opt for medium male dilations that signal sexual interest, but not to a potentially violent extreme [source: Tombs and Silverman]. However, women who tend to engage in short-term sexual relationships with "bad boys" were googly-eyed for the larger pupils as well [source: Tombs and Silverman].

1 Copycats

Mirroring is a sign of attraction. Matching sweaters optional.

Nineteenth-century British writer and aphorism documentarian Charles Caleb Colton ushered the phrase "Imitation is the sincerest form of flattery" into common usage in 1820 [source: Martin]. Come to find out, Colton's adage applies quite well to interpersonal attraction. When people interact in dating scenarios, and things are going well, body language mirroring often happens subconsciously. For instance, someone will lean in close to the dinner table, and other person follows in suit.
Better yet, without knowing it, these subtle gestures also serve to stoke each other's romantic egos. A 2009 study on mimicry in a speed dating environment revealed that men gave more favorable ratings to women who slightly mirrored their verbal and nonverbal patterns [source: Gueguen]. Scratching their faces after the men scratched their faces, for instance, ultimately increased the women's sexual attractiveness after the 5-minute interaction [source: Jarrett]. If that body language exchange sparks a long-lasting relationship, men's and women's bodies tend to play copycat as they age together as well. According to a 2006 study, the longer couples stick together, well after the jittery symptoms of attraction have calmed, the more they physically begin to look alike [source: Silverman].