Women may disagree on whether they prefer dark-skinned men with beards, clean-shaven blonds, or men of any appearance sitting in the driver’s seat of a Ferrari—but when asked to rate men they can hear but not see, women miraculously tend to agree: men with deeper voices are rated as more attractive.6 Asked to guess the physical characteristics of the men whose voices they hear in such experiments, women tend to associate low voices with men who are tall, muscular, and hairy-chested—traits commonly considered sexy.
As for men, a group of scientists recently discovered that men unconsciously adjust the pitch of their voices higher or lower in accordance with their assessment of where they stand on the dominance hierarchy with respect to possible competitors. In that experiment, which involved a couple hundred men in their twenties, each man was told he’d be competing with another man for a lunch date with an attractive woman in a nearby room.7 The competitor, it was explained, was a man in a third room.
Each contestant communicated with the woman via a digital video feed, but when he communicated with the other man, he could only hear him, and not see him. In reality, both the competitor and the woman were confederates of the researchers, and they followed a fixed script. Each man was asked to discuss—with both the woman and his competitor—the reasons he might be respected or admired by other men. Then, after pouring his heart out about his prowess on the basketball court, his potential for winning the Nobel Prize, or his recipe for asparagus quiche, the session was ended, and he was asked to answer some questions assessing himself, his competitor, and the woman. The subjects were then dismissed. There would, alas, be no winners anointed.
The researchers analyzed a tape recording of the male contestants’ voices and scrutinized each man’s answers to the questionnaire. One issue the questionnaires probed was the contestant’s appraisal of his level of physical dominance as compared to that of his competitor. And the researchers found that when the participants believed they were physically dominant—that is, more powerful and aggressive—they lowered the pitch of their voices, and when they believed they were less dominant, they raised the pitch, all apparently without realizing what they were doing.
From the point of view of evolution, what’s interesting about all this is that a woman’s attraction to men with low voices is most pronounced when she is in the fertile phase of her ovulatory cycle.8 What’s more, not only do women’s voice preferences vary with the phases of their reproductive cycle, so do their own voices—in their pitch and smoothness—and research indicates that the greater a woman’s risk of conception, the sexier men find her voice.9 As a result, both women and men are especially attracted to each other’s voices during a woman’s fertile period. The obvious conclusion is that our voices act as subliminal advertisements for our sexuality. During a woman’s fertile phase, those ads flash brightly on both sides, tempting us to click the “Buy” button when we are most likely to obtain not only a mate but, for no extra (upfront) cost, also a child.
But there is still something to be explained. Why is it a deep voice, in particular, that attracts women? Why not a high, squeaky voice or one in mid-range? Was it just nature’s random choice, or does a deep voice correlate with male virility? We’ve seen that—in a woman’s eyes—a deep voice is considered indicative of men who are taller, hairier, and more muscular. The truth is, there is little or no correlation between a deep voice and any of those traits.10 However, studies show that what does correlate with a low-pitched voice is testosterone level. Men with lower voices tend to have higher levels of that male hormone.11
It is difficult to test whether nature’s plan works—whether men with more testosterone really produce more children—because modern birth control methods prevent us from judging a man’s reproductive potential by the number of children he fathers. Still, a Harvard anthropologist and some colleagues found a way. In 2007 they traveled to Africa to study the voices and family size of the Hadza people, a monogamous hunter-gatherer population of about one thousand in the savannah woodlands of Tanzania, where men are still men, tubers are plentiful, and no one uses birth control. In those savannahs, the baritones indeed beat the tenors. The researchers found that while the pitch of women’s voices was not a predictor of their reproductive success, men with lower-pitched voices on average fathered more children.12 A woman’s sexual attraction to a deep male voice does seem to have a neat evolutionary explanation. So if you’re a woman and you want a large family, follow your instincts and go for the Morgan Freeman type.
YOU’RE CERTAINLY MORE likely to satisfy an employee by saying, “I value you and will do everything I can to increase your salary” than by explaining, “I have to keep my budget down, and one of the easiest ways is to pay you as little as possible.” But you can also communicate either sentiment, though not the precise meaning, simply by the way you say it. That’s why some people can recount things like “He enjoyed chewing on plump grapes while speeding down a mountain in a monogrammed bobsled” and still give the impression of being profound, while others can say, “The large-scale geometry of the universe is determined by the density of the matter within it” and sound like they are whining. The pitch, timbre, volume, and cadence of your voice, the speed with which you speak, and even the way you modulate pitch and volume, are all hugely influential factors in how convincing you are, and how people judge your state of mind and your character.
Scientists have developed fascinating computer tools that allow them to determine the influence of voice alone, devoid of content. In one method they electronically scramble just enough syllables that the words cannot be deciphered. In another, they excise just the highest frequencies, which wreaks havoc with our ability to accurately identify consonants. Either way, the meaning is unintelligible while the feel of speech remains. Studies show that when people listen to such “content-free” speech, they still perceive the same impressions of the speaker and the same emotional content as do subjects who hear the unaltered speech.13 Why? Because as we are decoding the meaning of the utterances we call language, our minds are, in parallel, analyzing, judging, and being affected by qualities of voice that have nothing to do with words.
In one experiment scientists created recordings of a couple dozen speakers answering the same two questions, one political, one personaclass="underline" “What is your opinion of college admissions designed to favor minority groups?” and “What would you do if you suddenly won or inherited a great sum of money?”14 Then they created four additional versions of each answer by electronically raising and lowering the speakers’ pitch by 20 percent, and by quickening and slowing their speech rate by 30 percent. The resulting speech still sounded natural, and its acoustic properties remained within the normal range. But would the alterations affect listeners’ perceptions?
The researchers recruited dozens of volunteers to judge the speech samples. The judges each heard and rated just one version of each speaker’s voice, randomly chosen from among the original and the altered recordings. Since the content of the speakers’ answers didn’t vary among the different versions but the vocal qualities did, differences in the listeners’ assessments would be due to the influence of those vocal qualities and not the content of the speech. The result: speakers with higher-pitched voices were judged to be less truthful, less emphatic, less potent, and more nervous than speakers with lower-pitched voices. Also, slower-talking speakers were judged to be less truthful, less persuasive, and more passive than people who spoke more quickly. “Fast-talking” may be a cliché description of a sleazy salesman, but chances are, a little speedup will make you sound smarter and more convincing. And if two speakers utter exactly the same words but one speaks a little faster and louder and with fewer pauses and greater variation in volume, that speaker will be judged to be more energetic, knowledgeable, and intelligent. Expressive speech, with modulation in pitch and volume and with a minimum of noticeable pauses, boosts credibility and enhances the impression of intelligence. Other studies show that, just as people signal the basic emotions through facial expressions, we also do it through voice. For example listeners instinctively detect that when we lower the usual pitch of our voice, we are sad and that when we raise it, we are angry or fearful.15