(CNN) -- "You had me at 'hello'" -- or did you?
In the new movie, "Her," director Spike Jonze incorporates society's increasing infatuation with smartphones into the plotline of this love-at-first-sound movie -- a futuristic "Sleepless in Seattle" of sorts.
Joaquin Phoenix plays Theodore Twombly, an introverted and subdued writer who ends up falling for "Samantha," his phone's artificially intelligent operating system. ("Her" opens nationwide on January 10.)
Samantha, akin but undoubtedly more advanced than modern-day iOS assistant Siri, is huskily voiced by Scarlett Johansson. (Just don't ask Siri about her.)
There is no physical component to Samantha; she's merely an interactive screen with a warm, responsive voice and custom-made personality picked for the solitary Twombly.
The buzzed-about film is packed with hypotheticals, but the fact that Twombly falls for a voice alone has raised questions about vocal attraction, the power of sound and our desire to truly connect in a hyper-connected yet physically removed world.
While the movie's level of artificial intelligence is still speculative, the scenario certainly isn't too far off base in the realm of digital dating. New York magazine's film critic David Edelstein not only called it one of the best films of the year, he also asked in his review: "Do we even need our bodies? Or is it all in our brains?"
Online dating correspondence via e-mail, private messages and/or chat rooms are a contemporary extension of verbal, non-face-to-face contact. Not to mention the countless hotlines people can call just to have someone to talk to -- whether to discuss personal problems or for sexual pleasure.
Jody Kreiman is a professor at UCLA and co-author of "Foundation of Voice Studies," a textbook that explores voice science, vocal physiology and vocal perception. She says that while humans are vision-dominant, voice plays a "critical role" in our biology.
"Voices are the first stimuli babies recognize," she says. "We're social animals. Interaction is crucial."
However, recognizing a voice also involves activating a slew of associations with that particular tone -- "things like when you heard it, the person's appearance, their tastes and preferences, what you ate when you were together, their siblings' names, all the minutiae that make up knowing someone," she says.
Voice, Kreiman notes, is part of a package.
Unlike the fictional Samantha, no one's personality is crafted to complement another person's -- relationships are messy and complicated by design. (In the film, Twombly's ex-wife says he is in this relationship because he can't handle a real one.)
"Knowing a person only by voice, independent of the kinds of physical details that go into building up a representation of a whole person, seems an impoverished kind of knowing, both of the person and of the voice," she says.
While Kreiman says there's no definitive guide to an attractive voice, listeners generally agree about what is attractive and what isn't.
"On average, most people prefer voices that are moderate in pitch and speaking rate, not nasal, not shrill and with good articulation," she says.
The movie might have a very different outcome if Samantha were voiced by the shrill actress Fran Drescher instead of Johansson, whose breathiness is a vocal turn-on, according to research by David R. Feinberg, founder of the Voice Research Laboratory at McMaster University in Ontario, Canada. (Imagine the iconic "Happy Birthday, Mr. President" sung by Roseanne Barr instead of Marilyn Monroe, and you'll get the picture.)
A recent study out of Albright College in Pennsylvania also indicated both men and women lowered the pitch of their voices when they were attracted to the person they were conversing with.
Diana Sidtis, a professor in the Department of Communicative Sciences and Disorders at New York University, says a high-pitched male voice is rated as less attractive, as is a babyish female voice. Sidtis co-authored "Foundation of Voice Studies" with Kreiman.
She also points out that vocal identity is a "potent stimulus," and voice patterns -- like those of an operating system -- can become familiar very quickly.
"We respond with the entire brain to a personally familiar voice," Sidtis wrote in an e-mail.
Think about your response on the telephone to the mere "hello" of a close friend or family member versus your response to an unfamiliar telemarketer: "In this way, processing a personally familiar voice is essentially different (in neurological and psychological studies) from hearing (or discriminating) an unfamiliar voice," she adds.
Mark Waldman, co-author of "Words Can Change Your Brain," says facial expressions -- like a wry Mona Lisa smile and gentle eye contact -- are undoubtedly key indicators to compassionate communication. Next on the list: a warm tone of voice -- which brings to mind the old saying, "It's not what you say, but how you say it."
Ultimately, though, Waldman says vocal attraction is a fantasy -- just like in the movies. You'll start fantasizing about the whole package; the same way some would with their favorite Hollywood star.
"We meet someone; suspend our suspicions and fantasize what the ideal scenario will be," Waldman says.
At one point in the movie (spoiler alert!), the screen fades to black and the viewer is left to his or her own devices to picture Theodore and Samantha as they consummate their relationship.
Essentially, Twombly is envisioning every other aspect of "her" that doesn't exist -- as is the viewer.